1 Introduction

Hang Baishao is the dried root of herbaceous peony (Paeonia lactiflora), a perennial herbaceous plant in the genus Paeonia of the family Ranunculaceae. It is a well-known authentic medicinal material. The plant features delicate flowers and lush foliage, and it is widely cultivated in China, particularly in the Zhejiang region (Zhao et al., 2012). The root of the Paeonia lactiflora serves as a medicinal component, known in traditional Chinese medicine as Baishao (Radix Paeoniae Alba) (Kang et al., 2020; Song et al., 2023). The most common types of Baishao available on the market are Hang Baishao and Hao Baishao. The former is primarily produced in Pan’an, Zhejiang, while the latter is mainly grown in Haozhou, Anhui. According to the Chinese Medicinal Materials Handbook, Baishao produced in Zhejiang is generally considered to be of the highest quality. As its primary distribution hub is in Hangzhou, it is referred to as "Hang Baishao" (Zhang et al., 2019a). It was reported that 'Hang Baishao' was the best performing and had the highest adaptability to the warm winters in Hangzhou, and it also had the earliest flowering development with high pollen quantity and activity. 'Hang Baishao' is the only peony cultivar that can be widely cultivated south of 30°N. Its exceptional ornamental performance not only validates its growth potential under warm winter conditions but also highlights its significant value in horticultural landscaping and scientific research.

Paeonia lactiflora 'Hang Baishao' root (Radix Paeoniae Alba) has been widely used in traditional Chinese medicine for its anti-inflammatory, analgesic, and sedative effects. It is recognized as one of the Chinese medicinal herbs "Zhe Ba Wei (Eight Genuine Herbs of Zhejiang)" (Bae et al., 2008; Tan et al., 2020; Song et al., 2023). Studies have shown that the total glucosides of peony (TGP), extracted from Radix Paeoniae Alba, exhibit anti-inflammatory, analgesic, and immunomodulatory effects, with paeoniflorin and albiflorin being the primary active components (Bae et al., 2008; Jiang et al., 2020). The absorption and metabolism of paeoniflorin and albiflorin are significantly influenced by the components of other herbs, particularly in formulas containing licorice, indicating that the interactions among different formula components can alter the pharmacological effects of Radix Paeoniae Alba (Gan et al., 2012). Albiflorin has also demonstrated notable antidepressant-like effects, with mechanisms potentially related to enhanced expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and the regulation of 5-HT/NE levels (Wang et al., 2016; Kong et al., 2018). Moreover, extracts of Radix Paeoniae Alba have been widely applied in the treatment of inflammation-related diseases such as nephropathy, liver diseases, and autoimmune disorders. Due to its mild effects and low side effects, it is an important component in traditional Chinese medicine. These studies provide a solid scientific basis for its extensive application in modern drug development. However, further optimization is needed in its cultivation, extraction, quality control, and clinical application.

Currently, the cultivation of Paeonia lactiflora 'Hang Baishao' is widespread in regions with suitable climates. Due to its dual value as an ornamental and medicinal plant, it generates significant economic benefits. Optimizing cultivation conditions, such as shade treatment and pH adjustment, can enhance both its aesthetic and medicinal qualities. Shade treatment can influence flower color and blooming period, while the pH of irrigation water has a notable impact on plant growth and flower quality (Zhao et al., 2012; Zhao et al., 2013). With advancements in cultivation techniques, such as in vitro callus induction and plant regeneration technologies, large-scale production has become feasible, improving the quality of the plants (Shen et al., 2012; Song et al., 2023). Different combinations of culture media and plant growth regulators (e.g., KT, TDZ, IBA) significantly affect callus formation, proliferation, and bud differentiation (Song et al., 2023). Additionally, research on embryonic tissue culture has successfully achieved embryo rescue through organogenesis, providing technical support for hybrid breeding of high-quality varieties (Zhao et al., 2017).

This study investigates the advancements in cultivation techniques for Paeonia lactiflora 'Hang Baishao' and assesses their effects on yield and quality. The study focuses on analyzing various agricultural practices, such as soil management and pest control, and their impact on the growth performance and quality of Paeonia lactiflora 'Hang Baishao', aiming to provide practical recommendations for growers to enhance both the quantity and quality of their yields. This study attends to establish a set of best practices for cultivators to enhance the ornamental and medicinal value of Paeonia lactiflora, thereby promoting its economic feasibility and sustainable development within the horticultural industry.

