Medicinal Plant Research 2026, Vol.16, No.3 http://hortherbpublisher.com/index.php/mpr © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved.
Medicinal Plant Research 2026, Vol.16, No.3 http://hortherbpublisher.com/index.php/mpr © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Publisher HortHerb Publisher Editedby Editorial Team of Medicinal Plant Research Email: edit@mpr.hortherbpublisher.com Website: http://hortherbpublisher.com/index.php/mpr Address: 11388 Stevenston Hwy, PO Box 96016, Richmond, V7A 5J5, British Columbia Canada Medicinal Plant Research (ISSN 1927-6508) is an open access, peer reviewed journal published online by HortHerb Publisher. The journal publishes all the latest and outstanding research articles, letters and reviews in all aspects of medicinal plant research, including plant growth and development, plant biology, plant nutrition, medicinal properties, phytochemical constituents, fitoterapia, pharmacognosy, essential oils, ethno- pharmacology agronomic management, and phytomedicine, as well as chemistry, pharmacology and use of medicinal plants and their derivatives. HortHerb Publisher is an international Open Access publisher specializing in horticulture, herbal sciences, and tea-related research registered at the publishing platform that is operated by Sophia Publishing Group (SPG), founded in British Columbia of Canada. All the articles published in Medicinal Plant Research are Open Access, and are distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. HortHerb Publisher uses CrossCheck service to identify academic plagiarism through the world’s leading plagiarism prevention tool, iParadigms, and to protect the original authors’ copyrights.
Medicinal Plant Research (online), 2026, Vol. 16, No.3 ISSN 1927-6508 http://hortherbpublisher.com/index.php/mpr © 2026 HortHerb Publisher, registered at the publishing platform that is operated by Sophia Publishing Group, founded in British Columbia of Canada. All Rights Reserved. Latest Content Effects of Different Cultivation Substrates on the Growth and Quality Formation of Dendrobium officinale Xinchao Cao Medicinal Plant Research, 2026, Vol. 16, No. 3, 169-189 Analysis of the Integrated Development Pathways between Medicinal and Edible Utilization of Polygonatumand Understory Cultivation Industry XiaominYu Medicinal Plant Research, 2026, Vol. 16, No. 3, 190-204 Construction of an Efficient Production and Quality Control Technology System for Ganoderma lucidumSpore Powder Xianjun Jiang Medicinal Plant Research, 2026, Vol. 16, No. 3, 205-220 Development of Local Characteristic Resources of Tetrastigma hemsleyanumand Optimization of Under-Forest Industry Development Pathways Jianhui Li Medicinal Plant Research, 2026, Vol. 16, No. 3, 221-236 Effects of Organic Fertilizer Substitution for Chemical Fertilizers on Yield and Quality Formation of Atractylodes macrocephala Guangman Xu Medicinal Plant Research, 2026, Vol. 16, No. 3, 237-252
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 169 Feature Review Open Access Effects of Different Cultivation Substrates on the Growth and Quality Formation of Dendrobium officinale Xinchao Cao Caonong Herbal Health Food Business Department, Lin'an District, Hangzhou, 311300, Zhejiang, China Corresponding email: 994954377@qq.com Medicinal Plant Research, 2026, Vol.16, No.3 doi: 10.5376/mpr.2026.16.0011 Received: 15 Mar., 2026 Accepted: 18 Apr., 2026 Published: 06 May, 2026 Copyright © 2026 Cao, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Cao X.C., 2026, Effects of different cultivation substrates on the growth and quality formation of Dendrobium officinale, Medicinal Plant Research, 16(3): 169-189 (doi: 10.5376/mpr.2026.16.0011) Abstract Dendrobium officinale Kimura et Migo is an important medicinal and edible traditional Chinese medicinal resource. During artificial cultivation, substrate conditions directly affect plant growth, bioactive compound accumulation, and medicinal quality formation. This review systematically summarizes the types, characteristics, and application effects of different cultivation substrates, including sphagnum moss, bark, coconut coir, peanut shells, rice husks, perlite, ceramsite, and composite substrates. It focuses on their effects on seedling survival, plant vigor, root development, biomass accumulation, and dry matter distribution in D. officinale, and further discusses the regulatory effects of substrates on the formation of quality-related constituents, such as polysaccharides, dendrobine, flavonoids, and phenolic compounds. Studies have shown that suitable cultivation substrates can promote root growth and nutrient uptake by improving rhizosphere moisture, aeration, nutrient supply, and microbial environment, thereby increasing plant biomass and the accumulation of medicinally active compounds. Composite substrates have great application potential in high-quality and efficient cultivation of D. officinale because they integrate water retention, aeration, physical support, and nutrient buffering functions. However, current research still faces problems such as inconsistent substrate evaluation standards, insufficient elucidation of quality formation mechanisms, and weak integration between substrate formulations and industrial applications. Future studies should strengthen the development of environmentally friendly composite substrates, further investigate substrate-microbe-quality formation mechanisms, and integrate smart agricultural technologies to establish