1 Introduction

Tetrastigma hemsleyanum Diels et Gilg is a perennial climbing vine of the genus Tetrastigma in the family Vitaceae and is one of the important traditional medicinal plant resources in China. Commonly known as “Sanyeqing”, it is regarded as a “plant antibiotic” because of its broad medicinal activities (Ji et al., 2020; Hu et al., 2021). Its main medicinal part is the tuberous root, while the whole plant is also used medicinally in some regions. In folk and clinical applications, it is commonly used as an adjuvant treatment for diseases such as high fever in children, pneumonia, hepatitis, gastritis, rheumatism, sore throat, lymphatic tuberculosis, and viral meningitis. Modern pharmacological and phytochemical studies have shown that the tuberous roots and aerial parts of T. hemsleyanum contain various active compounds, including flavonoids, polysaccharides, phenolic acids, terpenoids, steroids, and organic acids, and exhibit anti-inflammatory, antioxidant, anti-tumor, antiviral, immunomodulatory, anti-hepatic injury, and antibacterial effects (Ji et al., 2020; Zhu et al., 2020; Hu et al., 2021). Among these compounds, polysaccharides and flavonoids are considered representative active constituents of T. hemsleyanum and have shown potential application prospects in the development of food, medicine, and cosmetics (Shi et al., 2022; Wang et al., 2025).

With the increasing recognition of its medicinal value and the continuous growth of market demand, the utilization of T. hemsleyanum has gradually expanded in Chinese medicinal material processing, health product development, and the construction of local specialty medicinal herb industries. Its artificial cultivation area has also increased accordingly. However, the development of the T. hemsleyanum industry is still in a transitional stage from wild harvesting to standardized artificial cultivation, and shortcomings remain in seedling propagation, cultivation cycles, yield stability, quality control, processing and storage, and industrial chain construction (Hu et al., 2023; Pang et al., 2024). For a long time, T. hemsleyanum resources have mainly depended on wild harvesting. Due to its long natural growth cycle, slow tuberous root formation, overharvesting, and habitat destruction, wild resources have declined significantly, and in some major producing areas it has been regarded as a rare, endangered, or even nearly extinct medicinal plant resource (Ji et al., 2020; Zhu et al., 2020; Shi et al., 2022). Therefore, artificial cultivation has become an inevitable choice for alleviating the contradiction between resource supply and demand, protecting wild populations, and promoting sustainable industrial development.

T. hemsleyanum is naturally distributed in shaded and humid habitats such as gullies, valley slopes, and forest margins. It prefers shaded and humid conditions, is sensitive to strong light, and grows well in humus-rich, loose, and well-drained soils. Its growth and secondary metabolite accumulation are highly sensitive to environmental factors such as light, temperature, and moisture (Shi et al., 2022; Wang et al., 2025). Understory cultivation of medicinal plants is a new ecological cultivation model based on the principle of forest-medicine symbiosis, which makes use of forest canopy, light, temperature, moisture, and soil conditions for medicinal plant production (Li et al., 2025). Existing studies have shown that factors in the understory environment, such as light intensity, air temperature and humidity, soil fertility, pH, and microbial communities, can affect the yield and quality of medicinal plants by influencing photosynthesis, respiration, and secondary metabolism. Meanwhile, understory cultivation also contributes to forest resource conservation, biodiversity maintenance, ecological environment improvement, and sustainable forestry development, and has become an important direction for the forest medicinal herb industry (Guo et al., 2026).

This study explores the construction pathway of an understory ecological cultivation model for T. hemsleyanum. Existing studies have mainly focused on its pharmacological activity, chemical composition, quality control, and greenhouse or field cultivation, whereas systematic research on its understory ecological cultivation model remains relatively insufficient. Considering that relatively mature technical frameworks have gradually been established for the understory cultivation of other medicinal plants, including the optimization of shading intensity, canopy structure regulation, soil management, economic benefit evaluation, and ecological function analysis, it is necessary to systematically examine the understory ecological cultivation of T. hemsleyanum in relation to its biological characteristics and ecological adaptability. Therefore, this study analyzes the resource value, understory habitat adaptability, ecological cultivation model construction, key cultivation techniques, and industrial development needs of T. hemsleyanum, with the aim of providing theoretical references and practical support for suitable stand selection, cultivation technology optimization, and standardized production of this species.

2 Biological Characteristics and Growth Requirements of Tetrastigma hemsleyanum

2.1 Morphological characteristics and growth habits of Tetrastigma hemsleyanum

Tetrastigma hemsleyanum is a perennial herbaceous climbing vine of the genus Tetrastigma in the family Vitaceae, with distinct climbing characteristics. Its stems are slender and flexible, with longitudinal ridges, and adventitious roots may develop from the lower nodes. Young stems are mostly green and cylindrical, while older stems gradually become flattened and purplish brown, usually glabrous or sparsely pubescent (Zhu et al., 2020). The leaves of T. hemsleyanum are mostly palmately compound, usually composed of three leaflets and arranged alternately along the stem. The leaflets are generally lanceolate to ovate-lanceolate, with serrated margins, acuminate tips, and cuneate or nearly rounded bases. The leaves are dark green and can adapt well to the diffuse light environment under forest canopies (Guo et al., 2019). Its flowers are small and yellow-green, often borne in axillary umbels. The flowering period generally lasts from April to June, and the fruiting period from August to November. The berries turn bright red when mature and may remain on the plant for a relatively long time (Ji et al., 2020).

The underground part of T. hemsleyanum forms typical tuberous roots, which may be calabash-shaped, spindle-shaped, or ovoid. These tuberous roots usually occur singly or as several bead-like connected segments. The epidermis is mostly yellowish brown and relatively smooth, although wrinkles, lenticel-like protrusions, or depressions with residual roots may also be observed (Guo et al., 2019; Ji et al., 2020). The tuberous root is the main medicinal part of T. hemsleyanum and is also an important indicator for evaluating yield, commercial value, and medicinal quality in artificial cultivation. Anatomical studies have shown obvious differences among fibrous roots, bar-shaped roots, and calabash-shaped roots in vascular bundle integrity and intracellular inclusion accumulation, reflecting the gradual transformation of the underground part from a nutrient-absorbing organ into a medicinal storage organ (Xiang et al., 2021).

In terms of growth habits, T. hemsleyanum is naturally distributed mostly in shaded and humid environments, such as forest understories on mountain slopes, valley margins, shrublands, and rock crevices. It exhibits ecological characteristics of preferring shade and moisture, tolerating low light, and being sensitive to strong sunlight exposure (Guo et al., 2019). As a climbing plant, T. hemsleyanum mainly relies on tendrils opposite the leaves to twine around surrounding vegetation, supports, or rock walls and grow upward. This characteristic determines its spatial ecological niche in warm-temperate evergreen forests and subtropical understory shrublands (Guo et al., 2019). There is a certain coordination between aboveground vine growth and underground tuberous root enlargement: the early stage is dominated by stem and leaf expansion and vegetative growth, while the later stage gradually shifts toward underground tuberous root accumulation. Therefore, in understory ecological cultivation, the perennial habit, vine-like growth, climbing ability, and medicinal use of the tuberous roots of T. hemsleyanum should be comprehensively considered, and suitable support structures, moderate light, and a stable rhizosphere environment should be provided.

2.2 Requirements of Tetrastigma hemsleyanum for light, temperature, and humidity

T. hemsleyanum shows strong selectivity for ecological environments, especially in terms of light, temperature, and humidity. In its natural distribution, it is commonly found at elevations of approximately 300~1 300 m in humid grassland patches, mountain slopes, valleys, stream banks, and rock crevices with diffuse light, and it is suitable for growth in cool, humid, humus-rich soils (Guo et al., 2019). Its suitable soils are mostly yellow or yellow-brown acidic soils, with a pH of approximately 4.3~7.7. Meanwhile, T. hemsleyanum is highly sensitive to strong light and drought; excessive radiation and water deficit may lead to leaf water loss, reduced photosynthetic efficiency, and inhibited plant growth (Ji et al., 2020). Ecological niche modeling further indicates that the potential suitable habitats of T. hemsleyanum are constrained by climatic factors such as mean diurnal temperature range and precipitation during the warmest quarter. Under future climate warming scenarios, its highly suitable distribution areas may shrink significantly, suggesting that this species has a relatively narrow climatic niche.

