1 Introduction

Fritillaria thunbergii Miq., a perennial herb of the genus Fritillaria in the family Liliaceae, is used medicinally as its dried bulb. It is one of the commonly used traditional Chinese medicinal materials in China and a representative geo-authentic medicinal material of Zhejiang Province. F. thunbergii has a long history of medicinal use and is clinically applied mainly for clearing heat and resolving phlegm, relieving cough and promoting expectoration, dissipating nodules, and resolving carbuncles. It has shown important application value in the intervention of respiratory diseases, pneumonia, inflammatory diseases, and related metabolic disorders (Nile et al., 2021). Modern pharmacological and phytochemical studies have shown that the bulbs of F. thunbergii contain various active substances, including alkaloids, polysaccharides, saponins, flavonoids, and volatile components. Among them, steroidal alkaloids such as peimine and peiminine have received particular attention and constitute an important material basis for its antitussive, expectorant, anti-inflammatory, antitumor, and antioxidant pharmacological effects (Huang et al., 2024a; Zou et al., 2026). Because peimine-type components are often regarded as important quality markers of F. thunbergii medicinal materials and their preparations, their content directly affects clinical efficacy, quality evaluation, and commercial value (Sui et al., 2021; Cheng et al., 2023; Zhou et al., 2023). With the continuous advancement of traditional Chinese medicine modernization and quality standardization of Chinese medicinal materials, F. thunbergii not only maintains stable demand in the field of traditional decoction pieces, but is also increasingly applied in Chinese patent medicine development, functional product research, and the comprehensive utilization of medicinal plant resources. Its industrial value and market attention have therefore continued to increase.

From the perspective of industrial development, F. thunbergii has medicinal, economic, and regional specialty agricultural value, making it an important crop for promoting local Chinese medicinal material industries and increasing farmers’ income. With growing market demand and ecological constraints on wild resources, the supply of F. thunbergii has gradually shifted from wild collection to artificial cultivation. Stable, high-yield, and high-quality cultivation has therefore become a key issue in current industrial development (Sui et al., 2021; Du et al., 2024; Liu et al., 2025a). Major production areas such as Zhejiang have developed a relatively mature cultivation foundation as well as processing and distribution systems. However, in production practice, F. thunbergii still faces problems such as yield fluctuation, uneven quality, and unstable contents of active components. Since the underground bulb is the medicinal part of F. thunbergii, yield formation is influenced not only by cultivar, seed bulb quality, and cultivation management, but also closely related to light, temperature, water, soil, and regional ecological conditions. Existing studies have shown that cultivation environments and agronomic measures, including fertilizer type and application rate, potassium nutrition, organic fertilizer and biochar amendment, shading intensity, soil disinfestation, and biological control, can significantly affect bulb biomass, peimine/peiminine contents, and levels of other steroidal alkaloids in F. thunbergii (Cheng et al., 2023; Huang et al., 2024a). Therefore, different cultivation environments may affect final yield and medicinal quality by changing plant growth rhythm, photosynthetic efficiency, dry matter accumulation, rhizosphere microecology, and bulb enlargement.

At present, F. thunbergii production has gradually shifted from traditional experience-based cultivation to standardized, large-scale, and high-quality cultivation. Simply pursuing bulb yield can no longer meet the requirements of the medicinal material market and quality evaluation systems. Studies have shown that yield-oriented intensive cultivation may be associated with a decline in the levels of medicinal components in bulbs, while the accumulation of peimine-type steroidal alkaloids varies with species, organs, developmental stages, and environmental conditions (Sui et al., 2021; Huang et al., 2024a). For example, appropriate potassium and organic fertilizer application can simultaneously increase bulb yield and peimine content, whereas shading or certain stress-mimicking measures may increase alkaloid concentrations but are often accompanied by reduced biomass (Liu et al., 2025a). This indicates that high yield does not necessarily equate to high quality. If cultivation environment regulation is inappropriate, plant growth may be restricted, disease incidence may increase, bulb marketability may decline, or peimine accumulation may be insufficient. Therefore, in F. thunbergii production, greater attention should be paid to the coordination between “yield formation” and “quality formation.” On the one hand, optimizing light-temperature-water-fertilizer management, improving soil structure, regulating the field microclimate, and reducing continuous cropping obstacles can enhance plant growth stability and bulb yield. On the other hand, the promoting effects of suitable environmental conditions on peimine synthesis, transport, and accumulation should also be emphasized to provide a basis for improving the medicinal quality of F. thunbergii.

This study will explore the effects of cultivation environment on the yield of Fritillaria thunbergii and peimine accumulation. Focusing on the growth and developmental characteristics, yield formation process, and peimine accumulation patterns of F. thunbergii, this study will systematically analyze the regulatory effects of light, temperature, water, soil, regional ecological conditions, and cultivation patterns on its growth and quality formation. Existing studies have explored individual factors such as potassium application rate, organic fertilizer type, shading treatment, soil disinfestation, and biological control; however, comprehensive evaluations that simultaneously link specific cultivation environments with bulb yield and peimine accumulation remain relatively limited. In addition, transcriptomic and metabolomic studies have shown that the effects of cultivation environment on the growth and quality of F. thunbergii may be mediated by regulating hormone signaling, rhizosphere microecology, and the expression of key genes involved in steroidal alkaloid biosynthesis. Therefore, this study will further analyze the possible mechanisms by which environmental factors regulate photosynthesis, dry matter accumulation, and secondary metabolism. It aims to clarify the intrinsic relationships between cultivation environment, yield formation, and peimine accumulation in F. thunbergii, providing theoretical references for ecological suitability zoning, standardized cultivation, optimization of high-quality and high-yield cultivation techniques, and construction of a coordinated yield-quality evaluation system. It also offers practical insights for the green, standardized, and sustainable development of the F. thunbergii industry.

2 Growth and Development Characteristics of Fritillaria thunbergii and Features of Peimine Accumulation

2.1 Biological characteristics and growth cycle of Fritillaria thunbergii

Fritillaria thunbergii Miq. is a perennial geophyte of the genus Fritillaria in the family Liliaceae. Its underground bulb is used medicinally, serving not only as a storage organ for nutrients but also as the main site for the accumulation of steroidal alkaloids such as peimine and peiminine (Nile et al., 2021; Huang et al., 2024a). The plant usually develops aboveground stems and leaves from sprouting bulbs. The leaves perform photosynthesis, and the photosynthetic products are gradually allocated to the underground bulbs through assimilate transport, thereby supporting bulb enlargement and the accumulation of medicinal constituents. F. thunbergii is suitable for growth in mild, humid, cool, well-ventilated environments with loose soil and good drainage. It is relatively sensitive to high temperature, waterlogging, and soil compaction. At present, commercial production mainly relies on artificial cultivation systems, and some cultivation patterns regulate light and microclimate through field shading facilities to simulate its native shaded mountain habitats, thereby improving the plant growth environment and the conditions for bulb quality formation (Liu et al., 2025a).

In terms of growth cycle, F. thunbergii generally undergoes several stages, including bulb dormancy, dormancy release, sprouting and emergence, leaf expansion and vegetative growth, bulb enlargement, and aboveground withering. During dormancy, the bulb mainly undergoes physiological regulation and nutrient storage, laying the foundation for sprouting in the following growing season. Studies have shown that storing F. thunbergii bulbs at low temperatures of 4°C~10°C for several weeks can reduce the content of phenolic compounds and alter the activities of phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO), changes that are closely associated with dormancy release. In vitro and ex situ studies on Fritillaria bulbs have also shown that appropriate temperature regimes and gibberellin (GA) signaling contribute to fresh weight increase and sprouting, whereas unsuitable conditions may delay growth and prolong dormancy (Marković et al., 2020; Marković et al., 2021). In addition, micropropagation systems established using bulb scale sections can regenerate numerous bulblets within a short period, but these bulblets still require cold treatment to achieve synchronized sprouting. This indicates that the rhythm of “dormancy-cold induction-sprouting growth” is an important developmental pattern in F. thunbergii and related Fritillaria species.

Bulb development in F. thunbergii is also jointly regulated by plant hormones and genetic factors. Transcriptomic studies have found that the GGPS1 family gene FtGGPS can influence bulb development and differences in bulb size among cultivars by regulating the levels of gibberellin (GA) and abscisic acid (ABA) (Xu et al., 2026). Meanwhile, ABA-related signaling is also considered to be associated with increased bulb yield under certain fertilization regimes, indicating that the growth cycle of F. thunbergii is regulated not only by external environmental factors such as temperature, light, and water, but also by finely tuned endogenous hormone signaling (Huang et al., 2024a). Therefore, when understanding the growth and developmental patterns of F. thunbergii, it should be regarded as the result of the combined effects of environmental factors, hormonal regulation, photosynthate accumulation, and bulb storage function.