2 Biological Characteristics of Paeonia lactiflora 'Hang Baishao'

2.1 Morphological characteristics

Herbaceous peony (Paeonia lactiflora) 'Hang Baishao' has garnered widespread attention for its unique morphological characteristics. The plant has a well-developed root system, primarily consisting of thick fleshy roots that store nutrients and adapt to various soil types. Its above-ground parts consist of upright stems and pinnately compound leaves. The leaves are deep green, smooth, and exhibit elegant ornamental value. The flowers are large and colorful, with diverse petal shapes ranging from single to double layers, and colors spanning white, pink, and red, offering high ornamental appeal (Zhang et al., 2019a; Wang et al., 2022a). The fruit is a follicle, and the seeds are dark brown or reddish-brown, rich in oil content, serving as an important medium for plant reproduction (Figure 1).

In addition to its aesthetic appeal, Paeonia lactiflora has been observed to have a high pollen viability rate of 55.60%, making it an excellent candidate for hybridization efforts aimed at developing new cultivars with enhanced traits (Zhang et al., 2019a). This high pollen viability is a critical factor in its use as a male parent in breeding programs, contributing to the creation of hybrids that can thrive in warmer climates.

2.2 Growth and development conditions

The growth and development of P. lactiflora ‘Hang Baishao’ are influenced by multiple factors, including temperature, light, and soil conditions. The most suitable soil type is well-drained sandy loam or loam, with an optimal pH range of 6.5 to 7.5 (Zhang et al., 2019a). Enhancing the organic matter content in the soil significantly promotes root growth and development. P. lactiflora ‘Hang Baishao’ thrives in a cool and moist environment, requiring ample rainfall during the growing season, but excessive water accumulation can lead to root rot.

Low winter temperatures are crucial for the natural dormancy of P. lactiflora ‘Hang Baishao’, aiding in the regulation of bud differentiation and flowering time. The optimal chilling requirement (CR) for peonies is 672.00 to 856.08 chilling units (CUs), ensuring favorable performance in sprouting, growth, and flowering (Zhang et al., 2017; Wang et al., 2020). Controlled experiments have demonstrated that cold storage at 0 °C-4 °C for four weeks, combined with irrigation using 300 mg/L humic acid, is the most effective strategy for promoting flowering and maintaining flower quality (Zhang et al., 2019a). Windy conditions may cause damage to stems, leaves, and flowers; therefore, appropriate windbreak measures should be implemented. These findings underscore the importance of precise environmental control in optimizing the growth and development of P. lactiflora ‘Hang Baishao’.

2.3 Medicinal components and quality indicators

P. lactiflora ‘Hang Baishao’ is not only valued for its ornamental qualities but also for its medicinal components, which have been the subject of extensive research. The roots of P. lactiflora ‘Hang Baishao’ (Radix Paeoniae Alba) contain significant levels of total glucosides of paeony (TGP), which are known for their anti-inflammatory and immunomodulatory properties (Zaiyou et al., 2018; Jiang et al., 2020). These compounds, including paeoniflorin and albiflorin, are crucial for the medicinal applications of P. lactiflora ‘Hang Baishao’, particularly in the treatment of autoimmune diseases.

The quality indicators of P. lactiflora ‘Hang Baishao’ are closely linked to its metabolomic profile, which includes a diverse array of phenolic acids and flavonoids. These compounds contribute to the plant's medicinal efficacy and are influenced by the composition of root endophytes (Yang et al., 2023). By analyzing the microbiome and metabolome of P. lactiflora ‘Hang Baishao’, researchers can better understand the factors that affect its medicinal quality, paving the way for enhanced cultivation practices that maximize its therapeutic potential.

3 Traditional and Current Cultivation Techniques of P. lactiflora ‘Hang Baishao’

3.1 Review of traditional cultivation methods

Traditional cultivation methods of Paeonia lactiflora ‘Hang Baishao’ have primarily focused on adapting the plant to temperate regions with cool and dry climates. Historically, these methods have included selecting cultivars that naturally thrive in these conditions and ensuring that the plants receive adequate chilling during the winter months to break bud dormancy and promote flowering. The traditional approach has relied heavily on natural chilling, which is essential for the dormancy release and subsequent growth cycles of the Paeonia lactiflora ‘Hang Baishao’ (Zhang et al., 2017; Zhang et al., 2019a).

In regions where natural chilling is insufficient, traditional methods have often failed to produce optimal results. For instance, in the southern parts of China, where winter temperatures are higher, traditional cultivation techniques have struggled to meet the chilling requirements of Paeonia lactiflora ‘Hang Baishao’. This has led to poor bud dormancy release and reduced flowering, significantly impacting the yield and quality of the peonies (Zhang et al., 2019a).

3.2 Application of modern cultivation techniques

Modern cultivation techniques have introduced several innovative approaches to address the limitations of traditional methods. One significant advancement is the use of controlled chilling treatments to meet the chilling requirements of Paeonia lactiflora ‘Hang Baishao’ in warmer climates. Studies have shown that chilling at 0 °C-4 °C for four weeks, combined with irrigation using 300 mg/L humic acid, can effectively hasten flowering and ensure high-quality blooms (Zhang et al., 2019a; Kamenetsky-Goldstein and Yu, 2022). The application of plant growth regulators and optimized cultivation conditions further enhances the yield and quality of both flowers and roots, thereby increasing its economic potential (Bae et al., 2008; Zhao et al., 2021). 