T. hemsleyanum has strong low-light adaptability and is suitable for growth in semi-shaded or diffuse-light environments. Physiological and cultivation studies have shown that approximately 67% shading is more favorable for the growth of T. hemsleyanum, whereas excessive light suppresses its physiological activity and plant development (Zhu et al., 2020). Excessive direct sunlight can easily cause leaf scorching, enhanced transpiration, and decreased photosynthetic efficiency, while excessive shading may also lead to vine overgrowth, thin leaves, and insufficient accumulation of photosynthetic products, which is unfavorable for tuberous root enlargement. Therefore, the key to understory ecological cultivation is not simply to increase shading, but to create an understory microclimate with moderate shading, sufficient diffuse light, and good ventilation. Light quality and other environmental factors can also regulate biomass and active compound accumulation in T. hemsleyanum. Continuous low-intensity blue light treatment can increase tuberous root yield, photosynthetic efficiency after light saturation, flavonoid content, and antioxidant activity, indicating that moderate light stress may promote both plant growth and medicinal quality formation (Zhao et al., 2024). Therefore, in constructing understory ecological cultivation models, attention should be paid to the influence of canopy-filtered light environments on the quality formation of T. hemsleyanum.

Temperature and humidity are also important ecological factors affecting the growth and development of T. hemsleyanum. This species is suitable for growth in warm and humid environments, with an optimal growth temperature of approximately 25°C. When winter temperature drops to about 10°C, plant growth tends to stagnate, indicating that although it is adapted to warm-temperate evergreen forest environments, it remains sensitive to low temperatures (Guo et al., 2019; Zhu et al., 2020). Higher air humidity helps maintain leaf physiological activity and vine growth, while moderate soil moisture facilitates root absorption of water and nutrients. However, T. hemsleyanum prefers humid conditions but does not tolerate long-term waterlogging. If drainage is poor under forest canopies and the soil remains waterlogged for a long period, root hypoxia may occur, increasing the risk of soil-borne diseases such as root rot. Therefore, understory ecological cultivation should make full use of the forest canopy to buffer high temperature, strong light, and water evaporation, while maintaining a rhizosphere environment that is “moist but not waterlogged” through drainage ditches, slope planting, and organic mulching.

2.3 Characteristics of tuberous root formation and medicinal part accumulation in Tetrastigma hemsleyanum

The tuberous root of T. hemsleyanum is its main medicinal organ and the most economically valuable part in artificial cultivation. Tuberous root formation is not completed at once, but undergoes a continuous developmental process from fibrous roots to bar-shaped roots and then to calabash-shaped tuberous roots (Guo et al., 2019; Ji et al., 2020). Anatomical studies have shown that fibrous roots retain relatively intact vascular bundle structures and contain fewer intracellular inclusions. In the bar-shaped root stage, partial vascular bundle degeneration occurs, accompanied by the initial accumulation of inclusions. Mature calabash-shaped tuberous roots retain only traces of vascular bundles but contain abundant intracellular inclusions, which are considered important storage forms of medicinal substances (Xiang et al., 2021). Therefore, the enlargement of tuberous roots in T. hemsleyanum is essentially the result of root morphogenesis, vascular tissue changes, and storage substance accumulation.

Tuberous root formation is closely related to vegetative growth, photosynthate transport, and underground nutrient accumulation. In the early growth stage, T. hemsleyanum mainly enhances photosynthesis through the expansion of aboveground stems and leaves, providing a material basis for subsequent underground growth. As the plant enters a relatively stable growth stage, part of the nutrients is gradually transported to the underground organs, promoting tuberous root enlargement and dry matter accumulation. Transcriptome studies have found that tuberous root enlargement in T. hemsleyanum is associated with changes in the expression of genes related to cell wall modification, hormone signaling, and membrane components, indicating that root thickening and storage substance accumulation are regulated by complex regulatory networks (Xiang et al., 2021). Because T. hemsleyanum grows slowly and requires multiple years to form fully developed tuberous roots, its cultivation cycle is relatively long. Premature harvesting should therefore be avoided in production, as it may affect medicinal material yield and quality (Zhu et al., 2020; Hu et al., 2021).

In terms of medicinal part accumulation, active constituents in T. hemsleyanum show obvious tissue specificity. Studies have shown that the tuberous roots are rich in flavonoids, phenolic acids, terpenoids, polysaccharides, and other metabolites. Key indicator compounds such as polydatin, piceatannol, resveratrol, and kaempferol can be stably detected and are often used for medicinal material quality evaluation (Hu et al., 2021; Hu et al., 2023). Integrated metabolomic and transcriptomic studies further show that flavonoids, glycosides, alkaloids, and terpenoids are highly accumulated in tuberous roots, while leaves and fibrous roots are rich in certain flavonols and organic acids, indicating functional differentiation among different tissues in medicinal compound accumulation (Luo et al., 2022; Peng et al., 2025). Spatial metabolomics has also confirmed that some flavonoids, such as vitexin-2″-O-glucoside, are concentrated in the epidermis and xylem of tuberous roots, further supporting the status of tuberous roots as the core medicinal part (Fu et al., 2019; Chen et al., 2024). Therefore, understory ecological cultivation of T. hemsleyanum should establish a balance among light regulation, soil improvement, water and fertilizer management, and harvesting age, so as to promote stable tuberous root formation and active compound accumulation.

3 Analysis of the Understory Habitat Adaptability of Tetrastigma hemsleyanum

3.1 Adaptability of Tetrastigma hemsleyanum to low-light understory environments

Tetrastigma hemsleyanum is naturally distributed mostly in mountain forest margins, valley shrublands, and shaded, humid understory environments, showing strong adaptability to low-light conditions. Compared with open areas exposed to strong light, understory environments can effectively reduce direct solar radiation and create light conditions dominated by diffuse and filtered light, which is highly consistent with the ecological characteristics of T. hemsleyanum, namely its preference for shade and moisture and sensitivity to strong sunlight. Light-gradient experiments showed that under full light and 30%, 50%, 70%, and 90% shading treatments, the contents of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in T. hemsleyanum increased with increasing shading intensity. Most photosynthetic parameters, including net photosynthetic rate, stomatal conductance, transpiration rate, apparent quantum efficiency, and maximum net photosynthetic rate, reached their highest values under approximately 70% shading and then decreased under stronger shading conditions (Xu et al., 2018). This indicates that moderate shading helps T. hemsleyanum maintain relatively high photosynthetic activity, whereas excessive light or excessive shading is unfavorable for plant growth.

A low-light understory environment does not mean that less light is always better. Although T. hemsleyanum has a certain degree of shade tolerance, its stem and leaf growth, photosynthesis, and tuberous root enlargement still require an appropriate amount of light energy. Earlier studies using 10%, 15%, and 30% of full sunlight showed that under moderate low-light conditions, namely 15% of full sunlight, T. hemsleyanum had higher photosynthetic capacity and yield, further indicating that it is adapted to diffuse and moderately weak light under forest canopies rather than full light or extremely dark environments. If stand canopy closure is too high and understory light transmittance is insufficient, plants are prone to vine overgrowth, thin leaves, and elongated internodes, leading to reduced accumulation of photosynthetic products and ultimately affecting underground tuberous root formation. Therefore, understory cultivation of T. hemsleyanum should emphasize “moderate shading” rather than “complete shading”. Stable and sufficient diffuse light should be provided by regulating canopy density, pruning branches and leaves, and arranging planting spacing properly.