2.2 Major Factors influencing yield formation in Fritillaria thunbergii

The yield of F. thunbergii mainly depends on the number of effective plants per unit area, single-bulb weight, degree of bulb enlargement, and marketable traits. Among these factors, seed bulb quality is the fundamental condition for yield formation. Plump, healthy, disease-free seed bulbs usually have stronger sprouting capacity and growth vigor, which can improve emergence rate and population uniformity. In contrast, small, diseased, or improperly stored seed bulbs may easily cause uneven emergence, weakened growth, and disease transmission, ultimately affecting bulb enlargement and yield stability. Since the underground bulb is both the medicinal and commercial part of F. thunbergii, yield formation is essentially the result of a continuous process involving aboveground photosynthetic establishment, assimilate accumulation, and underground bulb enlargement. Therefore, production should emphasize germplasm selection, seed bulb grading, pre-sowing treatment, and population establishment quality to lay a foundation for high yield in later stages.

Cultivation environment is the core external factor affecting yield formation in F. thunbergii. Nutrient management, light conditions, and rhizosphere microecology are currently key research directions. Field experiments have shown that different types of basal fertilizers have significant effects on the yield and quality of F. thunbergii. Among them, organic fertilizer treatment can produce higher bulb yield and higher peimine and peiminine contents than raw chicken manure or plant ash, indicating that organic fertilizer has a better coordinating effect between biomass accumulation and alkaloid formation (Huang et al., 2024a). Potassium nutrition is also an important factor affecting dry matter formation. Within an appropriate application range, potassium fertilizer significantly increases bulb biomass and yield by approximately 4%~11% compared with the unfertilized control, suggesting that potassium contributes to assimilate transport, bulb filling, and yield formation (Liu et al., 2025a). Therefore, rational fertilization, especially the combination of organic fertilizer input and appropriate potassium application, is an important technical pathway for improving the yield and quality of F. thunbergii.

Light intensity and its associated microclimate exert dual effects on yield formation in F. thunbergii. Suitable light is beneficial for leaf photosynthesis and dry matter accumulation, whereas insufficient light limits carbon assimilation and reduces bulb biomass. However, moderate shading may also improve field temperature and humidity conditions and alleviate strong light and high-temperature stress. Studies have shown that strong shading can significantly increase the concentration of bioactive components in bulbs, but it reduces biomass and overall yield, and severe yield reduction may occur under extremely low light transmittance. Moderate shading combined with appropriate potassium supply can partially compensate for shading-induced yield reduction while maintaining or increasing active component content (Liu et al., 2025a). In addition, rhizosphere microbial communities are also involved in regulating the balance between yield and quality. Shading and potassium can jointly alter soil pH and available nutrient status, enriching bacterial and fungal groups positively correlated with bulb growth and medicinal constituent accumulation, such as Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Burkholderia-Caballeronia-Paraburkholderia, Chryseobacterium, Brevundimonas, and Phoma. This indicates that yield formation in F. thunbergii is not determined by a single factor, but by the coordinated effects of light, nutrients, rhizosphere microecology, and field management.

2.3 Types, accumulation characteristics, and quality evaluation significance of peimine

Peimine is an important steroidal alkaloid active component in F. thunbergii and serves as an important material basis for evaluating its medicinal quality. Among these components, peimine is a cevanine-type steroidal alkaloid and often coexists in F. thunbergii bulbs with peiminine, peimisine, imperialine, and other steroidal alkaloids (Nile et al., 2021; Shan et al., 2022). Metabolomic studies have shown that peimine, peiminine, and related cevanine-type alkaloids are relatively abundant alkaloid components in Fritillaria species, especially in bulb tissues, where their contents are usually higher than those in aboveground parts (Liao et al., 2023). In aqueous and hydroethanolic extracts of F. thunbergii bulbs, peimine, peiminine, peimisine, and their glycosides have been identified as major components using UPLC-QTOF-MS and other techniques, with characteristic fragmentation patterns further confirming the structures of these compounds (Huang et al., 2024a; Jeong et al., 2024; Zou et al., 2026). Therefore, peimine-type components are not only important constituents of the pharmacodynamic basis of F. thunbergii, but also provide detectable and quantifiable chemical indicators for modern quality evaluation.

Peimine accumulation shows obvious organ specificity and stage specificity. Since the bulb is the medicinal part of F. thunbergii, it is both the core site of yield formation and an important site of peimine accumulation. In the early growth stage, vegetative growth and leaf establishment predominate, and photosynthetic products are mainly used for the development of aboveground parts and roots. As growth progresses, assimilates are gradually transported to the underground bulbs, bulb enlargement and secondary metabolic activity are enhanced, and the accumulation of peimine and related steroidal alkaloids changes accordingly. Comparative metabolomic and time-series metabolomic studies on related Fritillaria species have shown that peimine and peiminine mainly accumulate in bulbs and often reach relatively high levels at later developmental stages or shortly after aboveground withering, indicating that alkaloid enrichment is closely associated with bulb maturation (Figure 1) (Duan et al., 2022; Duan et al., 2023). From the perspective of biosynthesis, peimine may originate from cholesterol metabolism and involve the terpenoid backbone pathway and downstream steroid pathways. Cytochrome P450 enzymes and glycosyltransferases may participate in its structural diversification, but the complete enzymatic biosynthetic route remains to be further clarified (Nile et al., 2021; Shan et al., 2022; Liao et al., 2023).

The accumulation of peimine and related steroidal alkaloids is sensitive to cultivation practices and environmental conditions. Studies have shown that, compared with less optimized treatments, organic fertilizer application and appropriate potassium supply under shading conditions can significantly increase peimine and peiminine levels in bulbs (Huang et al., 2024a; Liu et al., 2025a). The application of biocontrol agents during cultivation can not only improve plant growth, but also increase the contents of peimine, peiminine, and other steroidal alkaloids. This effect may be related to the regulation of key enzyme activities, oxidative phosphorylation, amino acid metabolism, cytochrome P450 enzymes, and transcription factors such as MYB and bHLH (Cheng et al., 2023). From the perspective of quality evaluation, the quality of F. thunbergii should not be judged solely by yield, but should be comprehensively evaluated based on bulb size, morphology, dry matter content, peimine and peiminine contents, safety, and pharmacological indicators. Given the central role of peimine, peiminine, and related steroidal alkaloids in antitussive, anti-inflammatory, and other pharmacological effects, they are widely regarded as core quality markers of F. thunbergii. They constitute an important basis for modern chromatographic quality evaluation systems and provide a foundation for linking cultivation environment with clinical efficacy (Nile et al., 2021; Zhou et al., 2023; Zou et al., 2026).

3 Effects of Light and Temperature Conditions on the Yield of Fritillaria thunbergii and Peimine Accumulation

3.1 Effects of light intensity and shading conditions on plant growth

Light is an important environmental factor affecting aboveground growth, photosynthesis, and dry matter accumulation in Fritillaria thunbergii. During growth, F. thunbergii relies on its leaves for photosynthesis, converting light energy into organic matter, which is subsequently transported to the underground bulbs for bulb enlargement and the accumulation of medicinal constituents. Appropriate light intensity helps improve leaf photosynthetic efficiency, promotes robust plant growth, and prolongs the functional duration of leaves, thereby providing sufficient material basis for subsequent bulb formation. Existing studies have shown that light intensity directly constrains photosynthesis and dry matter accumulation in F. thunbergii, and excessive shading significantly inhibits carbon assimilation and plant growth. Under strong shading conditions, namely approximately 5% light transmittance, bulb biomass and yield of F. thunbergii decline significantly; compared with full light, shading treatment can reduce bulb biomass and yield by approximately 17% and 9%, respectively (Liu et al., 2025a). Single-factor shading experiments have also shown that although shading can increase the content of active ingredients, shading alone can reduce bulb biomass by approximately 11%. This indicates that F. thunbergii still requires a certain light basis to achieve high yield, and yield loss increases when light intensity falls below its photosynthetic requirement.

However, F. thunbergii is not suitable for long-term growth under conditions of both strong light and high temperature. Excessively strong light can accelerate leaf water loss, damage the photosynthetic system, and promote premature senescence. Especially in late spring, when temperatures rise, strong light may aggravate heat stress, causing early withering of the aboveground parts and shortening the effective growth period. Since yield formation in F. thunbergii depends on the continuous transport of assimilates from the aboveground parts to the bulbs, premature leaf senescence directly affects underground bulb enlargement and dry matter accumulation. Therefore, in cultivation practice, light conditions should be reasonably regulated according to the climatic characteristics of the production area and the growth stage, so as to avoid growth imbalance caused by excessively weak or excessively strong light. Under low-light conditions, F. thunbergii exhibits certain morphological and physiological plasticity, such as enhancing light capture by adjusting leaf traits and chlorophyll content. This is similar to the phenomenon observed in crops such as strawberry, where low light reduces photosynthetic rate and growth but increases pigment content and alters leaf area (Liu et al., 2025a).