Another modern technique involves the use of multi-criteria decision-making (MCDM) models to evaluate and select peony cultivars that are best suited for low-latitude regions. This approach integrates long-running quantitative observations and various criteria related to adaptability, ornamental features, and growth habits. Paeonia lactiflora ‘Hang Baishao’ has been identified as a highly adaptable herbaceous peony cultivar, making it an optimal candidate for cultivation in subtropical and tropical regions (Zhang et al., 2019b; Wang et al., 2020).

3.3 Challenges in cultivation technique development

Despite the advancements in modern cultivation techniques, several challenges remain in the development and application of these methods. One of the primary challenges is the variability in chilling requirements among different peony cultivars. While Paeonia lactiflora ‘Hang Baishao’ has a relatively low chilling requirement, other cultivars may not perform as well under the same conditions, necessitating further research and customization of chilling treatments (Zhang et al., 2017; Wang et al., 2022a).

Another significant challenge is the impact of global warming and extreme weather events on peony cultivation. Higher winter temperatures and unpredictable weather patterns can disrupt the dormancy and growth cycles of Paeonia lactiflora ‘Hang Baishao’, making it difficult to maintain consistent yield and quality. Additionally, the development of new cultivars through hybridization and genetic modification requires extensive research and testing to ensure that they can thrive in diverse climatic conditions (Zhang et al., 2019a; 2019b; Wang et al., 2022a).

4 Optimization Strategies for Cultivation Techniques of Paeonia lactiflora 'Hang Baishao'

4.1 Soil and fertilizer management techniques

The selection of appropriate soil is crucial for the successful cultivation of Paeonia lactiflora 'Hang Baishao'. Sun et al. (2022) conducted metabolomic and high-throughput sequencing analyses on soils from four major Paeonia lactiflora-producing regions in China (Pan'an in Zhejiang, Bozhou in Anhui, Zhongjiang in Sichuan, and Heze in Shandong). Their findings revealed that the rhizosphere microbial community and soil metabolites significantly influence the synthesis of secondary metabolites in Paeonia lactiflora roots, such as paeoniflorin. It is recommended to use well-drained, loamy soil with a neutral to slightly acidic pH to promote optimal growth and flowering. Soil improvement measures such as the incorporation of organic matter can enhance soil structure and fertility, which are essential for the healthy development of peony plants (Zhang et al., 2019a; Wang et al., 2020).

Fertilization strategies should focus on providing balanced nutrients to support the growth cycle of 'Hang Baishao'. The use of organic fertilizers, such as compost or well-rotted manure, can supply essential nutrients while improving soil health. Additionally, the application of humic acid has been shown to enhance flowering quality and hasten flowering when combined with chilling treatments (Zhang et al., 2019a). Regular soil testing can guide the adjustment of fertilizer types and application rates to meet the specific nutrient requirements of the plants (Zhang et al., 2017).

4.2 Planting density and field management

Optimal planting density is vital for maximizing yield and quality. Research indicates that maintaining an appropriate distance between plants can reduce competition for resources, thereby enhancing growth and flowering performance. Studies have shown that 'Hang Baishao' thrives in conditions where planting density is carefully managed to balance space and resource availability (Zhang et al., 2019b; Wang et al., 2022).

Field management practices such as mulching, irrigation, and weed control are essential for maintaining plant health and productivity. Mulching can help retain soil moisture and suppress weeds, while efficient irrigation systems ensure that plants receive adequate water without waterlogging. Regular monitoring and timely interventions are necessary to optimize these management measures and support the robust growth of 'Hang Baishao' (Zhang et al., 2019b; Wang et al., 2022).

4.3 Pest and disease management techniques

Common diseases affecting 'Hang Baishao' include fungal infections and root rot, which can be mitigated through proper sanitation and the use of disease-resistant cultivars. Implementing crop rotation and ensuring good air circulation around plants can also help prevent disease outbreaks. Fungicides may be used as a last resort to control severe infections (Meng et al., 2021; Chen et al., 2024).

Pests such as aphids and caterpillars can pose significant threats to 'Hang Baishao'. Integrated pest management (IPM) strategies, including the use of biological control agents and cultural practices, are effective in managing pest populations. Regular monitoring and the application of environmentally friendly pesticides can help maintain pest levels below damaging thresholds, ensuring the health and quality of the peony plants (Chen et al., 2024).