From the perspective of ecological adaptation, low-light understory environments can provide T. hemsleyanum with light conditions close to its natural habitat, helping reduce environmental stress in artificial cultivation. Especially during periods of high temperature and strong light in summer, canopy shading can reduce leaf water loss and the risk of photoinhibition, thereby improving plant survival and growth continuity. Further studies have shown that T. hemsleyanum also has strong plasticity in response to changes in light quality. Continuous low-intensity blue light supplementation can significantly increase tuberous root yield, flavonoid content, and antioxidant activity, and enhance photosynthetic efficiency after light saturation, indicating that T. hemsleyanum can efficiently utilize limited light by optimizing photochemical processes and antioxidant systems (Zhao et al., 2024). In greenhouse photovoltaic systems, exogenous nitric oxide and phytohormones such as salicylic acid and jasmonic acid can restore photosynthetic parameters, reduce reactive oxygen species accumulation, and enhance plant adaptability to low-light and heterogeneous light environments (Figure 1) (Xie et al., 2022). Therefore, the rational use and regulation of understory light environments constitute an important basis for constructing ecological cultivation models for T. hemsleyanum and are also key to coordinating medicinal material yield and quality improvement.

3.2 Adaptability of Tetrastigma hemsleyanum to understory soil and moisture conditions

T. hemsleyanum has certain requirements for soil conditions and is suitable for growth in deep, loose, humus-rich, and well-drained soils. Understory soils usually have relatively high organic matter content due to long-term litter return, and their relatively favorable aggregate structure can provide a suitable rhizosphere environment for root extension and tuberous root enlargement. Understory environments are also characterized by strong soil structural heterogeneity, variable moisture conditions, and distinctive microbial communities, all of which jointly affect root development, nutrient absorption, and medicinal component accumulation in T. hemsleyanum. Studies have shown that intercropping T. hemsleyanum under moso bamboo forests and applying biochar-based organic fertilizer can significantly increase plant biomass, improve soil pH and soil organic carbon content, and alter bacterial community structure, indicating that improvements in soil physicochemical properties and microbial communities can jointly promote the growth of T. hemsleyanum (Zhang et al., 2019a).

However, understory soil environments also show variability and limiting factors. In some forestlands, well-developed tree roots may compete with T. hemsleyanum for water and nutrients; in low-lying or poorly drained plots, waterlogging may occur during the rainy season, resulting in root hypoxia and tuberous root decay. If understory land lacks long-term management, soil compaction, acidification, or pathogen accumulation may also occur. Therefore, understory cultivation of T. hemsleyanum should not rely solely on natural forestland conditions. Instead, soil fertility, permeability, pH, drainage status, and the rhizosphere microbial environment should be comprehensively assessed before planting. Pot experiments showed that pyrolytic organic matter, namely biochar, and organic fertilizer can both increase fresh root weight in T. hemsleyanum, with biochar being particularly effective in increasing plant height and total flavonoid content. These effects are associated with increases in soil available nitrogen, available phosphorus, available potassium, organic matter content, and enhanced activities of soil enzymes such as urease, protease, and cellobiohydrolase (Jiang et al., 2023). Therefore, in understory ecological cultivation, soil conditions can be optimized through the application of well-decomposed organic fertilizer, biochar-based fertilizer, drainage ditch construction, and mulching improvement.

Moisture conditions are an important factor affecting the growth of T. hemsleyanum. This species prefers humid conditions but does not tolerate long-term waterlogging, and it is suitable for growth in environments with relatively high air humidity, moderate soil moisture, and good drainage. Due to shading and litter coverage, understory environments can usually maintain relatively high humidity and reduce drought stress. However, during the plum rain season or periods of heavy rainfall, an inadequate drainage system may also induce root diseases. Soil microbial communities and rhizosphere conditions in different habitats also play an important role in the quality formation of T. hemsleyanum. Stony soils commonly found in mountainous forest terrain can support distinctive bacterial communities and enrich specific groups such as Actinobacteria and Rhizobiales. After two consecutive years of growth in such soils, T. hemsleyanum can form larger tuberous roots, and correlation analyses suggest that these microorganisms may promote tuberous root growth by releasing nutrients from rocks and regulating pathways related to phytohormone biosynthesis and stress resistance. Comparative studies of wild and cultivated populations have also shown that higher available phosphorus and potassium levels and distinctive rhizosphere microbial structures in wild habitats are associated with higher total flavonoid content and phenylalanine ammonia-lyase activity in roots. In addition, an appropriate amount of nitrogen is beneficial to the growth of T. hemsleyanum, whereas excessive nitrogen suppresses growth and reduces flavonoid and phenolic contents, indicating that high-quality understory production requires balanced nutrient supply rather than simply increasing fertilizer input (Fu et al., 2019). Therefore, understory ecological cultivation of T. hemsleyanum should follow the principles of “moisture retention without waterlogging” and “balanced fertilization” to create a stable rhizosphere environment for tuberous root formation and medicinal substance accumulation.

3.3 Growth performance of Tetrastigma hemsleyanum in different forest stand environments

Different forest stand environments vary markedly in shading degree, soil fertility, root competition, ventilation conditions, and management convenience, thereby affecting the growth performance of T. hemsleyanum. Field and controlled-environment studies have shown that intercropping T. hemsleyanum under moso bamboo stands combined with the application of biochar-based organic fertilizer can significantly increase plant biomass, indicating that T. hemsleyanum can grow well under relatively dense bamboo canopies when soil conditions are improved (Zhang et al., 2019a). Bamboo understories are characterized by relatively high humidity and stable shading, making them suitable for vine growth in T. hemsleyanum. However, dense bamboo rhizomes may compete with T. hemsleyanum for nutrients and space, and poor ventilation in some bamboo forests may increase disease risk. Therefore, when cultivating T. hemsleyanum under bamboo forests, bamboo culms should be appropriately thinned to improve light transmission and ventilation, while soil fertility supplementation and water drainage should be strengthened.

Cultivating T. hemsleyanum under fruit forests offers good advantages in spatial utilization. Fruit tree spacing is relatively regular, which facilitates land preparation, trellising, fertilization, and harvesting management. Understory light can also be regulated through canopy pruning, making this model suitable for the development of forest-medicine compound management. Although systematic trials on fruit forest-T. hemsleyanum cultivation remain relatively limited, fruit forests can be regarded as an important potential type for understory ecological cultivation of T. hemsleyanum based on its requirements for moderate shading, humid conditions, and vertical space utilization. However, fertilization, pesticide application, and irrigation measures in fruit tree management may affect the growth and medicinal material safety of T. hemsleyanum. Therefore, water and fertilizer management as well as pest and disease control for fruit trees and T. hemsleyanum should be coordinated to avoid interference between management practices.

Broad-leaved forests or near-natural stands are closer to the wild habitats of T. hemsleyanum, with advantages such as abundant litter, higher soil humus content, and stronger ecological stability, making them suitable for the development of simulated wild ecological cultivation models. In mixed broad-leaved forests with approximately 70% canopy density, soils containing a relatively high proportion of gravel can support the formation of larger tuberous roots and distinctive microbial communities in T. hemsleyanum, indicating that broad-leaved forest stands with moderate canopy closure, stony soils, and stable microclimates can provide a suitable ecological niche for cultivation. Seasonal climate analysis showed that moderate temperatures of 17.5°C~24.1°C, humidity of approximately 67%~80%, relatively low precipitation, and shorter sunshine duration are conducive to the formation of higher total flavonoid content in tuberous roots (Shi et al., 2022). Overall, different forest stands can provide certain conditions for understory cultivation of T. hemsleyanum, but suitable models should be selected according to stand structure, canopy closure, soil conditions, and management objectives. At the same time, regulation experience from greenhouse and stereoscopic planting systems can be used as a reference to further optimize understory ecological cultivation schemes (Xie et al., 2022; Hu et al., 2023).