Moderate shading is an important measure for improving the field microclimate of F. thunbergii. Shading cultivation can reduce light intensity and surface temperature, alleviate damage caused by direct strong light to leaves, help maintain soil moisture, and improve the plant growth environment. Understory cultivation and sunshade-net cultivation can, to some extent, simulate the cool and humid ecological requirements of F. thunbergii, helping delay premature senescence of the aboveground parts and maintain relatively stable photosynthetic function. However, the degree of shading must be properly controlled, as excessive shading reduces photosynthetic accumulation and is unfavorable for bulb enlargement. Studies have shown that sufficient potassium supply can partially alleviate the adverse effects of shading on the growth of F. thunbergii and increase bulb biomass and yield under shading conditions, although these indicators still cannot fully recover to the level of the unshaded control (Liu et al., 2025a). Therefore, combining moderate shading with optimized nutrient supply is an important pathway for balancing light energy utilization, stress mitigation, and yield stability.

3.2 Effects of temperature changes on sprouting, leaf expansion, and bulb enlargement

Temperature is one of the core factors regulating the growth rhythm and phenological process of F. thunbergii. F. thunbergii has a biological preference for cool conditions, and its sprouting, emergence, leaf expansion, and bulb enlargement are closely related to temperature changes. Under suitable low-temperature and mild climatic conditions, seed bulbs can successfully break dormancy and sprout, aboveground growth is relatively uniform, and leaves expand fully, which is conducive to the formation of a good population structure. Studies have shown that temperature plays a key role in breaking bulb dormancy and initiating sprouting in F. thunbergii. Storage of F. thunbergii bulbs at 10°C for 30~45 days or at 4°C for 45~60 days is considered a critical period for dormancy release. During this process, the content of phenolic compounds decreases and related enzyme activities change, indicating that sprouting induction involves a temperature-dependent biochemical mechanism. Low-temperature pretreatment of in vitro-produced bulblets at approximately 5°C for several weeks can also promote uniform sprouting after transplantation, indicating that exposure to low temperature is important for successful emergence and population establishment (Marković et al., 2021).

Once dormancy is released, subsequent temperature conditions regulate leaf expansion and bulb enlargement by affecting carbon acquisition and assimilate allocation. Leaf expansion and vegetative growth stages are relatively sensitive to temperature. Suitable temperatures promote leaf expansion, root absorption, and photosynthesis, enabling plants to establish a strong vegetative growth foundation. When temperatures are too high, transpiration increases, water consumption accelerates, and leaves are prone to wilting, yellowing, or premature senescence, leading to decreased photosynthetic capacity. Meanwhile, high temperature may also alter the balance of carbon and nitrogen metabolism in plants, resulting in insufficient transport of assimilates to underground bulbs and ultimately affecting bulb enlargement and marketable yield. Studies on related Fritillaria species have shown that in geophytes such as Fritillaria meleagris, compared with 7°C, higher temperatures during post-dormancy growth, approximately 24°C, combined with gibberellin treatment can significantly increase bulb fresh weight and sprouting rate, whereas low-temperature conditions slow biomass accumulation (Figure 2) (Marković et al., 2020). Therefore, F. thunbergii does not require low temperatures throughout its entire growth cycle; rather, it requires appropriate low temperature to complete dormancy release, followed by moderately warm conditions to promote leaf expansion, photosynthesis, and bulb enlargement.

The bulb enlargement stage is the key period for yield formation in F. thunbergii, during which temperature conditions directly affect dry matter accumulation and underground organ development. A mild, stable environment with an appropriate diurnal temperature difference is conducive to the accumulation of organic matter through photosynthesis during the day and to reduced respiratory consumption at night, thereby promoting the transfer of more assimilates to the bulbs. If persistent high temperatures occur during this stage, the aboveground parts are prone to premature withering, the duration of bulb enlargement is shortened, and single-bulb weight decreases. In vitro culture studies have shown that under a 16 h light/8 h dark regime, approximately 25°C is the most favorable temperature for bulblet regeneration and early growth of F. thunbergii. Compared with continuous darkness at the same temperature, this condition better supports rapid leaf development and bulblet enlargement. Thus, temperature not only affects the progression of each growth stage of F. thunbergii, but also determines whether the plant can complete sufficient material accumulation within a limited growing period. Overall, the growth of F. thunbergii requires a “cool-warm” temperature sequence: sufficient low temperature to break dormancy, followed by moderately warm conditions to promote leaf establishment, photosynthesis, and bulb weight gain.

3.3 Regulatory effects of light-temperature interaction on peimine accumulation

As an important secondary metabolite in F. thunbergii, peimine synthesis and accumulation are influenced not only by genetic factors but also by external environmental conditions such as light and temperature. Light provides the material basis for the synthesis of peimine and other secondary metabolites by affecting photosynthesis and carbon source supply, whereas temperature influences the formation and accumulation of active ingredients by regulating enzyme activity, respiratory metabolism, and growth processes. Existing studies have shown that light conditions not only regulate the growth of F. thunbergii, but also strongly affect the accumulation of steroidal alkaloids, including peimine. In field and shade-house experiments, shading generally increased the total active ingredient content in F. thunbergii bulbs by approximately 11%~21%, even though it reduced biomass (Liu et al., 2025a). Under the combined effects of shading and optimized potassium supply, the contents of peimine and related steroidal alkaloids, including imperialine, peiminine, and cyclopamine, were significantly higher than those under full light. Despite a certain yield penalty, the total alkaloid accumulation per unit area was still increased.

The effects of light and temperature on peimine accumulation are usually not independent, but rather show coordinated regulation. Appropriate light is conducive to dry matter accumulation, while suitable low temperature or a relatively large diurnal temperature difference may reduce respiratory consumption and promote the accumulation of active ingredients in bulbs. Within a certain range, mild environmental stress may also activate plant defense responses and secondary metabolic pathways, thereby promoting the synthesis of alkaloid components. Transcriptomic and metabolomic analyses have shown that shading under sufficient potassium supply can upregulate key genes and pathways involved in steroidal alkaloid biosynthesis, including farnesyl pyrophosphate synthase and multiple transcription factors, thereby linking changes in light microclimate with the molecular regulation of peimine synthesis (Liu et al., 2025a). These findings indicate that low to moderate light is not only an ecological environmental factor, but may also act as a quality-regulating “signal,” promoting the diversion of carbon flow from growth expansion toward secondary metabolism and thereby increasing peimine concentration.

Temperature integrates with light signals to jointly regulate developmental processes and metabolic allocation in F. thunbergii. Low-temperature treatment can regulate bulb dormancy and phenolic metabolism, indirectly affecting the length of the growth period available for alkaloid accumulation; subsequent moderately warm conditions help enhance photosynthetic capacity and biomass formation (Marković et al., 2020). Controlled-environment studies have shown that higher temperature can synergize with lower light intensity and extended photoperiod to promote leaf expansion and total photon capture, thereby increasing biomass without reducing secondary metabolite levels under suitable spectral conditions (Jeong et al., 2025). In Fritillaria systems, in vitro studies have shown that a defined temperature of approximately 25°C combined with controlled light quality can significantly increase the contents of peimine and related isosteroidal alkaloids in callus or seedlings (Chen et al., 2020; Peng et al., 2024). Therefore, in the cultivation of F. thunbergii, light and temperature management should take into account both yield formation and peimine accumulation. Through moderate shading, sufficient low-temperature treatment, suitable growing-season temperature, field ventilation, and microclimate regulation, high peimine content can be promoted while maintaining acceptable bulb yield.

4 Effects of Water Conditions on the Yield of Fritillaria thunbergii and Peimine Accumulation

4.1 Effects of soil moisture on root growth and bulb development

Water is an important ecological factor affecting the growth, development, and yield formation of Fritillaria thunbergii. F. thunbergii prefers moist conditions but is intolerant of waterlogging. Since both its roots and bulbs grow in the soil, they are sensitive to changes in soil water content and its spatial distribution. Appropriate soil moisture can maintain normal root extension and absorption functions, promote the uptake and transport of mineral nutrients, and provide necessary conditions for aboveground growth and underground bulb enlargement. Rhizobox and soil column studies have shown that root growth is mainly driven by the vertical distribution of soil moisture. Roots tend to proliferate in moist soil layers, whereas root elongation is inhibited when soil moisture falls below a critical threshold. After local soil rewetting, roots can dynamically adjust growth allocation within 48 h, showing a clear “hydromatching” phenomenon (Maan et al., 2023; Ceolin et al., 2025). This suggests that maintaining a suitable and relatively uniform moisture environment within the main rooting depth of F. thunbergii is conducive to continuous root exploration of the soil space, stable water and nutrient supply, and sustained bulb enlargement.