4.4 Application of new technologies and methods

In the cultivation of 'Hang Baishao', the application of new technologies and methods has achieved remarkable results in improving yield and quality. The integration of genetic and molecular biology approaches has provided deeper insights into the study of chilling requirements for 'Hang Baishao'. Transcriptome sequencing and gene identification have revealed key genes such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) and WRKY DNA-BINDING PROTEIN 33 (WRKY33), which may play significant roles in regulating chilling requirements (Figure 2) (Zhang et al., 2017; Wang et al., 2022b). Understanding these genetic factors can aid in developing novel varieties optimized for chilling requirements, enabling successful cultivation in warmer climates.

Combining hybridization techniques to develop new varieties with enhanced adaptability and performance is also a key approach. Hangzhou White Peony, known for its high pollen viability, is considered an excellent male parent, making it highly suitable for breeding programs aimed at improving traits such as flowering time and stress resistance (Zhang et al., 2019a). Furthermore, applying multi-criteria decision-making (MCDM) methods allows for the evaluation and selection of varieties that perform best under different climatic conditions, ensuring that cultivated plants achieve the highest adaptability and performance (Zhang et al., 2019b).

5 Impact of Cultivation Techniques on Yield and Quality of P. lactiflora ‘Hang Baishao’

5.1 Evaluation of the effectiveness of high-yield cultivation techniques

The effectiveness of high-yield cultivation techniques for P. lactiflora ‘Hang Baishao’ has been demonstrated through various studies. For instance, the introduction of chilling treatments and the use of growth regulators have shown significant improvements in flowering and growth. Specifically, chilling at 0 °C-4 °C for four weeks combined with irrigation using 300 mg/L humic acid was found to be the optimal combination for hastening flowering and ensuring high-quality blooms (Zhang et al., 2019a). This method not only promotes better bud dormancy release but also enhances the overall growth cycle of the plant, making it more adaptable to low-latitude regions with warmer winters (Zhang et al., 2019a; Wang et al., 2020).

Additionally, the integration of long-running quantitative observation (LQO) and multi-criteria decision-making (MCDM) approaches has been effective in evaluating the comprehensive performance of P. lactiflora ‘Hang Baishao’ in different climatic conditions. This approach has identified P. lactiflora ‘Hang Baishao’ as one of the most adaptable cultivars for southern growing regions, further validating the effectiveness of these high-yield cultivation techniques (Zhang et al., 2019b; Wang et al., 2022a). The use of these advanced evaluation methods ensures that the cultivation techniques are not only effective but also sustainable in the long term.

5.2 Enhancement effects on the content of medicinal components

The cultivation techniques employed for P. lactiflora ‘Hang Baishao’ have also shown significant enhancement effects on the content of its medicinal components. Studies have revealed that the albiflorin content, a key medicinal component, varies significantly between different populations of P. lactiflora ‘Hang Baishao’, with cultivated varieties showing higher concentrations compared to their wild counterparts (Wang et al., 2014; Jian et al., 2018). This indicates that specific cultivation techniques can be optimized to enhance the medicinal value of P. lactiflora. The growth conditions significantly affect the mineral and active component content in the roots of Hangzhou White Peony. For example, the iron and manganese content show a positive correlation with the total glycoside content, indicating that regulating soil mineral levels can enhance the medicinal quality of P. lactiflora ‘Hang Baishao’ (Li et al., 2019).

Moreover, comprehensive microbiome and metabolome analyses have shown that the medicinal cultivar P. lactiflora ‘Hang Baishao’ has a distinct profile of endophytic fungi and metabolites compared to ornamental varieties. The lower diversity and abundance of endophytic fungi in P. lactiflora ‘Hang Baishao’ are associated with higher concentrations of medicinal compounds like flavonoids and phenolic acids (Cheng et al., 2018; Yang et al., 2023). These findings suggest that targeted cultivation practices can significantly improve the medicinal quality of P. lactiflora ‘Hang Baishao’, making it a valuable resource for traditional and modern medicine.

5.3 Economic benefit analysis of technological improvements

The economic benefits of technological improvements in the cultivation of P. lactiflora ‘Hang Baishao’ are substantial. The introduction of advanced cultivation techniques, such as optimized chilling treatments and the use of growth regulators, has not only improved the yield and quality of the plant but also its economic viability. For instance, the successful adaptation of P. lactiflora ‘Hang Baishao’ to low-latitude regions has expanded its growing area, thereby increasing its market availability and economic value (Zhang et al., 2019a; 2019b). 

Furthermore, the development of a multi-criteria decision-making (MCDM) model for evaluating the performance of P. lactiflora ‘Hang Baishao’under different climatic conditions has provided a cost-effective and time-saving method for selecting high-quality germplasm. This model has identified P. lactiflora ‘Hang Baishao’as a top-performing cultivar, which can be promoted for large-scale cultivation, thereby enhancing its economic returns (Wang et al., 2022a). The combination of these technological advancements ensures that the cultivation of P. lactiflora ‘Hang Baishao’ is not only sustainable but also economically profitable.