4 Construction of Understory Ecological Cultivation Models for Tetrastigma hemsleyanum

4.1 Tetrastigma hemsleyanum-bamboo forest compound cultivation model

The Tetrastigma hemsleyanum-bamboo forest compound cultivation model is a forest-medicine compound model that uses the relatively stable shaded environment and humid microclimate under bamboo forests to cultivate T. hemsleyanum ecologically within bamboo forest spaces. Moso bamboo (Phyllostachys edulis) forests usually have relatively high canopy closure and a stable microclimate, forming a cool, humid, and shaded understory environment. This is highly consistent with the ecological requirements of T. hemsleyanum, which prefers warm-temperate evergreen forest habitats and moderately low-light conditions. Light-treatment studies have shown that approximately 70% shading is beneficial to photosynthesis and growth in T. hemsleyanum. Therefore, when constructing a compound cultivation model under bamboo forests, canopy shading regulation should be regarded as one of the key technical links (Xu et al., 2018). Bamboo forest floors usually contain abundant litter, which can increase soil organic matter content and improve soil structure after decomposition, thereby providing a certain basis for root development and tuberous root enlargement in T. hemsleyanum. However, long-established bamboo forest soils are usually acidic, and nutrient supply and pH regulation should be strengthened after intensive understory cultivation is introduced (Zhang et al., 2019a).

In constructing this model, planting areas should be reasonably determined according to bamboo forest canopy closure, bamboo stand density, rhizome distribution, and topographic conditions. T. hemsleyanum can be intercropped between bamboo rows, using bamboo culms, simple mesh frames, or understory support structures to support its climbing growth, so that the vines are distributed upward in an orderly manner and poor ventilation and disease occurrence caused by long-term creeping along the ground can be avoided. In plots with overly dense bamboo stands and insufficient understory light, weak, old, and overly dense bamboo culms should be thinned appropriately to improve understory ventilation and light transmission. In areas with dense bamboo rhizomes and strong root competition, ditch isolation, localized land preparation, and the application of well-decomposed organic fertilizer and biochar-based organic fertilizer can be used to reduce water and nutrient competition between bamboo rhizomes and T. hemsleyanum. Studies have shown that, compared with pure moso bamboo forests, moso bamboo-T. hemsleyanum systems can increase soil organic carbon and available nitrogen contents, but soil pH and available potassium contents are lower. This suggests that potassium supplementation should be emphasized in production, and alkaline amendments should be applied when necessary (Zhang et al., 2019b).

The advantages of the T. hemsleyanum-bamboo forest compound cultivation model lie in its stable ecological environment, suitable shading conditions, and relatively high utilization efficiency of forestland space, making it suitable for promotion in mountainous areas rich in bamboo resources. Related studies have shown that applying biochar-based organic fertilizer under moso bamboo forests can increase soil pH and organic carbon content, significantly increase T. hemsleyanum biomass, and reshape bacterial community structure at the phylum and genus levels. At the same time, bamboo forest-medicinal plant systems can increase soil bacterial diversity and alter dominant bacterial groups, with soil pH, organic carbon, and available phosphorus being closely related to microbial community structure (Zhang et al., 2019c). Therefore, this model should comprehensively integrate reasonable plant and row spacing, organic fertilizer or biochar-based fertilizer application, potassium supplementation, pH regulation, drainage management, and green pest and disease control measures, so as to maintain habitat conditions characterized by “moderate shading, good ventilation, loose soil, and moisture without waterlogging” and improve the survival rate, tuberous root yield, and medicinal material quality of T. hemsleyanum.

4.2 Tetrastigma hemsleyanum-fruit forest compound cultivation model

The Tetrastigma hemsleyanum-fruit forest compound cultivation model refers to planting T. hemsleyanum between fruit tree rows or in the lower spaces beneath fruit tree canopies, thereby realizing compound management of fruit trees and medicinal plants. Fruit forests can provide certain shading, diverse litter inputs, and a relatively stable understory microclimate for T. hemsleyanum. At the same time, fruit tree spacing is usually relatively regular, and the understory space is relatively open, facilitating land preparation, trellising, fertilization, irrigation, and harvesting management. Compared with bamboo forests, fruit forest understories have stronger management controllability. They can reduce the adverse effects of strong summer light and high temperature on T. hemsleyanum while improving land-use efficiency and comprehensive output per unit area by utilizing the lower spaces under fruit trees.

Although specialized studies on fruit tree-T. hemsleyanum compound systems remain relatively limited, fruit tree-herb intercropping and other orchard agroforestry models can provide important references. In karst rocky desertification control areas, intercropping fruit trees with herbaceous legumes significantly improved economic returns compared with monoculture orchards and enhanced ecosystem services such as groundwater recharge, soil and water conservation, and carbon sequestration. This indicates that a “fruit tree + understory herb” structure can coordinate ecological protection and economic benefits (Cheng et al., 2022). Global studies on horticultural intercropping and fruit tree agroforestry also show that well-designed tree-crop combinations can improve land-use efficiency, yield stability, and the ability to resist climate stress (Burgess et al., 2022; Paut et al., 2024). Therefore, from the perspective of agroforestry management principles, cultivating T. hemsleyanum under fruit forests has a sound theoretical basis and promotion potential.

In model design, fruit forests with open crowns, moderate canopy closure, and stable management intensity, such as citrus, bayberry, and loquat orchards, should be prioritized. For shade-loving and climbing medicinal plants such as T. hemsleyanum, fruit tree species and planting densities should be reasonably selected so that the understory environment approaches the moderate light and humidity conditions favorable for flavonoid accumulation, such as temperatures of approximately 17.5°C~24.1°C, air humidity of approximately 67%~80%, and shorter sunshine duration (Shi et al., 2022). During planting, areas where fruit tree main roots are concentrated should be avoided, T. hemsleyanum planting belts should be reasonably arranged, and supports or mesh frames should be configured to guide vines to climb in an orderly manner, thereby reducing spatial, water, and nutrient competition with fruit trees. Existing studies have shown that, compared with simple creeping cultivation, stereoscopic cultivation can increase tuberous root yield and enhance the contents of key quality markers such as polydatin, piceatannol, resveratrol, and kaempferol in T. hemsleyanum (Hu et al., 2023). Therefore, in fruit forest understory cultivation of T. hemsleyanum, fertilization, pruning, pest and disease control, and harvesting arrangements for fruit trees and medicinal plants should be coordinated. Organic fertilizers, green control measures, and low-residue management practices should be adopted as much as possible to form a fruit-medicine compound cultivation system that is coordinated and non-interfering.

4.3 Tetrastigma hemsleyanum-broad-leaved forest simulated wild cultivation model

The Tetrastigma hemsleyanum-broad-leaved forest simulated wild cultivation model is a low-intervention and ecological cultivation model carried out under natural or semi-natural warm-temperate evergreen broad-leaved forests, subtropical broad-leaved forests, or near-natural mixed forests, with the core aim of simulating the natural habitat of T. hemsleyanum. The native habitats of T. hemsleyanum are mostly humid shrublands, valleys, and mountain slopes at elevations of 300~1 300 m. Broad-leaved forest understories usually have abundant litter, relatively high air humidity, favorable soil humus content, and strong ecosystem stability, which can provide growth conditions relatively close to its wild state. Ecological niche modeling and phylogeographic analyses show that T. hemsleyanum is closely associated with warm-temperate evergreen forests, and its highly suitable habitats are controlled by climatic variables such as mean diurnal temperature range and precipitation during the warmest quarter. Under future climate warming scenarios, the highly suitable areas of T. hemsleyanum may shrink significantly, highlighting the importance of near-native habitat cultivation in existing suitable forest patches for protecting genetic resources and maintaining ecological functions (Wang et al., 2023).