In the early growth stage of F. thunbergii, suitable soil moisture helps promote seed bulb sprouting, uniform emergence, and root establishment. Well-developed roots enhance plant utilization of water and nutrients and improve population growth uniformity. After entering the vegetative growth and bulb enlargement stages, the plant’s demand for water supply further increases. At this stage, if soil moisture is sufficient and aeration is good, leaves can maintain high photosynthetic efficiency, allowing assimilates to be continuously transported to underground bulbs and promoting bulb filling and dry matter accumulation. Studies have shown that as roots develop, they can alter soil structure and form subzones with high, medium, and low moisture levels. After irrigation, moisture changes rapidly in the near-root zone, whereas soil moisture farther from the roots remains relatively stable (Zhang et al., 2021). This indicates that water management in F. thunbergii should focus not only on overall field soil water content, but also on the spatiotemporal changes in moisture within the rhizosphere microenvironment.

It should be noted that the water requirement of F. thunbergii does not mean that more water is always better; instead, it emphasizes the coordination between moisture and aeration. Soil moisture stability is as important as absolute water content. Studies on tomato seedlings have shown that, compared with fluctuating moisture conditions, maintaining stable soil moisture through precise water replenishment can improve shoot and root morphology, photosynthesis, and water-use efficiency, even when the average water content is similar (Li et al., 2023). For F. thunbergii, which depends on a healthy fibrous root system to provide carbohydrates and precursors for steroidal alkaloid biosynthesis, avoiding large fluctuations between dry and wet soil conditions may be important for uniform bulb development and stable peimine accumulation. If soil moisture is excessive, soil pores become filled with water, restricting root respiration and reducing root vitality. Meanwhile, because the bulb tissue of F. thunbergii is relatively tender, it is more susceptible to pathogenic microbial infection under poor aeration and excessive humidity. Therefore, water management should follow the basic principles of maintaining moderate moisture, avoiding long-term waterlogging, and preserving rhizosphere aeration, so as to maintain a balance among root growth, bulb development, and soil aeration.

4.2 Effects of drought, waterlogging, and wet injury on yield formation

Drought stress directly restricts the normal growth of F. thunbergii. When soil moisture is insufficient, plants first exhibit difficulty in root water uptake, leaf water loss, stomatal closure, and reduced photosynthetic efficiency. As drought persists, leaves may wilt, yellow, or senesce prematurely, shortening the functional period of the aboveground parts and resulting in insufficient accumulation of photosynthetic products. Since the yield of F. thunbergii mainly derives from the enlargement and filling of underground bulbs, inhibited aboveground growth reduces the assimilates transported to the bulbs, ultimately causing a decline in single-bulb weight, marketability, and total yield. Studies on medicinal plants have also shown that drought stress usually suppresses biomass and yield. A meta-analysis covering 27 medicinal plant species found that moderate and severe drought stress significantly reduced plant relative water content and yield while strongly activating enzymatic antioxidant systems (Tan and Gören, 2024). In field experiments on Balangu (Lallemantia spp.), moderate and severe drought reduced seed yield and oil content, although phenolic compounds and antioxidant enzyme levels increased (Omidi et al., 2018). These results suggest that although drought may induce certain defensive metabolic responses, long-term water deficiency is generally unfavorable for bulb yield formation in F. thunbergii.

Compared with drought, waterlogging and wet injury are equally serious hazards in F. thunbergii production, and may be even more severe in some rainy or poorly drained regions. Long-term soil waterlogging causes rhizosphere hypoxia, inhibits root respiration, reduces nutrient absorption capacity, and induces root rot and bulb rot. Reviews on waterlogging stress indicate that soil oxygen depletion after saturation leads to enhanced anaerobic respiration, reduced dry matter accumulation, impaired nutrient uptake, especially potassium and calcium uptake, and significant yield losses in many crops (Manghwar et al., 2024). Species-specific experiments have shown that complete waterlogging significantly reduces fine-root growth and transpiration, whereas partial waterlogging may promote root proliferation in non-flooded upper soil layers to compensate for damaged deep roots (Fujita et al., 2021). For underground bulb crops such as F. thunbergii, prolonged saturation around the bulbs and main root zone can easily cause root decay, wet injury symptoms, and reduced population stability, thereby decreasing marketable bulb size and yield.

Although drought and wet injury differ in their manifestations, both disrupt the physiological basis required for yield formation in F. thunbergii. Drought mainly reduces dry matter accumulation by lowering water supply, inducing stomatal closure, and limiting photosynthetic capacity, whereas waterlogging affects plant growth mainly by inhibiting root respiration, damaging the rhizosphere environment, obstructing nutrient uptake, and aggravating disease. In field studies on industrial hemp, both severe drought and waterlogging caused by excessive water reduced photosynthesis and decreased plant growth and yield by more than 50%, with only partial recovery after stress relief (Kumar et al., 2025). This further demonstrates that both excessively dry and excessively wet conditions can cause productivity losses. For F. thunbergii, cultivation should avoid large fluctuations in water supply, especially problems such as drought in the early stage affecting emergence, water shortage in the middle stage limiting growth, and waterlogging in the late stage causing rot. A stable, moderate, and well-coordinated irrigation and drainage environment is an important condition for ensuring stable yield in F. thunbergii.

4.3 Effects of rational water regulation on peimine accumulation and quality stability

Water conditions not only affect yield formation in F. thunbergii, but also influence the accumulation of secondary metabolites such as peimine. The synthesis and accumulation of peimine depend on normal physiological metabolism, while water supply affects photosynthesis, nutrient uptake, carbon-nitrogen metabolism, intracellular metabolic balance, and stress signal transduction. Appropriate soil moisture can maintain strong photosynthetic capacity and a relatively stable growth state, providing a material basis for peimine biosynthesis. If water is insufficient or excessive, normal plant metabolism may be disrupted, leading to unstable accumulation of active components and affecting medicinal quality. Studies on related medicinal plants have shown that moderate water deficit can sometimes increase alkaloids or other secondary metabolites, whereas severe stress leads to decreased biomass and quality fluctuations. For example, in summer snowflake (Leucojum aestivum), moderate water deficit stress, namely 50% deficit irrigation, resulted in higher levels of bulb alkaloids such as galanthamine and lycorine, as well as phenolic compounds and antioxidant capacity, whereas severe stress or waterlogging reduced fresh weight and did not further increase alkaloid content (Baba et al., 2024).

Moderate water regulation helps achieve coordinated improvement of yield and quality. In the early growth stage of F. thunbergii, soil should be kept moderately moist to promote sprouting, emergence, and root formation. During vegetative growth and bulb enlargement, stable water supply should be ensured to avoid premature leaf senescence caused by water shortage. In the late growth stage and before harvest, water should be appropriately controlled according to soil conditions and weather changes to reduce waterlogging and disease occurrence and promote bulb maturation and filling. Studies on Atractylodes chinensis have shown that moderate irrigation levels can maintain relatively high yield while maximizing alkaloid-related enzyme activities and quality indicators; the quality peak occurs at an intermediate irrigation level rather than under maximum water supply (Lv et al., 2026). In Datura stramonium, gradient irrigation creates different tropane alkaloid profiles in different organs, indicating that soil water supply can serve as a cultivation measure for regulating the accumulation of specific alkaloids (Moreno-Pedraza et al., 2019). These studies provide insights for water regulation in F. thunbergii: controlled and non-severe mild water deficit may help enhance peimine accumulation, provided that bulb biomass and marketability are not significantly sacrificed.

In production practice, water regulation should be integrated with soil improvement, ridge and ditch construction, disease control, and water-fertilizer coordinated management. Selecting well-drained fields, adopting high-ridge cultivation, improving ditch drainage systems, applying mulching for moisture conservation, and conducting scientific irrigation according to rainfall conditions can all help maintain suitable soil moisture. Reviews on drought and medicinal plant physiology indicate that mild to moderate stress usually stimulates the formation of secondary metabolites such as phenols, flavonoids, and alkaloids, whereas severe or prolonged stress leads to yield collapse and unstable quality (Bistgani et al., 2024; Tan and Gören, 2024). Studies combining water and nutrient management have also shown that under 70%~75% of maximum water-holding capacity combined with moderate nitrogen supply, Sophora alopecuroides can achieve relatively high biomass and alkaloid accumulation while promoting the formation of specific rhizosphere microbial communities (Huang et al., 2024b). Therefore, for F. thunbergii, water management should avoid long-term drought and frequent waterlogging, with stable soil moisture close to field capacity as the basic goal. After experimental verification, short-term, precise, and mild water deficit treatments may be explored to promote peimine accumulation. Establishing a management system centered on soil moisture monitoring, rational irrigation and drainage, and rhizosphere environment optimization can improve yield stability and consistency of peimine content in F. thunbergii, thereby providing support for the production of high-quality medicinal materials.