6 Case Studies

6.1 Development and optimization of an efficient regeneration system for P. lactiflora ‘Hang Baishao’

Paeonia lactiflora is a perennial herbaceous plant with both ornamental and medicinal value. However, its traditional propagation methods are time-consuming and inefficient, making it challenging to meet large-scale production demands. Tissue culture technology offers an effective approach for the rapid propagation and germplasm preservation of peony, making the establishment of an efficient and stable regeneration system a key research focus.

Song et al. (2023) developed an efficient regeneration system for Paeonia lactiflora through systematic optimization of culture conditions and plant growth regulators. During the callus induction phase, cotyledons used as explants combined with MS medium supplemented with appropriate concentrations of 6-BA, NAA, 2,4-D, or PIC achieved the highest induction rate of 98.89%, with high-quality callus and significantly reduced browning. In the bud differentiation phase, the combination of TDZ and NAA significantly improved the differentiation rate of adventitious buds, which grew robustly. During the rooting phase, IBA demonstrated superior root-promoting ability, achieving a rooting rate of 38.89% at a concentration of 1.0 mg/L (Figure 3). These improvements significantly enhanced the overall regeneration efficiency of Paeonia lactiflora.

This study addressed critical technical bottlenecks in peony plant regeneration, including low induction rates, browning, and low regeneration efficiency, laying a foundation for large-scale production and genetic improvement of peony. Nevertheless, further optimization of adventitious bud differentiation and rooting rates is required, providing direction for future research. Overall, this system shows significant potential for germplasm preservation, rapid propagation, and genetic engineering applications of Paeonia lactiflora.

6.2 Optimization strategies for forcing cultivation of ‘Hang Baishao’

The cultivation study of ‘Hang Baishao’ aims to enhance its yield and adaptability, particularly in low-latitude regions. In such areas, warm winter climates hinder bud dormancy release and normal flowering. To overcome this challenge, Zhang et al. (2019a) investigated multiple forcing cultivation strategies, including low-temperature treatment and the combined application of 5-azacytidine and GA3, to optimize flowering time and quality, thereby improving its commercial value. The study revealed that ‘Hang Baishao’ exhibits strong adaptability to warm winter climates in regions like Zhejiang, with a high pollen viability of 55.6%, making it an excellent male parent for hybridization. However, despite good growth, hybrid offspring commonly exhibited flower bud abortion, indicating the need for further optimization of breeding strategies. Moreover, combining chilling treatments with 300 mg/L humic acid irrigation effectively advanced flowering and improved flower quality. Plants treated with artificial chilling and humic acid demonstrated the best performance, achieving early flowering in mid-February and exhibiting excellent ornamental and commercial value (Figure 4).

This study systematically addressed the cultivation challenges of peonies in warm winter regions and proposed feasible solutions. On one hand, introducing varieties and hybrid breeding can produce new cultivars with low chilling requirements. On the other hand, employing chilling and exogenous hormone-assisted forcing cultivation techniques enables year-round production of cut flowers and potted peonies. This integrated indoor and outdoor strategy offers valuable insights for the application of other economically significant plants with winter dormancy traits in low-latitude regions.

7 Future Directions in Cultivation Research

7.1 Prospects for smart agriculture technologies

The integration of smart agriculture technologies presents a promising future direction for the cultivation of Paeonia lactiflora 'Hang Baishao'. These technologies, including precision farming tools, IoT-based monitoring systems, and automated irrigation, can significantly enhance the efficiency and effectiveness of peony cultivation (Zhang et al., 2017; Chen et al., 2024). For instance, the use of sensors to monitor soil moisture and nutrient levels can optimize irrigation schedules and fertilizer application, ensuring that plants receive the right amount of water and nutrients at the right time. This can lead to improved plant health and increased yields (Zhang et al., 2019a; Wang et al., 2020).

Moreover, the application of data analytics and machine learning algorithms can help in predicting plant growth patterns and identifying potential issues before they become problematic. By analyzing data collected from various sensors and environmental conditions, farmers can make informed decisions to mitigate risks and enhance the overall quality of the peonies. The adoption of these advanced technologies can also reduce labor costs and increase the scalability of peony cultivation, making it more economically viable (Zhang et al., 2019b; Wang et al., 2022a).

7.2 Application of genetic improvement in cultivation

Genetic improvement through hybridization and biotechnological approaches holds significant potential for enhancing the cultivation of Paeonia lactiflora 'Hang Baishao'. Hybridization efforts have already shown promise in creating new cultivars with desirable traits such as increased adaptability to warmer climates and improved flowering capabilities. For example, 'Hang Baishao' has been identified as an excellent male parent in hybridization due to its high pollen viability, which can be leveraged to develop new cultivars with enhanced traits (Zhang et al., 2019a; Wang et al., 2022b).