In the specific construction process, broad-leaved forestlands with stable stand structures, moderate canopy closure, good drainage, deep soil layers, and relatively low human disturbance should be selected. Before planting, large-scale excavation and destructive land preparation should be avoided. Hole preparation, strip preparation, or localized soil improvement can be adopted to reduce disturbance to the forest ecosystem. T. hemsleyanum seedlings can be planted at low to moderate densities along forest margins, forest gaps, slopes, valley edges, or understory areas with better light transmission. Existing shrubs and trees can be used as natural supports, or simple supports and ecological mesh frames can be combined for vine guidance. Management should mainly rely on microhabitat selection, low-disturbance land preparation, litter retention, and limited inputs, so as to maintain local soil microbial communities, litter cycling, and water regulation mechanisms, while highlighting ecological cultivation and simulated wild-quality characteristics.

Seasonal field studies have shown that under cool, humid spring conditions with shorter sunshine duration, the total flavonoid content and antioxidant activity of T. hemsleyanum tuberous roots are relatively high, and its flavonoid biosynthesis pathway is closely coupled with environmental factors throughout the annual cycle (Figure 2) (Shi et al., 2022). Light-intensity experiments further demonstrate that excessive radiation and high temperature reduce photosynthetic activity in T. hemsleyanum, whereas approximately 70% shading can optimize pigment content and photosynthesis (Xu et al., 2018). Therefore, in the broad-leaved forest simulated wild model, understory locations with moderate canopy shading, stable microclimates, and moist but non-waterlogged soils should be prioritized, so that the ecological conditions can approximate those required for the natural growth of T. hemsleyanum. The outstanding advantage of this model is that the ecological environment is close to nature and the medicinal material has a favorable quality image, making it suitable for the development of ecological medicinal materials, geo-authentic medicinal materials, and branded products. However, its management and harvesting are relatively difficult, and yield stability may be lower than that of intensive cultivation models. Therefore, in promotion and application, the model should be positioned according to production objectives. If ecological quality and resource conservation are prioritized, a low-density and low-intervention simulated wild model can be adopted. If stable yield and large-scale management are the goals, cultivation management should be moderately strengthened on the basis of simulated wild cultivation to balance ecological value and productivity.

5 Key Cultivation Techniques for Understory Planting of Tetrastigma hemsleyanum

5.1 Propagation and planting of high-quality Tetrastigma hemsleyanum seedlings

The foundation of understory ecological cultivation of Tetrastigma hemsleyanum lies in obtaining high-quality seedlings and carrying out standardized planting. Seedling quality directly affects plant survival rate, later growth vigor, tuberous root formation, and the stability of medicinal material quality. Therefore, seedlings with clear provenance, stable traits, no pests or diseases, complete root systems, and vigorous growth should be selected as cultivation materials. Traditional seed propagation and cutting propagation are limited by low natural fruiting rate and restricted propagation quantity, making it difficult to fully meet the demand for large-scale understory cultivation. As a result, rapid propagation technologies have attracted increasing attention (Hu et al., 2021). In production, tuberous root propagation, cutting propagation, and tissue culture can be used for seedling propagation, among which tissue culture is conducive to the rapid propagation of seedlings with uniform morphology, genetic stability, and a high degree of disease-free quality (Pang et al., 2024).

Tissue culture is an important direction for the large-scale propagation of high-quality T. hemsleyanum seedlings. Tissue culture techniques based on axillary bud proliferation or shoot organogenesis can produce a large number of tissue-cultured seedlings with stable morphology, relatively stable flavonoid content, and high uniformity, thereby meeting both resource conservation needs and commercial production requirements. Studies have shown that when leaves and petioles are used as explants and induced on Murashige and Skoog (MS) medium supplemented with appropriate combinations of 6-benzylaminopurine and auxins, a relatively high adventitious shoot proliferation rate can be obtained within 30 days. Optimized rooting media can achieve a 100% rooting rate, and the survival rate of tissue-cultured seedlings after acclimatization in a peat-sand substrate can exceed 98% (Pang et al., 2024).

For large-scale seedling production suitable for understory transplantation, cutting propagation remains a practical and relatively low-cost method. Cutting propagation experiments have shown that when 2- to 3-year-old cuttings are treated with 1 000 mg/L indole-3-butyric acid for 10 s and then planted in loess, rooting performance is relatively good, providing a technical basis for standardized production of robust seedlings. Both tissue-cultured seedlings and cutting-derived seedlings should be fully hardened before transplantation into understory environments, so that they can gradually adapt to understory temperature, humidity, low-light, and ventilation conditions, thereby reducing transplanting stress and improving establishment speed (Zhang et al., 2019a; Hu et al., 2021). Before planting, localized land preparation or hole preparation should be carried out, and well-decomposed organic fertilizer should be applied as basal fertilizer. After planting, root-setting water should be applied promptly, and mulching or other moisture-retention measures should be adopted according to understory light and humidity conditions.

5.2 Vine guidance, trellising, and plant management of Tetrastigma hemsleyanum

T. hemsleyanum is a climbing vine with obvious twining and climbing growth characteristics in its aboveground parts. It requires support structures to make full use of vertical space, improve ventilation and light penetration, and reduce lodging. If allowed to creep naturally, plants are likely to become entangled with one another, causing excessive canopy closure within the crop layer, increasing disease risk, and hindering the transport of photosynthetic products to tuberous roots. Comparative studies of different planting models have shown that, compared with creeping cultivation, stereoscopic cultivation can significantly improve the quality of tuberous roots and increase the contents of compounds such as polydatin, piceatannol, resveratrol, and kaempferol. Greenhouse cultivation combined with stereoscopic planting can also produce higher aboveground and underground biomass, indicating that vertical support and spatial stratification are conducive to biomass accumulation and medicinal quality improvement (Hu et al., 2023).

Trellising management should follow the principle of not affecting normal tree growth or damaging the ecological structure of the forestland. Under bamboo forests and fruit forests, low supports, bamboo-pole supports, mesh frames, or simple hedge frames can be used to guide T. hemsleyanum vines upward or along the support surface, reducing ground contact and moisture accumulation. In simulated wild cultivation under broad-leaved forests, natural tree trunks, shrubs, or ecological supports can be appropriately used for climbing. Although systematic studies on dedicated understory trellising systems for T. hemsleyanum remain limited, experience from other medicinal climbing plants and vines can provide useful references. For example, trellised cultivation of Codonopsis javanica can increase plant height and leaf size compared with non-trellised treatment, showing certain practical application value (Son and Giang, 2026). Broader studies on climbing plants have shown that supports with small diameters and close spacing are important for climbers to form stable support networks (Figure 3) (Soffiatti et al., 2022; Yu et al., 2025).

Plant management also includes pinching, vine thinning, removal of diseased and weak branches and leaves, and regulation of vegetative growth. Vine guidance should be carried out in the early growth stage to prevent stems and vines from becoming too entangled to manage. For overly vigorous plants, vine overgrowth may be moderately controlled to promote nutrient allocation to underground tuberous roots. For plants with overly dense branches and leaves, weak branches, diseased branches, and excessive foliage should be removed in time to improve understory ventilation and reduce pest and disease risk. Reasonable vine management can help maintain coordination between aboveground growth and underground tuberous root development, making it an important technical measure for improving yield and quality in understory cultivation.