5 Effects of Soil Environment on the Yield of Fritillaria thunbergii and Peimine Accumulation

5.1 Relationship among soil texture, aeration, and bulb development

Soil is an important medium for root growth, bulb enlargement, and active constituent accumulation in Fritillaria thunbergii, and its texture and structure directly affect the development of underground organs. Since the bulb is the medicinal part of F. thunbergii, whether the underground part can fully enlarge is closely related to soil looseness, pore distribution, water and nutrient retention capacity, and mechanical resistance. Soil texture determines pore size distribution, aeration, and water-holding capacity, thereby influencing root penetration capacity and the supply of carbohydrates to underground storage organs. Relevant meta-analyses have shown that coarse sandy soils drain rapidly but have weak nutrient retention capacity, whereas heavy clay soils have stronger water and nutrient retention capacity but are prone to poor aeration and waterlogging. Loamy soils with appropriate proportions of sand, silt, and clay usually balance aeration, water retention, and fertility, making them more favorable for crop productivity (Bhatt et al., 2025). Therefore, for bulbous medicinal plants such as F. thunbergii, deep, loose, well-aggregated loamy soils with good drainage are more conducive to root extension, assimilate transport, and continuous bulb enlargement. In contrast, overly heavy, compacted, or extremely sandy soils may restrict bulb development due to excessive root penetration resistance, rhizosphere waterlogging, or insufficient water and nutrient retention.

Soil aeration is an important factor affecting the physiological activities of the underground parts of F. thunbergii. Roots and bulbs require normal respiration during growth to maintain cellular metabolism, energy supply, and nutrient absorption. Well-aerated soil can ensure oxygen supply in the rhizosphere, promote root vitality and nutrient absorption efficiency, and reduce the risk of root diseases. Conversely, poorly drained soils, low porosity, or long-term excessive moisture easily create hypoxic conditions, inhibiting root respiration and leading to root weakness, bulb rot, and pathogen proliferation. Studies on crops such as maize and tomato have shown that soil aeration-enhancing technologies, including aerated seepage irrigation and micro/nano-bubble systems, can increase soil oxygen content, soil respiration, microbial biomass, root length, and root surface area, and significantly improve yield. At the same time, soil aeration can also increase the activities of nutrient-cycling enzymes such as urease, thereby enhancing nitrogen transformation and the supply of available nutrients to roots (Li et al., 2022; Yu et al., 2024). These findings suggest that good soil aeration not only directly affects root respiration, but also indirectly promotes the development of underground storage organs by regulating microbial activity and nutrient cycling.

In production practice, priority should be given to selecting fields with loose and fertile soil, convenient irrigation and drainage, and good soil permeability for F. thunbergii cultivation. During land preparation, deep plowing and soil exposure, high-ridge cultivation, and the application of well-decomposed organic fertilizer can be used to improve soil aggregate structure, reduce compaction, and enhance the coordination between water retention and drainage. Heavy clay soils or low-lying waterlogged fields should be avoided for large-scale continuous cultivation of F. thunbergii, or the rhizosphere environment should be improved through ditch drainage, soil replacement or amendment, increased organic matter input, and improved irrigation and drainage systems. In highly moist or compacted soils, limited oxygen diffusion reduces root respiration and nutrient absorption capacity and promotes root diseases. Even when nutrient inputs are sufficient, poor aeration may restrict fertilizer effectiveness (Yang et al., 2025). Given that F. thunbergii bulbs are sensitive to rot and require a relatively high oxygen supply in the rhizosphere, maintaining suitable soil structure and aeration is an important basis for supporting healthy bulb development, stable yield, and peimine accumulation.

5.2 Effects of soil fertility and ph on nutrient absorption and yield formation

Soil fertility is directly related to nutrient supply and yield formation in F. thunbergii. During growth, F. thunbergii needs to absorb nitrogen, phosphorus, potassium, and various medium and trace elements from the soil to support leaf establishment, root development, and bulb enlargement. Nitrogen promotes vegetative growth and leaf formation, phosphorus contributes to root development and energy metabolism, and potassium is closely associated with assimilate transport, stress resistance, and bulb filling. Studies on fertilization in medicinal crops have shown that yield responses to nutrient inputs depend largely on soil properties and climatic context. Long-term high fertilizer input or unfavorable water conditions may increase biomass in the short term, but may also weaken medicinal quality (Yang et al., 2025). A systematic review of nitrogen management in medicinal plants further indicated that moderate nitrogen application generally improves both yield and plant metabolite content, whereas excessive nitrogen reduces quality and may even suppress yield (Hao et al., 2024). This suggests that fertilization in F. thunbergii should not simply pursue high input, but should provide balanced nutrients according to the soil fertility basis and growth-stage requirements.

Soil nutrient supply should remain coordinated, rather than focusing excessively on a single nutrient or fertilizer type. Excessive nitrogen application may lead to excessive aboveground vegetative growth, tender plant tissues, reduced disease resistance, and impaired assimilate accumulation in bulbs. Insufficient phosphorus and potassium supply, meanwhile, can restrict root development, energy metabolism, assimilate transport, and bulb filling. Studies on bulbous medicinal plants such as Pinellia ternata have shown that phosphorus application alone can increase bulbil biomass by 43%, while combined phosphorus and potassium fertilization can double biomass compared with the unfertilized control, highlighting the importance of balanced macronutrient supply for the development of underground storage organs (Ng et al., 2023). Therefore, for F. thunbergii, organic fertilizer should be used as the basis, combined with appropriate supplementation of nitrogen, phosphorus, potassium, and medium and trace elements, while emphasizing coordination among vegetative growth, bulb enlargement, and active constituent formation. Long-term improper fertilization may also lead to salt accumulation, aggravated soil acidification, and microbial community imbalance, further affecting the growth and medicinal quality of F. thunbergii.

Soil pH affects nutrient availability, root vitality, microbial activity, and photosynthetic performance, and is one of the important factors determining the ecological suitability of F. thunbergii. Excessively acidic or alkaline environments may reduce the availability of certain mineral elements, impair root absorption capacity, and induce nutrient imbalance. In medicinal plants such as Melissa officinalis, Taraxacum officinalis, and Ocimum basilicum, germination, growth, and photosynthetic efficiency are significantly affected by soil pH, and pH changes also alter the uptake of micronutrients such as manganese, copper, and zinc (Adamczyk-Szabela and Wolf, 2022). Studies on continuous cropping obstacles further emphasize that pH and cation exchange capacity are key factors determining soil biochemical and biological properties, and they can regulate microbial community structure and nutrient accessibility. Under continuous cropping conditions, soil acidification or alkalization can intensify nutrient imbalance and weaken root nutrient absorption capacity (Haq et al., 2023; Li et al., 2024). Therefore, in production, soil pH can be regulated through soil testing and formula fertilization, increasing organic matter, and rational application of lime or soil conditioners, so that nitrogen, phosphorus, potassium, and trace elements remain highly available while beneficial microbial activity is promoted, thereby providing a stable soil chemical environment for yield formation and peimine biosynthesis in F. thunbergii.

5.3 Effects of soil microecology and continuous cropping obstacles on peimine accumulation

Soil microecology is an important hidden factor affecting the healthy growth and quality formation of F. thunbergii. Rhizosphere microorganisms participate in organic matter decomposition, nutrient transformation, pathogen suppression, and plant stress regulation, playing important roles in root growth, bulb development, and secondary metabolite formation. A healthy soil microecology can improve soil nutrient cycling efficiency, promote root uptake of nutrients and water, and enhance plant adaptability to unfavorable environments. In F. thunbergii cultivation, organic fertilizer can significantly reshape fungal communities by increasing saprotrophic fungal groups such as Pezizales and Sordariales, reducing the proportion of pathotrophic fungi, enhancing enzyme activities, lowering the soil NH₄⁺/NO₃⁻ ratio, and increasing bulb yield by nearly sevenfold compared with the unfertilized control (Du et al., 2024). This shift toward beneficial saprotrophic fungal communities is associated with improved soil health and nutrient turnover capacity, and may help support both biomass formation and the accumulation of alkaloids such as peimine in F. thunbergii. Broader studies have also shown that beneficial microorganisms can enhance stress resistance, suppress pathogens, improve nutrient absorption, and regulate secondary metabolite biosynthesis in medicinal plants, making them environmentally friendly tools for improving medicinal material quality (Wang et al., 2022).