In addition to traditional breeding methods, modern genetic engineering techniques such as CRISPR/Cas9 can be employed to introduce specific genes that confer resistance to diseases, pests, and environmental stresses. This can lead to the development of peony cultivars that are more resilient and require fewer inputs, thereby reducing the environmental impact of cultivation. Furthermore, understanding the genetic basis of key traits such as bud dormancy release and chilling requirements can facilitate the selection and breeding of cultivars that are better suited to low-latitude regions (Wang et al., 2020; Song et al., 2023).

7.3 Sustainability and ecological cultivation

Sustainability and ecological cultivation practices are essential for the long-term viability of Paeonia lactiflora 'Hang Baishao' cultivation. Implementing sustainable practices such as organic farming, integrated pest management (IPM), and the use of renewable resources can minimize the environmental footprint of peony cultivation. For instance, the use of organic fertilizers and natural pest control methods can reduce the reliance on chemical inputs, promoting a healthier ecosystem (Zhang et al., 2019b; Wang et al., 2022a).

Additionally, adopting ecological cultivation techniques such as crop rotation, intercropping, and conservation tillage can improve soil health and biodiversity. These practices can enhance the resilience of the cultivation system to environmental stresses and reduce the risk of soil degradation (Deng et al., 2022; Singh et al., 2024). Research into the ecological interactions between peonies and their surrounding environment can provide valuable insights into optimizing these practices for better yield and quality. By prioritizing sustainability, the cultivation of 'Hang Baishao' can contribute to the conservation of natural resources and the promotion of environmental stewardship (Wang et al., 2022b; Song et al., 2023).

8 Concluding Remarks

The cultivation techniques for Paeonia lactiflora 'Hang Baishao' have seen significant advancements, particularly in adapting the plant to low-latitude regions with warmer winters. Key findings include the identification of 'Hang Baishao' as a cultivar with a low chilling requirement (CR), making it suitable for southern growing regions. The use of growth regulators and specific chilling and irrigation treatments has been shown to optimize flowering and ensure quality. Additionally, the integration of long-running quantitative observation (LQO) and multi-criteria decision-making (MCDM) approaches has proven effective in evaluating the comprehensive performance of 'Hang Baishao' and other cultivars in subtropical climates.

The advances in cultivation techniques for 'Hang Baishao' are significant for several reasons. They enable the expansion of peony cultivation into regions previously considered unsuitable due to warmer winter climates, thereby increasing the economic value and ornamental application of the plant. At the same time, the development of reliable models for evaluating chilling requirements and the use of growth regulators provide a scientific basis for optimizing cultivation practices. The future of 'Hang Baishao' cultivation looks promising, with ongoing research likely to yield further improvements in yield and quality. The successful adaptation of 'Hang Baishao' to low-latitude regions sets a precedent for the introduction of other temperate plants into subtropical and tropical areas. Continued refinement of chilling treatments, growth regulators, and evaluation models will enhance the plant's adaptability and resilience to climate change. Moreover, the integration of advanced genetic studies could unlock new traits that further optimize the plant's performance in diverse environmental conditions.

The advancements in the cultivation techniques of Paeonia lactiflora 'Hang Baishao' have not only improved its yield and quality but also expanded its growing range to include low-latitude regions. These developments are crucial for the economic and ornamental value of the plant and provide a model for the adaptation of other temperate plants to warmer climates. Future research and technological innovations will likely continue to enhance the cultivation and application of 'Hang Baishao', making it a valuable addition to horticulture in diverse climatic conditions.

Acknowledgments

The authors sincerely thank Dr. Cai for reviewing the manuscript and providing valuable suggestions, which contributed to its improvement. Additionally, heartfelt gratitude is extended to the two anonymous peer reviewers for their comprehensive evaluation of the manuscript.

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.

Reference

Bae S.G., Kim J.H., Park S.J., and Kim J.C., 2008, Influence of forcing cultivation time on cut flower, root quality, and yield in peony (Paeonia lactiflora Pall. cv. Taebaek), Korean Journal of Medicinal Crop Science, 16(6): 421-426.