5.3 Water and fertilizer management and green pest and disease control of Tetrastigma hemsleyanum

Understory cultivation of T. hemsleyanum should follow the fertilization principle of using organic fertilizer as the main source and appropriate topdressing as a supplement. Understory environments are characterized by strong heterogeneity in soil nutrients and moisture. Although litter decomposition can provide a certain humus foundation, nutrient supplementation is still required during long-term cultivation to meet the needs of vine growth and tuberous root enlargement. Basal fertilizer should mainly consist of fully decomposed farmyard manure, compost, commercial organic fertilizer, or biochar-based organic fertilizer, combined with appropriate phosphorus and potassium fertilizers to improve root development and tuberous root fullness. Related studies have shown that when T. hemsleyanum is intercropped under moso bamboo forests, the application of biochar-based organic fertilizer can significantly increase plant biomass, improve soil pH and organic carbon content, and alter bacterial community composition (Zhang et al., 2019a).

Organic, slow-release, and ecological fertilization methods are more suitable for maintaining soil fertility and medicinal material quality in understory systems. Related studies have shown that biochar and organic fertilizer can increase root weight, plant height, total flavonoid content, and soil enzyme activity in T. hemsleyanum, indicating that improved soil fertility and enhanced rhizosphere activity help promote tuberous root formation and active compound accumulation. At the same time, excessive nitrogen input is associated with decreased flavonoid and phenolic contents, suggesting that the fertilization regime for T. hemsleyanum should be designed around medicinal material quality rather than simply pursuing maximum biomass or yield (Fu et al., 2019; Hu et al., 2021). Water management should follow the principle of “maintaining moisture while avoiding waterlogging”. Drainage should be strengthened during the rainy season, while drip irrigation, sprinkler irrigation, or organic mulching can be used for water supplementation and moisture retention during dry seasons.

In terms of pest and disease control, prevention should be prioritized, and a green control system combining agricultural, physical, biological, and low-risk chemical measures should be established. In high-humidity understory environments, T. hemsleyanum is prone to diseases such as root rot and leaf spot. Therefore, healthy seedlings, improved ventilation and light transmission, appropriate planting density, timely removal of diseased plant residues, and prevention of waterlogging should be used to reduce disease risk. For pests such as aphids and grubs, trapping, manual removal, biological agents, or low-toxicity and low-residue pesticides can be adopted. Studies have shown that endophytic fungi associated with the roots of T. hemsleyanum can promote root development and enhance plant vigor and stress resistance by secreting phytohormones and other substances. In the future, green understory management of T. hemsleyanum should integrate organic fertilizer and biochar-based fertilizer application, beneficial microbial utilization, rational density design, and low-residue control measures, so as to form an integrated ecological cultivation technology system that balances yield, medicinal material quality, and forest ecological environment protection (Li et al., 2025; Guo et al., 2026).

6 Effects of the Understory Environment on the Yield and Quality of Tetrastigma hemsleyanum

6.1 Effects of Light conditions on the plant growth of Tetrastigma hemsleyanum

Light is an important ecological factor affecting the understory growth of Tetrastigma hemsleyanum. Light intensity and light quality jointly determine plant morphogenesis, photosynthetic efficiency, and biomass allocation. T. hemsleyanum prefers shaded and humid conditions and is sensitive to strong light. In understory environments with diffuse light, it can better maintain leaf water status and physiological activity. Shading experiments have shown that, as shading intensity gradually increases from full light to 30%~90%, chlorophyll and carotenoid contents in T. hemsleyanum gradually increase, while most photosynthetic parameters, such as net photosynthetic rate, stomatal conductance, transpiration rate, and maximum net photosynthetic rate, reach their peaks at approximately 70% shading and then decline. This indicates that excessive light inhibits photosynthetic activity and normal growth in T. hemsleyanum (Xu et al., 2018). Under lower light conditions, namely 10%~30% of full sunlight, plants under 15% sunlight show higher photosynthetic capacity and yield than those under 10% and 30% sunlight, further indicating that T. hemsleyanum is better adapted to moderate diffuse light environments and is not suitable for strong direct light conditions.

However, the low-light adaptability of T. hemsleyanum does not mean that it can remain in excessively shaded environments for long periods. If stand canopy closure is too high and understory light transmission is insufficient, the plants may show rapid vine elongation, but this growth is often characterized by etiolation, including thinner leaves, elongated internodes, reduced tissue firmness, and insufficient accumulation of photosynthetic products, ultimately affecting underground tuberous root enlargement. Conversely, if understory shading is insufficient, strong light and high temperature may cause leaf scorching, wilting, and damage to the photosynthetic system, reducing plant survival. Therefore, understory cultivation should create a diffuse-light environment suitable for T. hemsleyanum growth by pruning tree canopies, adjusting planting locations, and controlling stand density, so that plants can avoid strong light stress while obtaining sufficient photosynthetically active radiation.

From the perspective of yield and quality formation, suitable light conditions can promote coordinated growth between the aboveground and underground parts of T. hemsleyanum. Healthy leaves are the basis for photosynthate formation, and only when the aboveground parts maintain moderate growth can sufficient nutrient sources be provided for tuberous root enlargement and medicinal substance accumulation. Light quality also significantly regulates growth and biomass allocation in T. hemsleyanum. Experiments using different colored films showed that blue film promoted plant height growth, leaf expansion, specific leaf weight, and fresh root weight, and increased soluble amino acid content and chalcone isomerase activity, thereby improving yield. Red film reduced root biomass but enhanced phenylalanine ammonia-lyase activity and total flavonoid content, indicating a certain trade-off between vegetative growth and secondary metabolism under different spectral conditions (Bai et al., 2021). In vitro regeneration studies also showed that when light intensity increased from 50 μmol·m⁻²·s⁻¹ to 200 μmol·m⁻²·s⁻¹, shoot proliferation and chlorophyll content increased, suggesting that young tissues can utilize higher light levels when other stress factors are controlled (Pang et al., 2024). Therefore, in the understory ecological cultivation of T. hemsleyanum, the light environment should be dynamically regulated according to stand type, seasonal changes, and plant growth stage, so that light conditions can protect plants from strong light stress while meeting their needs for photosynthesis and substance accumulation.

6.2 Effects of soil fertility on tuberous root yield of Tetrastigma hemsleyanum

The main medicinal part of T. hemsleyanum is the underground tuberous root, and soil fertility directly affects root development, tuberous root enlargement, and yield formation. Loose, fertile, and organic matter-rich soils can provide good extension space and nutrient supply for the roots of T. hemsleyanum, which helps enhance root absorption capacity and promote nutrient transport to underground parts. Because understory soils accumulate litter over long periods, they usually have a certain humus foundation, which can improve soil structure and enhance water and fertilizer retention to some extent, thereby creating a suitable rhizosphere environment for tuberous root formation. Pot experiments have shown that both low and high additions of pyrolytic organic matter, namely biochar, can significantly increase plant height and fresh root weight in T. hemsleyanum. Compared with the unfertilized control, fresh root weight and total flavonoid content increased by 1.60~2.70 times (Jiang et al., 2023).

Soil fertility is reflected not only in nutrient content but also in comprehensive conditions such as soil aeration, water retention, microbial activity, soil enzyme activity, and pH. The study by Jiang et al. (2023) showed that the yield- and quality-enhancing effects of biochar were associated with increases in soil available nitrogen, available phosphorus, available potassium, and organic matter levels, as well as enhanced activities of soil enzymes such as urease, protease, and cellobiohydrolase and increased chalcone isomerase activity. This indicates that improvements in soil fertility and microbial activity can jointly promote biomass accumulation and secondary metabolism in T. hemsleyanum. Application of organic fertilizer alone can also increase fresh root weight, but its promoting effect on total flavonoid content is relatively weaker, and its yield-increasing effect is mainly related to available potassium, available phosphorus, and protease activity (Jiang et al., 2023). Therefore, during understory cultivation, soil structure should be improved through the application of well-decomposed organic fertilizer, compost, biochar, and humus soil, and nutrients should be supplemented reasonably according to plant growth stages.