Continuous cropping obstacles are common in F. thunbergii cultivation. Long-term continuous planting in the same field can easily lead to imbalanced soil nutrient ratios, soil acidification or alkalization, accumulation of harmful root exudates and autotoxic substances, increased pathogens, and reduced beneficial microorganisms, thereby disrupting the balance of rhizosphere microecology (Haq et al., 2023). Continuous cropping obstacles not only reduce emergence rate, weaken plant growth, and aggravate disease, but also affect bulb development and active constituent accumulation. Studies on other medicinal plants can provide references for F. thunbergii. For example, in long-term monoculture systems of Codonopsis pilosula, soil total phosphorus and available potassium increased, whereas pH decreased, bacterial diversity declined, and autotoxic compounds such as 2,6-di-tert-butylphenol accumulated. These changes were associated with declines in yield and quality (Li et al., 2024). Reviews focusing on the rhizosphere of medicinal plants have pointed out that autotoxic substances and pH shifts can disrupt microbial structural stability, reducing beneficial microorganisms while increasing harmful microorganisms, thereby impairing nutrient acquisition and secondary metabolite profiles (Liao and Xia, 2024). Although direct data on changes in peimine under continuous cropping conditions in F. thunbergii remain limited, it can be inferred that soil microecological degradation, increased pathogens, and intensified chemical stress may interfere with steroidal alkaloid biosynthesis and regulation, leading to fluctuations in medicinal quality.

Improving soil microecology and alleviating continuous cropping obstacles are important directions for enhancing yield and quality stability in F. thunbergii. In production, soil-borne disease pressure can be reduced and soil microbial diversity restored through rational crop rotation, intercropping, application of well-decomposed organic fertilizer and microbial fertilizer, removal of diseased residues, and necessary soil disinfestation and ecological restoration. Meanwhile, excessive use of chemical fertilizers and pesticides should be reduced to avoid further disruption of the rhizosphere ecological environment. Studies have shown that crop rotation, organic amendments, and targeted microbial inoculation have demonstrated potential in other medicinal plants to restore microbial balance, alleviate continuous cropping obstacles, and increase secondary metabolite levels (Wang et al., 2022; Haq et al., 2023; Li et al., 2024). By constructing a healthy and stable soil microecological system, it is possible not only to improve stress resistance and bulb yield in F. thunbergii, but also to promote stable peimine content, thereby supporting the production of high-quality geo-authentic medicinal materials.

6 Effects of Regional Ecological Conditions and Cultivation Patterns on Quality Formation in Fritillaria thunbergii

6.1 Effects of altitude and production-area ecological environment on the growth of Fritillaria thunbergii

Regional ecological conditions constitute an important external basis affecting the growth, development, and quality formation of Fritillaria thunbergii. Different production areas vary in altitude, air temperature, precipitation, light, diurnal temperature difference, soil type, and field moisture conditions. Together, these factors determine the growth rhythm, degree of bulb enlargement, and level of active constituent accumulation in F. thunbergii. The suitable distribution of Fritillaria species is clearly constrained by macroecological factors. Jiang et al. (2022) modeled the potential geographical distribution of three Fritillaria species and found that precipitation, altitude, and temperature were the dominant variables determining suitable habitats. In particular, annual precipitation below approximately 336 mm significantly reduced the probability of occurrence. Suitable precipitation around the sowing period, namely September to October, and during the bulb filling period, namely May, was especially important for seed germination, early growth, and nutrient accumulation, whereas imbalanced water supply increased the risk of disease (Jiang et al., 2022). Therefore, for F. thunbergii, ecological suitability evaluation should not focus on a single climatic factor alone, but should comprehensively analyze the matching relationships among temperature, precipitation, light, soil drainage, and disease pressure.

Altitude changes affect the growth of F. thunbergii by regulating temperature, light intensity, air humidity, and diurnal temperature difference. A relatively suitable altitude environment usually provides mild or cool climatic conditions, which can delay aboveground senescence to some extent, prolong the photosynthetic functional period of leaves, and allow more assimilates to be transported to the underground bulbs. Meanwhile, an appropriate diurnal temperature difference helps reduce nighttime respiratory consumption and promotes dry matter accumulation and bulb filling. A review on the taxonomy and cultivation of Fritillaria species indicated that biomass and morphology change systematically with altitude: Fritillaria species growing at high altitudes, namely 2 700~4 000 m, are usually shorter and single-flowered, whereas species distributed below 1 500 m tend to be taller, multi-flowered, and have greater biomass. Altitude also changes together with thermal regime and solar radiation, thereby regulating plant height, phenology, and the skeleton types of isosteroidal alkaloids (Qu et al., 2022). This indicates that higher altitude is not necessarily more favorable. If temperature is too low or the growing season is too short, sprouting, leaf expansion, and bulb enlargement may also be restricted.

The ecological environment of the production area also affects the quality stability of F. thunbergii. Interannual climatic variation, soil fertility basis, and field management conditions differ among regions, which may lead to differences in peimine content and bulb marketability. Existing studies show that F. thunbergii is usually cultivated in mid- to low-altitude areas, such as Pan’an County in Zhejiang Province at an altitude of approximately 600 m. The warm and humid monsoon climate and relatively favorable soil fertility in this region are conducive to vigorous plant growth and high bulb productivity (Huang et al., 2024a). For F. thunbergii production, selecting production areas with stable ecological environments, suitable soil conditions, and low disease pressure is beneficial for achieving high and stable yield and quality. Therefore, evaluating production-area ecological factors and defining suitable cultivation regions are important prerequisites for promoting standardized production and quality control of F. thunbergii.

6.2 Environmental characteristics of geo-authentic production areas and quality advantages of Fritillaria thunbergii

As a traditional geo-authentic medicinal material of Zhejiang Province, the quality advantages of F. thunbergii are closely associated with the long-established ecological environment of its production areas. Geo-authentic production areas usually possess suitable climatic conditions, soil types, rhizosphere microecology, and cultivation experience. These factors together shape a relatively stable growth environment and quality characteristics for F. thunbergii. Suitable temperature and humidity conditions meet the ecological requirements of F. thunbergii, which prefers cool and moist conditions but is intolerant of waterlogging. Good soil structure supports root growth and bulb enlargement, while mature cultivation management techniques further guarantee medicinal material yield and commercial quality. Shi et al. (2011) compared three major production areas, namely the Ningbo geo-authentic production area, Pan’an, and Nantong, and found that soil pH ranged from 4.48 to 7.73 across different regions, indicating that F. thunbergii can tolerate acidic to slightly alkaline soil conditions. Among them, Ningbo, as the geo-authentic production area, had the highest soil organic matter content, phosphatase activity, and urease activity, reflecting superior soil fertility and enzyme activity (Shi et al., 2011).

The advantages of geo-authentic production areas are reflected not only in natural ecological conditions, but also in cultivation systems and quality awareness formed through long-term production practice. Growers can usually arrange sowing, fertilization, irrigation and drainage, shading, and harvesting reasonably according to local climatic changes and soil characteristics, enabling F. thunbergii to obtain suitable environmental conditions during key growth stages. This coordinated relationship among “ecological environment-cultivation technology-medicinal material quality” is an important basis for the formation of geo-authentic medicinal quality. It is worth noting that geo-authentic areas are not the only spaces where quality can form. Shi et al. (2011) showed that Nantong, a non-geo-authentic production area with relatively alkaline soil, had higher rhizobacterial diversity and bulb alkaloid content, suggesting that alkaline pH and abundant microbial communities may also favor secondary metabolite accumulation. This indicates that both geo-authentic areas and high-quality non-geo-authentic areas may possess favorable soil nutrient status, active microbial processes, and suitable ecological environments, jointly shaping bulb quality.

From the perspective of quality formation, geo-authentic production areas provide a relatively stable environment for material accumulation and secondary metabolism in F. thunbergii. Within Zhejiang Province, the soil properties of Pan’an and Ningbo are relatively similar, which provides a practical basis for large-scale cultivation of F. thunbergii in Pan’an while maintaining quality comparable to that of the geo-authentic area (Shi et al., 2011; Huang et al., 2024a). Multi-regional LC-MS chemometric studies further found that F. thunbergii bulbs produced in Zhejiang differed significantly in alkaloid profiles from samples from other provinces. Through targeted quantification of key alkaloids and non-targeted analysis, Zhejiang-produced bulbs could be distinguished from non-Zhejiang samples, and 11 characteristic markers associated with bulb appearance traits were identified (Zhang et al., 2026). This indicates that geo-authentic ecological conditions not only affect the external morphology of F. thunbergii, but also confer specific alkaloid fingerprints. In the future, based on the protection of traditional production-area advantages, ecological suitability evaluation, metabolomics, and modern quality testing technologies should be combined to further clarify the relationships between environmental factors in geo-authentic areas and peimine accumulation, thereby providing a basis for quality improvement and origin authentication of F. thunbergii.