Chen X., Li D., Guo J., Wang Q., Zhang K., Wang X., Shao L., Luo C., Xia Y., and Zhang J., 2024, Identification and analysis of the Superoxide Dismutase (SOD) gene family and potential roles in high-temperature stress response of herbaceous peony (Paeonia lactiflora Pall.), Antioxidants, 13(9): 1128. 

https://doi.org/10.3390/antiox13091128

Cheng X., Wei Z., Pu S., Xiang M., Yan A., Zhang Y., and Wang X., 2018, Diversity of endophytic fungi of Paeonia lactiflora Pallas and screening for fungal paeoniflorin producers, FEMS Microbiology Letters, 365(24): fny263. 

https://doi.org/10.1093/femsle/fny263

Deng X., Yang Q., Zhang D., and Dong S., 2022, Application of conservation tillage in China: a method to improve climate resilience, Agronomy, 12(7): 1575. 

https://doi.org/10.3390/agronomy12071575

Gan P., Zhong M., Huang X., Sun M., Wang Y., Xiao Y., Zeng C., Yuan Q., Liu Z., and Zhou H., 2011, Pharmacokinetic comparisons of albiflorin and paeoniflorin after oral administration of Shaoyao-Gancao-Tang and single herb Peony decoction to rats, Planta Medica, 78(3): 237-243. 

https://doi.org/10.1055/s-0031-1280366

Jiang H., Li J., Wang L., Wang S., Nie X., Chen Y., Fu Q., Jiang M., Fu C., and He Y., 2020, Total glucosides of peony: a review of its phytochemistry, role in autoimmune diseases, and mechanisms of action, Journal of Ethnopharmacology, 258: 112913. 

https://doi.org/10.1016/j.jep.2020.112913

Kamenetsky-Goldstein R., and Yu X., 2022, Cut peony industry: the first 30 years of research and new horizons, Horticulture Research, 9: uhac079. 

https://doi.org/10.1093/hr/uhac079

Kang L., Miao J.X., Cao L.H., Miao Y.Y., Liu H.J., Xiang L.L., and Song Y.G., 2020, Total glucosides of herbaceous peony (Paeonia lactiflora Pall.) flower attenuate adenine-and ethambutol-induced hyperuricaemia in rats, Journal of Ethnopharmacology, 261: 113054. 

https://doi.org/10.1016/j.jep.2020.113054

Kong M., Liu H.H., Wu J., Shen M.Q., Wang Z.G., Duan S.M., Zhang Y., Zhu H., and Li S.L., 2018, Effects of sulfur-fumigation on the pharmacokinetics, metabolites and analgesic activity of Radix Paeoniae Alba, Journal of Ethnopharmacology, 212: 95-105. 

https://doi.org/10.1016/j.jep.2017.10.023

Li Z., Liu D., Zhan L., and Li L., 2020, Mineral elements and active ingredients in root of wild Paeonia lactiflora growing at Duolun County, Inner Mongolia, Biological Trace Element Research, 193: 548-554. 

https://doi.org/10.1007/s12011-019-01725-3

Meng J.S., Tang Y.H., Sun J., Zhao D.Q., Zhang K.L., and Tao J., 2021, Identification of genes associated with the biosynthesis of unsaturated fatty acid and oil accumulation in herbaceous peony ‘Hangshao’ (Paeonia lactiflora ‘Hangshao’) seeds based on transcriptome analysis, BMC Genomics, 22: 1-21. 

https://doi.org/10.1186/s12864-020-07339-7

Shen M., Wang Q., Yu X., and da Silva J.A.T., 2012, Micropropagation of herbaceous peony (Paeonia lactiflora Pall.), Scientia Horticulturae, 148: 30-38. 

https://doi.org/10.1016/J.SCIENTA.2012.09.017

Song W., Song Y., Liu X., Zhang X., Xin R., Duan S., Guan S., and Sun X., 2023, Improvement of Culture Conditions and Plant Growth Regulators for In Vitro Callus Induction and Plant Regeneration in Paeonia lactiflora Pall., Plants, 12(23): 3968. 

https://doi.org/10.3390/plants12233968

Sun X., Zhang X., Zhang G., Miao Y., Zeng T., Zhang M., Zhang H., Zhang L., and Huang L., 2022, Environmental response to root secondary metabolite accumulation in Paeonia lactiflora: insights from rhizosphere metabolism and root-associated microbial communities, Microbiology Spectrum, 10(6): e02800-22. 

https://doi.org/10.1128/spectrum.02800-22

Singh N.K., Sachan K., BP M., Panotra N., and Katiyar D., 2024, Building Soil Health and Fertility through Organic Amendments and Practices: A Review, Asian Journal of Soil Science and Plant Nutrition, 10(1): 175-197. 

https://doi.org/10.9734/ajsspn/2024/v10i1224

Tan Y.Q., Chen H.W., Li J., and Wu Q.J., 2020, Efficacy, chemical constituents, and pharmacological actions of Radix Paeoniae Rubra and Radix Paeoniae Alba, Frontiers in Pharmacology, 11: 1054. 

https://doi.org/10.3389/fphar.2020.01054

Wang J., Zhang X., and Hu Y., 2023, Accumulation and health risk of major and trace elements in a soil–medicinal plant system: a case study of the Chinese herbaceous peony (Paeonia lactiflora Pall.) grown in Bozhou, China, Geochemistry: Exploration, Environment, Analysis, 23(2): geochem2023-006. 