Field studies further emphasize the role of soil structure and microbial communities in tuberous root enlargement of T. hemsleyanum. After two consecutive years of cultivation in stony soils, T. hemsleyanum produced significantly larger tuberous roots than plants grown in similar soils from which stones had been removed. Stony soils had distinctive bacterial communities, higher microbial diversity, and enrichment of groups such as Actinobacteria and Rhizobiales. These differential bacteria were associated with host plant pathways related to phytohormone biosynthesis, photosynthesis, and stress resistance, indicating that microbial communities driven by stony soils can promote tuberous root initiation and enlargement in T. hemsleyanum (Hong et al., 2021). Comparative analysis of wild and cultivated rhizosphere environments also showed that higher available phosphorus and potassium contents and specific bacterial genera in wild soils were associated with increased total flavonoid content and phenylalanine ammonia-lyase activity in roots. Therefore, understory cultivation of T. hemsleyanum should establish a fertility management model based on organic fertilizer, balanced nitrogen, phosphorus, and potassium supply, and soil ecological health, so that soil conditions can truly support the simultaneous improvement of tuberous root yield and medicinal material quality.

6.3 Effects of cultivation years on the medicinal quality of Tetrastigma hemsleyanum

T. hemsleyanum is a perennial medicinal plant, and its tuberous root formation and accumulation of active substances follow an obvious temporal process. Generally, the shorter the cultivation period, the less sufficient the accumulation in the underground parts, resulting in smaller tuberous roots and underdeveloped dry matter content and medicinal quality. As the growth period extends, T. hemsleyanum continuously accumulates photosynthates and transports nutrients, leading to gradual enlargement of underground tuberous roots and improvements in the weight, fullness, and commercial value of the medicinal parts. Field observations have shown that larger tuberous roots of T. hemsleyanum usually begin to form in the later stage of the second growth year, and many cultivation systems also use tuberous roots of the same growth age for quality evaluation (Shi et al., 2022). Therefore, reasonably extending the cultivation cycle is one important way to improve the yield and quality of T. hemsleyanum medicinal materials.

However, a longer cultivation period is not always better. As cultivation time increases, problems such as nutrient depletion in understory soils, pathogen accumulation, root aging, and increased management costs may gradually emerge. If plants are continuously cultivated in the same plot for a long time without soil improvement or pest and disease control, plant vigor may decline, the rate of tuberous root decay may increase, and the stable supply of medicinal materials may be affected. Therefore, when determining the appropriate harvesting age for T. hemsleyanum, plant growth status, tuberous root size, medicinal material quality, market demand, and input-output ratio should be comprehensively considered, rather than using cultivation years as the sole criterion.

From the perspective of quality regulation, cultivation years and seasonal environments jointly affect the accumulation level and stability of medicinal components in T. hemsleyanum. A three-year trial with sampling every half month showed that the total flavonoid content and antioxidant activity in tuberous roots changed dynamically within a year and across different growth cycles, indicating that its secondary metabolism undergoes continuous adjustment. Seasonal analysis showed that under spring conditions with precipitation of 2.0~6.6 mm, temperature of 17.5°C~24.1°C, humidity of 67.3%~80.2%, and sunshine duration of 3.4~5.8 h, total flavonoid content in tuberous roots reached a relatively high level of 281.3~392.8 μg/g, suggesting that cool and moderately humid conditions are conducive to flavonoid enrichment (Shi et al., 2022). In addition, metabolomic and origin-tracing studies have identified catechin, darendoside B, resveratrol derivatives, and other compounds as key quality markers. These compounds differ among production areas and may be related to cultivation environments and cultivation history (Hu et al., 2023; Chu et al., 2024). Therefore, in production practice, age-specific management and timely harvesting systems should be established, and harvesting standards suitable for different understory cultivation models should be gradually developed based on production area conditions and quality testing results.

7 Benefit Analysis of Understory Ecological Cultivation of Tetrastigma hemsleyanum

7.1 Ecological benefits of understory cultivation of Tetrastigma hemsleyanum

Understory ecological cultivation of Tetrastigma hemsleyanum can make full use of forestland space and form a compound ecological structure integrating the tree layer, shrub-herb layer, and medicinal plant layer. Compared with monoculture open-field cultivation, understory cultivation is closer to the natural growth environment of T. hemsleyanum and can reduce the adverse effects of strong light, high temperature, and drought on plants, allowing T. hemsleyanum to grow in a relatively stable understory microclimate. Meanwhile, canopy shading, litter cover, and soil humus accumulation help maintain soil moisture, regulate surface temperature, and enhance the stability of forestland ecosystems. Existing studies have pointed out that understory vegetation plays an important role in forest ecosystem functioning by promoting ecosystem productivity, nutrient cycling, organic matter decomposition, and ecosystem self-renewal (Deng et al., 2023).

During understory cultivation, T. hemsleyanum causes relatively little disturbance to the original forestland structure. It does not require large-scale land clearing or intensive tillage, thereby helping reduce soil erosion and surface exposure. Especially in mountainous, hilly, and sloping forest areas, developing understory ecological cultivation of T. hemsleyanum can improve land-use efficiency while protecting forest vegetation and avoid ecological damage caused by blind land reclamation. Meta-analyses and review studies have shown that maintaining diverse understory plants helps preserve soil organic carbon, total nitrogen, soil water content, pH, and microbial biomass, whereas removing understory vegetation increases soil temperature and significantly reduces multiple soil properties (Zhang et al., 2022). In oil palm plantations, increasing understory cover, namely avoiding herbicide use, can improve the diversity and abundance of soil macrofauna and enhance litter decomposition rates, without obvious negative effects on soil fertility. This indicates that retaining and utilizing the understory vegetation layer has positive significance for maintaining soil ecological functions.

In addition, understory cultivation of T. hemsleyanum contributes to the conservation of medicinal plant resources. In the past, T. hemsleyanum resources depended largely on wild harvesting, and overharvesting could easily lead to the decline of wild populations and habitat degradation. Artificial understory ecological cultivation can reduce dependence on wild resources to a certain extent and promote a shift from “wild resource harvesting” to “conservation-oriented artificial cultivation”. Studies on mixed forests and agroforestry systems further show that diversified understory layers can improve ecosystem functions. A global meta-analysis of mixed plantations showed that, compared with monocultures, tree species mixing significantly increased understory plant biomass, cover, and species richness by approximately 30%~55%, while also improving soil nutrients, nutrient availability, microbial biomass, and carbon sequestration capacity (Guo et al., 2025). On the Loess Plateau, higher taxonomic and phylogenetic diversity of understory plants was positively correlated with ecosystem multifunctionality, especially in terms of nitrogen and phosphorus cycling, water conservation, and productivity enhancement (Sha et al., 2024). As a shade-tolerant medicinal vine with relatively deep roots, T. hemsleyanum can serve as a structural and functional understory component in bamboo forests, fruit forests, or broad-leaved forests, improving biodiversity and promoting soil processes while reducing herbicide use and the need for intensive surface disturbance.

7.2 Economic benefits of understory cultivation of Tetrastigma hemsleyanum

T. hemsleyanum has high medicinal development value and market utilization potential, and its tuberous roots, as the main medicinal part, have considerable economic value. T. hemsleyanum is widely regarded as a high-value medicinal plant with pharmacological activities such as anti-tumor, anti-inflammatory, antiviral, antipyretic, and immunomodulatory effects. In clinical and folk applications, it is also known as a “plant antibiotic” (Zhu et al., 2020; Pang et al., 2024). At present, more than 140~150 compounds have been identified from T. hemsleyanum, especially flavonoids and polysaccharides. Related studies support its development and utilization in areas associated with fever, pneumonia, hepatitis, liver injury, and other diseases (Ji et al., 2020; Hu et al., 2021). Relevant reviews suggest that T. hemsleyanum has high economic and social value and is an important rare resource with promising prospects for the development of new drugs, functional foods, and health products (Wang et al., 2025).