6.3 Effects of open-field cultivation, understory cultivation, facility cultivation, and other patterns on yield and quality

Open-field cultivation is a relatively common production pattern for F. thunbergii, with the advantages of relatively simple management, low production cost, and suitability for large-scale cultivation. In suitable production areas and under good field management conditions, open-field cultivation can meet the basic growth requirements of F. thunbergii and produce relatively stable bulb yield. Traditional open-field cultivation of F. thunbergii in areas such as Pan’an mainly depends on local climatic conditions and fertilization management, while optimized organic fertilizer application and potassium fertilization have been shown to simultaneously increase bulb yield and peimine content (Sui et al., 2021; Huang et al., 2024a). However, open-field cultivation is highly dependent on natural climate and is vulnerable to strong light, high temperature, continuous rainfall, drought, and disease. Without effective shading, drainage, and soil management measures, premature senescence of aboveground parts, poor bulb development, or quality fluctuations may occur. Therefore, open-field cultivation should focus on coordinated management of light, temperature, water, and fertilizer, as well as disease control. Especially in years with large climatic fluctuations, cultivation stability should be improved through shading, water-fertilizer regulation, and drainage measures.

Understory cultivation and semi-wild cultivation patterns can improve the growth environment of F. thunbergii to some extent. Understory environments are characterized by moderate shading, buffered temperature changes, higher air humidity, richer soil organic matter, and more complex microbial communities. These conditions help alleviate strong light and high-temperature stress, prolong the functional period of leaves, and create a relatively stable ecological environment for bulb enlargement and active constituent accumulation. Reviews on understory cultivation indicate that the lower light intensity, buffered temperature and humidity, altered soil fertility, and microbial communities in understory environments may significantly increase or decrease the yield and quality of medicinal plants compared with open-field cultivation, depending on species characteristics and stand structure (Li et al., 2025; Wen et al., 2025). For F. thunbergii, understory cultivation combined with soil amendments such as organic fertilizer and biochar can optimize soil and rhizosphere microecology, helping improve bulb yield and alkaloid quality compared with traditional cultivation patterns (Liu et al., 2026). However, understory or semi-wild patterns also have limitations, such as greater management difficulty, larger yield fluctuations, and limited mechanization. Therefore, refined regulation should be carried out according to forest stand type, canopy closure, soil conditions, and water status.

Facility cultivation provides a new approach for precise environmental regulation in F. thunbergii. Through temperature and humidity control, shading management, water-fertilizer regulation, and disease control under facility conditions, the adverse effects of extreme weather on production can be reduced, while emergence uniformity, plant growth stability, and yield controllability can be improved. Studies on other medicinal plants help explain the mechanisms of different cultivation patterns. For example, in Epimedium pubescens, inter-row understory cultivation under different tree species can produce yields and active constituent contents comparable to or higher than open-field controls when microclimatic conditions such as air humidity are suitable, whereas excessive shading under dense canopies reduces yield (Li et al., 2026). Shading experiments and agroforestry studies on aromatic and medicinal plants have also shown that mild to moderate shading, approximately 30%~40%, usually slightly reduces biomass but can increase essential oil or active constituent contents; heavy shading, exceeding 50%~75%, significantly reduces yield and does not necessarily bring further quality improvement (Zubay et al., 2021; Şeker et al., 2023). Therefore, different cultivation patterns each have advantages and limitations. They should be selected according to production-area conditions, production goals, and cost effectiveness. Guided by ecological and omics data, the advantages of open-field cultivation, understory cultivation, and facility cultivation should be integrated to construct standardized production patterns that balance high bulb yield, high peimine content, and ecological sustainability.

7 Mechanistic Analysis of Cultivation Environment Regulation of Yield and Peimine Accumulation in Fritillaria thunbergii

7.1 Regulatory mechanisms of environmental factors on photosynthesis and dry matter accumulation

The basis of yield formation in Fritillaria thunbergii lies in plant photosynthesis, carbon assimilation, and dry matter accumulation, which are jointly affected by environmental factors such as light, temperature, water, soil fertility, and the root-zone environment. Leaves are the main organs for photosynthesis in F. thunbergii. Appropriate light can improve leaf light-use efficiency and promote organic matter synthesis, while suitable temperature helps maintain enzyme activity and cellular metabolism, allowing plants to sustain strong physiological activity. Existing studies have shown that, in F. thunbergii, shading within a certain range reduces the net photosynthetic rate, but plants can partially compensate by increasing chlorophyll content and adjusting leaf traits. However, excessive shading markedly inhibits biomass accumulation and bulb yield (Liu et al., 2025a). Meanwhile, appropriate potassium fertilization under shading conditions can alleviate the decline in bulb biomass, indicating that improved mineral nutrition can partially restore photosynthetic capacity and carbon fixation. Studies on other medicinal plants have also shown that moderate nitrogen application or balanced nitrogen, phosphorus, and potassium supply can optimize leaf dry weight, total biomass, and photosynthetic rate, whereas nitrogen deficiency or excessive nitrogen application may reduce photosynthesis by limiting chlorophyll formation, inducing reactive oxygen species damage, or downregulating photosynthetic antenna-related genes (Yang et al., 2024). Therefore, the influence of environmental factors on the yield of F. thunbergii is first reflected in the regulation of leaf photosynthetic carbon capture capacity.

The transport of dry matter from the aboveground parts to the underground bulbs is a key process in yield formation in F. thunbergii. During the vegetative growth stage, plants synthesize carbohydrates through leaves and use them for stem and leaf growth, root development, and bulb filling. After entering the bulb enlargement stage, assimilates are gradually transferred to the underground parts, and the bulbs become the main storage organs. At this stage, the stability of environmental conditions directly determines the efficiency of dry matter accumulation. Suitable soil moisture and nutrient supply can enhance root absorption capacity and maintain continuous photosynthesis in the aboveground parts, while good soil aeration supports root respiration and energy metabolism, thereby promoting the transport of assimilates to the bulbs. Temperature and root-zone conditions also regulate photosynthetic performance and biomass formation. Studies on hydroponically grown medicinal plants have shown that air temperature and root-zone temperature significantly affect photosynthesis, nutrient uptake, leaf growth, and secondary metabolite accumulation. Unsuitable temperatures can induce oxidative stress and reduce water uptake, whereas appropriate temperatures promote growth and metabolite formation (Venkatasai et al., 2025). Metabolomics-based stress studies have further shown that abiotic factors such as drought, salinity, extreme temperature, and pH can alter the levels of primary metabolites, including amino acids and carbohydrates. These substances function as osmotic regulators and energy reserves under stress conditions and also reflect adjustments in photosynthetic carbon flow and respiratory metabolism (Salam et al., 2023).

Different environmental factors do not act in isolation, but influence yield by comprehensively regulating plant growth status. For example, moderate shading can reduce strong light and high-temperature stress and delay premature leaf senescence; rational water and fertilizer management can maintain the functional period of leaves and enhance root vitality; and good soil structure can improve water and nutrient use efficiency. Only when light, temperature, water, fertilizer, and aeration conditions are coordinated can F. thunbergii establish a stable vegetative growth foundation and accumulate more dry matter in the bulbs. Therefore, the mechanism by which environmental factors regulate yield is essentially realized through their effects on photosynthesis, carbon assimilation, root absorption, assimilate transport, and bulb storage processes. At the same time, these primary metabolic processes also provide carbon skeletons and energy for the biosynthesis of steroidal alkaloids such as peimine.

7.2 Induction mechanisms of environmental stress on secondary metabolism and peimine biosynthesis

Peimine is an important steroidal alkaloid secondary metabolite in F. thunbergii, and its formation is closely related to plant growth status and environmental responses. Plant secondary metabolism is usually associated with defense, adaptation, and stress resistance. When plants are exposed to a certain degree of environmental stimulation, corresponding metabolic regulatory mechanisms may be activated, promoting the synthesis and accumulation of active components such as alkaloids, terpenoids, flavonoids, and phenylpropanoids. Extensive studies have shown that light intensity and quality, temperature, soil moisture, fertility, and salinity can significantly increase or decrease plant secondary metabolite levels, and different types of stress often induce the accumulation of different classes of compounds (Yang et al., 2018; Pant et al., 2021; Qaderi et al., 2023). Therefore, changes in peimine accumulation in F. thunbergii can be understood as the result of the combined regulation of primary metabolism, stress signaling, and secondary metabolic pathways by environmental factors.

Under abiotic stress conditions, plants usually activate a series of signal transduction processes, including reactive oxygen species, phytohormones such as jasmonic acid, abscisic acid, and salicylic acid, Ca²⁺ signaling, and mitogen-activated protein kinase (MAPK) cascades. These signals further converge on transcription factors such as MYB, bHLH, AP2/ERF, WRKY, bZIP, and NAC, which coordinately upregulate or downregulate biosynthetic genes in alkaloid, terpenoid, and phenylpropanoid pathways (Kajla et al., 2023; Rabeh et al., 2025). Metabolomics studies have also confirmed that stress-induced changes in primary metabolism, such as alterations in the shikimate pathway, terpenoid backbone pathway, and amino acid metabolism, can further provide precursors, energy, and metabolic flux for the formation of nitrogen-containing alkaloids and other defensive secondary metabolites (Salam et al., 2023). Therefore, moderate environmental stress may promote peimine biosynthesis through a chain reaction involving “signal activation-transcriptional regulation-metabolic pathway redistribution.”