https://doi.org/10.1144/geochem2023-006

Wang Q., Xiao P., Luo K., Song J., Wei S., Jian Z., Hou J., Peng Y., and Wang W., 2014, Genetic and component content differentiation between wild and cultivated populations of Paeonia lactiflora and related species used as Chishao and Baishao in China, Biological and Pharmaceutical Bulletin, 37(9): 1516-1524. 

https://doi.org/10.1248/BPB.B14-00335

Wang X., Li D., Zhang D., Shi X., Wu Y., Qi Z., Ding H., Zhu K., Xia Y., and Zhang J., 2020, Improving crucial details and selecting the optimal model for evaluating the chilling requirement of Paeonia lactiflora Pall. at low latitudes during four winters, Scientia Horticulturae, 265: 109175. 

https://doi.org/10.1016/j.scienta.2020.109175

Wang X., Zhang R., Huang Q., Shi X., Li D., Shao L., Xu T., Horvath D., Xia Y., and Zhang J., 2022b, Comparative study on physiological responses and gene expression of bud endodormancy release between two herbaceous peony cultivars (Paeonia lactiflora Pall.) with contrasting chilling requirements, Frontiers in Plant Science, 12: 772285. 

https://doi.org/10.3389/fpls.2021.772285

Wang X., Zhang R., Zhang K., Shao L., Xu T., Shi X., Li D., Zhang J., and Xia Y., 2022a, Development of a multi-criteria decision-making approach for evaluating the comprehensive application of herbaceous peony at low latitudes, International Journal of Molecular Sciences, 23(22): 14342. 

https://doi.org/10.3390/ijms232214342

Wang Y.L., Wang J.X., Hu X.X., Chen L., Qiu Z.K., Zhao N., Yu Z., Sun S., Xu Y., Guo Y., Liu C., Zhang Y., Li Y., and Yu C., 2016, Antidepressant-like effects of albiflorin extracted from Radix Paeoniae Alba, Journal of Ethnopharmacology, 179: 9-15. 

https://doi.org/10.1016/j.jep.2015.12.029

Yang L., Zhou M., Zu M., Zuo J., and Yuan Y., 2023, Comprehensive microbiome and metabolome analyses reveal the medicinal components of Paeonia lactiflora, Plants, 12(8): 1612. 

https://doi.org/10.3390/plants12081612

Zhang J., Li D., Shi X., Zhang D., Qiu S., Wei J., Zhang J., Zhou J., Zhu K., and Xia Y., 2017, Mining and expression analysis of candidate genes involved in regulating the chilling requirement fulfillment of Paeonia lactiflora ‘Hang Baishao’, BMC Plant Biology, 17: 1-21. 

https://doi.org/10.1186/s12870-017-1205-1

Zhang J., Wang X., Zhang D., Qiu S., Wei J., Guo J., Li D., and Xia Y., 2019b, Evaluating the comprehensive performance of Herbaceous Peonies at low latitudes by the integration of long-running quantitative observation and multi-criteria decision making approach, Scientific Reports, 9(1): 15079. 

https://doi.org/10.1038/s41598-019-51425-0

Zhang J., Zhang D., Wei J., Shi X., Ding H., Qiu S., Guo J., Li D., Zhu K., Horvath D., and Xia Y., 2019a, Annual growth cycle observation, hybridization and forcing culture for improving the ornamental application of Paeonia lactiflora Pall. in the low-latitude regions, PLOS One, 14(6): e0218164. 

https://doi.org/10.1371/journal.pone.0218164

Zaiyou J., Jingbo Y., Wenquan W., and Ning W., 2018, Effect of circumstances and process on the content of chemical components in Bai shao (Paeonia lactiflora Pall.), Bangladesh Journal of Botany, 47(1): 89-96.

Zhao D., Hao Z., and Tao J., 2012, Effects of shade on plant growth and flower quality in the herbaceous peony (Paeonia lactiflora Pall.), Plant Physiology and Biochemistry, 61: 187-196. 

https://doi.org/10.1016/j.plaphy.2012.10.005

Zhao D., Xu C., Luan Y., Shi W., Tang Y., and Tao J., 2021, Silicon enhances stem strength by promoting lignin accumulation in herbaceous peony (Paeonia lactiflora Pall.), International Journal of Biological Macromolecules, 190: 769-779. 

https://doi.org/10.1016/j.ijbiomac.2021.09.016

Zhao D., Xue Y., Shi M., and Tao J., 2017, Rescue and in vitro culture of herbaceous peony immature embryos by organogenesis, Scientia Horticulturae, 217: 123-129. 

https://doi.org/10.1016/J.SCIENTA.2017.01.040