Planting T. hemsleyanum in the understory spaces of bamboo forests, fruit forests, or broad-leaved forests can increase medicinal material income without substantially affecting the management of existing forest trees or fruit trees, thereby improving the comprehensive output per unit forestland area. For mountainous areas and regions rich in forestland resources, understory cultivation of T. hemsleyanum can transform idle or inefficiently used understory space into a sustainable management resource and enhance the economic returns of forestland management. Resource investigations in Zhejiang Province show that wild populations of T. hemsleyanum are scarce and endangered, while the artificial planting area has expanded rapidly with increasing market demand, reaching approximately 104.55 hm², with an expected output of about 173.91 t. This indicates a clear commercial driving force for artificial cultivation. From the broader experience of medicinal plant production, although medicinal plants are often considered “minor crops” in terms of production scale, their trade value is relatively high. They can provide important income sources for rural households and offer opportunities for farmers to shift from low-value crop management to diversified production (Mofokeng et al., 2022).

From the perspective of production input and income stability, understory cultivation can make use of natural shading conditions and reduce the cost of constructing artificial shading facilities. Understory litter and humus resources can also improve soil fertility to some extent and reduce part of the cost of soil improvement. Although T. hemsleyanum has a relatively long cultivation cycle, once a stable cultivation system is established, standardized management can improve survival rate and tuberous root yield, thereby generating relatively sustained returns. A profitability analysis of high-value medicinal plants in smallholder systems in South Africa showed that such cultivation generated positive net farm income, with a return on investment of 0.77 per growing period, indicating that the cultivation of high-value medicinal plants has certain profitability potential (Mbelebele et al., 2024). However, the economic benefits of understory cultivation of T. hemsleyanum do not depend solely on yield; they are also affected by seedling costs, management level, harvesting age, market price, medicinal material grade, and sales channels. Therefore, economic stability and sustainable resource utilization in understory cultivation of T. hemsleyanum should be improved through high-quality seedlings, ecological cultivation, quality control, contract sales, and origin-based brand building (Zhu et al., 2020; Pang et al., 2024).

7.3 Industrial promotion value of understory cultivation of Tetrastigma hemsleyanum

Understory ecological cultivation of T. hemsleyanum has strong industrial promotion value and is especially suitable for demonstration and application in regions with forestland resources, humid climates, and a foundation in Chinese medicinal herb cultivation. This model can integrate forestry resources, medicinal plant resources, and local specialty industries, forming a forest-medicine compound management pathway and providing a new option for agricultural transformation and understory economic development in mountainous areas. The rapid progress of phytochemical and pharmacological research on T. hemsleyanum also provides important support for its industrial development potential. Comprehensive studies have shown that T. hemsleyanum has broad pharmacological activities, including anti-tumor, antioxidant, anti-inflammatory, antiviral, hepatoprotective, immunomodulatory, and analgesic effects, and is considered a potential high-quality source for the development of new drugs and health products (Ji et al., 2020; Zhu et al., 2020; Hu et al., 2021).

From the perspective of industrial chain extension, understory cultivation of T. hemsleyanum can not only provide raw medicinal materials but also drive the development of related sectors such as seedling propagation, primary processing at the production site, quality testing, brand packaging, and functional product development. T. hemsleyanum polysaccharides have antioxidant, anti-tumor, anti-inflammatory, immunomodulatory, and metabolic regulatory effects, showing clear application prospects in food, medicine, and cosmetics (Wang et al., 2025). New extraction and processing technologies, such as GA-BPNN-optimized flavonoid extraction and nanoparticle delivery systems, can significantly improve extraction efficiency, antioxidant capacity, anti-inflammatory activity, and bioavailability, helping promote the development of standardized preparations and functional foods. In addition, pectic polysaccharide fractions and freeze-dried products with enhanced hepatoprotective and immunomodulatory effects further expand the application space of T. hemsleyanum in high-end medicine and health products.

During promotion, attention should be paid to the construction of technical standards and quality control systems. The scarcity of wild resources and increasing market demand have promoted the expansion of artificial cultivation of T. hemsleyanum, but problems such as backward processing technology, storage difficulties, and imperfect detection methods still exist (Zhu et al., 2020). Reviews on medicinal plant commercialization point out that formalizing value chains, improving quality control, and strengthening the connection among cultivation, processing, and sales can promote rural economic development, create employment opportunities, and drive small and micro-enterprises in the transportation and processing chain (Mofokeng et al., 2022). Therefore, systematic technical protocols should be established in the future around high-quality seedling propagation, understory cultivation techniques, green pest and disease control, timely harvesting, primary processing at the production site, active compound detection, and quality traceability. Only by forming a positive linkage among ecological conservation, quality control, and market development can the understory ecological cultivation model of T. hemsleyanum achieve stable promotion and sustainable development (Ji et al., 2020; Hu et al., 2021; Wang et al., 2025).

8 Summary and Analysis

Understory ecological cultivation of Tetrastigma hemsleyanum is an important pathway for alleviating pressure on wild resources, improving the comprehensive utilization efficiency of forestland, and promoting the development of characteristic medicinal plant industries. With the rapid expansion of T. hemsleyanum cultivation, problems related to seedling quality control and provenance standardization have become increasingly prominent. Because T. hemsleyanum has a low natural fruiting rate, traditional cutting propagation produces a limited number of plants, while long-term tissue culture may induce somaclonal variation and affect genetic stability and flavonoid composition profiles. Therefore, establishing a stable and traceable seedling propagation system is particularly important. In the future, micropropagation, controlled subculture, slow-growth conservation, and stress-resistance-oriented strain selection should be integrated to screen, fix, and register superior strains, thereby constructing standardized seedling and provenance systems and providing cultivation materials with clear genetic backgrounds, stable quality, and strong adaptability for understory ecological cultivation.

From the perspective of production practice, understory cultivation of T. hemsleyanum still faces problems such as immature technical systems, insufficient standardization, and weak extension services. Light, temperature, humidity, soil fertility, pH, and microbial communities in understory environments are complex and variable. If canopy density, planting density, water and fertilizer management, and stand conditions are not properly matched, yield and quality fluctuations can easily occur. At present, there are still considerable differences among different cultivation bases and planting models in biomass and in the contents of key indicator compounds such as polydatin, piceatannol, resveratrol, and kaempferol. The fact that greenhouse plus stereoscopic cultivation outperforms some understory cultivation models in both yield and quality also indicates that a technical gap remains between understory ecological systems and intensive systems. Therefore, systematic technical protocols should be established for understory cultivation of T. hemsleyanum in terms of suitable stand selection, canopy density regulation, stereoscopic trellising, soil improvement, ecological fertilization, rhizosphere microbial regulation, and quality certification, so as to improve the reproducibility, stability, and promotion value of cultivation models.

Overall, the optimization of understory ecological cultivation of T. hemsleyanum should achieve coordinated integration of germplasm resources, field techniques, and industrial organization. At the technical level, experience from controlled-environment and greenhouse systems can be used as a reference to promote biomass accumulation and active compound formation through the regulation of light intensity and spectrum, temperature and humidity, nutrient supply, and moderate abiotic stress. Meanwhile, canopy-density zoning, stereoscopic trellising, the application of organic amendments such as biochar, and rhizosphere microbial management can be used to gradually construct an understory ecological cultivation environment close to a “semi-controlled” system. At the industrial level, a coordinated management mechanism between forestry and traditional Chinese medicine sectors should be established, the quality certification and regulatory system for understory-cultivated medicinal materials should be improved, and regional standardized demonstration bases should be developed to benchmark understory ecological cultivation against greenhouse and vertical farming models in terms of quality. Through the integration of contract farming, quality traceability, brand building, and processing and marketing systems, understory ecological cultivation of T. hemsleyanum is expected to form a sustainable development pathway from technical optimization to large-scale promotion and from resource conservation to industrial value enhancement.

Conflict of Interest Disclosure

The author affirms 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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