In F. thunbergii, existing omics studies have provided direct evidence for this mechanism. The combined treatment of shading and potassium fertilization can significantly increase the contents of peimine, peiminine, imperialine, and other steroidal alkaloids in bulbs. Transcriptomic analysis has identified multiple upregulated genes in the terpenoid/steroidal alkaloid pathway, among which farnesyl pyrophosphate synthase (FtFPS) is regarded as a key hub gene. FtFPS catalyzes the formation of farnesyl pyrophosphate, which is an important precursor for sterol and steroidal alkaloid biosynthesis. Meanwhile, FtFPS can interact with AP2/ERF transcription factors, thereby linking external environmental signals with the activation of the steroidal alkaloid pathway (Liu et al., 2025a). Another fertilization study on F. thunbergii showed that organic fertilizer can increase the contents of peimine and peiminine, possibly through the upregulation of ABA signaling and the induction of putative genes related to steroidal alkaloid biosynthesis (Huang et al., 2024a). Therefore, environmental stress has a dual effect on peimine biosynthesis: moderate stimulation can act as an inducing signal to activate secondary metabolic pathways, whereas excessive stress may inhibit growth, reduce photosynthetic carbon supply, and cause metabolic disorder, ultimately leading to unstable accumulation of active constituents.

7.3 Coordination mechanisms between yield formation and peimine accumulation

The goal of F. thunbergii production is not only to increase bulb yield, but also to ensure the content of active constituents such as peimine. Therefore, it is necessary to correctly understand the relationship between yield formation and quality formation. Yield mainly depends on photosynthesis, dry matter accumulation, and bulb enlargement, while peimine accumulation is closely associated with secondary metabolic activity. The two processes are both consistent and potentially contradictory. A favorable growth environment can improve plant vigor and bulb yield while providing sufficient substrates for peimine biosynthesis. However, if the environment excessively promotes vegetative growth, dry matter allocation and metabolic direction may shift toward biomass expansion, and active constituent accumulation may not increase synchronously. Studies have shown that shading alone can significantly increase the total active ingredient content in F. thunbergii bulbs, but it reduces bulb biomass and yield, showing a typical “high-quality/low-yield” pattern (Liu et al., 2025a).

The coordination between yield and peimine accumulation depends on regulating the growth focus and metabolic allocation of plants at different developmental stages. In the early growth stage, priority should be given to promoting sprouting, leaf expansion, and root establishment, thereby laying the foundation for subsequent material accumulation. During the vegetative growth stage, high photosynthetic efficiency and moderate population growth should be maintained to ensure sufficient assimilate supply. During bulb enlargement and maturation, dry matter transfer to the underground bulbs should be promoted, while suitable light, temperature, water, and soil conditions should be maintained to support secondary metabolic activity. Existing studies have shown that when shading is combined with appropriate potassium fertilization, yield loss in F. thunbergii can be alleviated while peimine and related steroidal alkaloids remain at relatively high levels. Moreover, antitussive, expectorant, and anti-inflammatory activities are relatively optimal under moderate potassium treatment (Liu et al., 2025a). Similarly, organic fertilizer treatment can achieve relatively high bulb yield while increasing peimine and peiminine contents, indicating that an appropriate nutrient regime can shift the system from a strict yield-quality trade-off toward a more coordinated outcome (Huang et al., 2024a).

Mechanistic studies on other medicinal plants also support this coordination strategy. Moderate resource supply can generally optimize carbon-nitrogen balance and carbon allocation, thereby promoting both biomass and secondary metabolite accumulation. For example, in Epimedium pubescens, moderate nitrogen treatment can produce relatively high total dry weight and higher levels of icariin-type flavonoids, whereas both low and high nitrogen weaken photosynthesis, disrupt carbon-nitrogen homeostasis, reduce soluble sugar and starch contents, and suppress flavonoid biosynthesis (Liu et al., 2025b). Reviews on medicinal plant cultivation have also pointed out that environmental factors such as temperature, light, soil fertility, and water need to be precisely controlled to stabilize secondary metabolite content and yield. At the same time, harvest timing should be regulated so that the peak of secondary metabolite accumulation coincides with an acceptable biomass level, thereby achieving the so-called “optimal harvest time” (Yang et al., 2018; Qaderi et al., 2023). By extension, scientific environmental management for F. thunbergii should aim at the coordinated improvement of yield and quality. Through ecological suitability zoning, moderate shading, rational water and fertilizer supply, soil improvement, rotation and intercropping, and disease control, a stable and suitable growth environment can be constructed. On this basis, incorporating bulb yield, marketable traits, dry matter content, peimine content, and safety indicators into comprehensive evaluation will help establish a more scientific cultivation technology system for F. thunbergii and achieve coordinated development of medicinal material yield, quality, and industrial benefits.

8 Future Perspectives and Prospects

High-quality and high-yield production of Fritillaria thunbergii should first be based on the selection of ecologically suitable areas. Since F. thunbergii prefers cool, moist, and well-ventilated environments and is intolerant of high temperature and waterlogging, cultivation areas should preferably be selected in regions with a mild climate, appropriate diurnal temperature difference, relatively balanced precipitation, loose and fertile soil, and favorable irrigation and drainage conditions. The screening of ecologically suitable areas should not rely solely on traditional cultivation experience, but should comprehensively consider factors such as altitude, temperature, light, precipitation, soil texture, pH, disease risk, as well as transportation and processing conditions, so as to form a regionalized cultivation layout. On this basis, standardized cultivation strategies should be promoted, including the selection of high-quality seed bulbs, seed source grading, pre-sowing treatment, rational close planting, scientific fertilization, green pest and disease control, and timely harvesting. By establishing unified production technical procedures and field management standards, differences in management among growers can be reduced, thereby improving yield stability and quality consistency of F. thunbergii and laying a foundation for geo-authentic medicinal material brand development and industrial-scale production.

The core of cultivation environment optimization for F. thunbergii lies in the comprehensive coordination of light, temperature, water, fertility, and soil conditions. In production, refined management should be carried out according to the requirements of different growth stages. During sprouting and emergence, soil should be kept moderately moist with good aeration to promote uniform emergence and root formation. During vegetative growth, moderate shading, rational irrigation, and balanced fertilization should be used to maintain leaf photosynthetic function and promote assimilate accumulation. During bulb enlargement, stable water and fertilizer supply should be emphasized, while premature senescence of aboveground parts caused by high temperature, drought, or wet injury should be avoided. In the late growth stage, water should be appropriately controlled to promote bulb maturation and stable accumulation of active constituents. In fertilizer management, the principle of using organic fertilizer as the basis, applying chemical fertilizers appropriately, and reasonably supplementing medium and trace elements should be followed, while avoiding excessive nitrogen application or overfertilization that may cause excessive vegetative growth and soil degradation. Meanwhile, measures such as deep plowing and soil exposure, high-ridge cultivation, application of well-decomposed organic fertilizer, crop rotation and intercropping, use of microbial fertilizers, and construction of drainage systems should be adopted to improve soil structure and rhizosphere microecology, alleviate continuous cropping obstacles, reduce the risk of soil-borne diseases, and provide a favorable environment for peimine accumulation and medicinal quality stability.

In the future, the development of the F. thunbergii industry should shift from a single yield-oriented approach toward the coordinated improvement of yield and quality. When evaluating cultivation effects, attention should be paid not only to yield per unit area, single-bulb weight, and commercial appearance, but also to dry matter content, contents of active constituents such as peimine and peiminine, incidence of pests and diseases, pesticide residues, heavy metal safety, and environmental parameters of the production area. By establishing an evaluation model integrating “environmental factors-growth indicators-yield indicators-quality indicators,” the comprehensive effects of different cultivation environments and management measures on the overall quality of F. thunbergii can be more accurately reflected. Future research should further strengthen studies on the physiological and molecular mechanisms by which cultivation environment regulates peimine biosynthesis, and clarify the effects of light, temperature, water, fertilizer, soil microecology, and environmental stress on peimine metabolic pathways. Meanwhile, the application of digital monitoring, precise water and fertilizer management, facility cultivation, ecological cultivation, and quality traceability technologies in F. thunbergii production should be promoted. Through the integration of basic research and production practice, high-quality and high-yield cultivation patterns suitable for different production areas can be gradually established, thereby promoting the standardized, green, and high-quality development of the F. thunbergii industry.

Conflict of Interest Disclosure

The authors affirm that this research was conducted without any commercial or financial relationships that could be construed as a potential conflict of interest.

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