standardized, large-scale, and sustainable cultivation systems for D. officinale. Keywords Dendrobium officinale; Cultivation substrate; Growth and development; Quality formation; Bioactive compounds; Composite substrate 1 Introduction Dendrobium officinale Kimura et Migo is a perennial epiphytic herb of the genus Dendrobium in the family Orchidaceae. It is also a valuable traditional Chinese medicinal plant and a medicinal-edible resource in China. Its stems have been officially recorded in the Chinese Pharmacopoeia and can be developed and utilized as both Chinese medicinal materials and functional food resources. Traditional medicine holds that D. officinale has the effects of nourishing Yin, clearing heat, benefiting the stomach, promoting fluid production, and strengthening the viscera. Modern studies have further shown that it is rich in various bioactive components, including polysaccharides, alkaloids, flavonoids, bibenzyls, phenanthrenes, and phenolic compounds, and exhibits multiple biological functions such as antioxidant, anti-inflammatory, immunomodulatory, gastrointestinal-protective, hypoglycemic, antitumor, cardiovascular-protective, and neuroprotective effects (Xu et al., 2022; Wang et al., 2025). In recent years, with the rapid development of the health industry, traditional Chinese medicine industry, and functional food market, the demand for D. officinale has continued to increase. It has gradually transformed from a rare wild resource into a large-scale artificially cultivated crop and has become an important medicinal plant industry with high economic value (Hou et al., 2025). However, due to long-term overharvesting, habitat destruction, and slow natural regeneration, wild resources have declined significantly, and artificial cultivation, facility cultivation, and wild-simulated cultivation have gradually become the main sources of raw materials for D. officinale production (Chen et al., 2021; Liu et al., 2025). Alongside rapid industrial development, differences in cultivation regions, cultivation modes, harvest years, and
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 170 processing methods have resulted in obvious variations in product quality. Therefore, how to coordinate yield improvement with quality optimization under artificial cultivation conditions has become an important issue in both industrial development and scientific research on D. officinale (Yuan et al., 2020; Zhang et al., 2023). D. officinale is a typical epiphytic plant. Under natural conditions, it often grows attached to tree trunks, rock crevices, and other special habitats, and its roots have high requirements for the aeration, water retention, drainage, nutrient retention, and microecological environment of the growth medium. Therefore, in artificial cultivation systems, cultivation substrates are not only physical supports for plant attachment and growth, but also important factors regulating rhizosphere moisture, air, nutrients, and microbial environments. The commonly used substrates for D. officinale cultivation include pine bark, fern roots, sphagnum moss, biochar, mushroom residues, vermiculite, perlite, coconut coir, peanut shells, and composite substrates. These materials can, to some extent, simulate natural epiphytic habitats and provide roots with aeration, drainage, moisture retention, and nutrient-buffering conditions (He et al., 2022). Because different substrates vary significantly in pore structure, water-holding capacity, pH, nutrient content, and microbial composition, they exert important effects on root development, plant height, stem diameter, biomass accumulation, photosynthesis, stress resistance, and other growth indicators of D. officinale (Zhang et al., 2024). Previous studies have shown that pine bark-based substrates can improve the survival rate, plant height, stem girth, and dry weight of D. officinale, and show good production potential in some cultivation environments. Mixed substrates composed of pine bark and fern fiber can also support high acclimatization survival rates of tissue-cultured plantlets and favorable ex vitro growth performance (Luan et al., 2021; Wang et al., 2025). Meanwhile, substrates interact with ecological factors such as temperature, humidity, light, and nutrient status, thereby influencing the accumulation of polysaccharides, alkaloids, flavonoids, and other secondary metabolites, and ultimately determining the medicinal quality and commercial value of D. officinale (Yuan et al., 2020). This review examines the effects of different cultivation substrates on the growth and quality formation of D. officinale. In recent years, related research has gradually expanded from simple comparisons of cultivation effects among different substrates to multiple aspects, including substrate physicochemical properties, rhizosphere microbial communities, ecological factor interactions, and quality formation mechanisms. Existing studies have shown that substrate selection and cultivation mode jointly affect the growth performance, survival rate, stress resistance, and bioactive compound accumulation of D. officinale. However, current research still has certain limitations. Many studies focus on single substrate formulations, specific regions, or individual indicators such as polysaccharide content, lacking systematic integration of multi-component quality evaluation involving polysaccharides, alkaloids, flavonoids, and phenolic compounds. In addition, the relationships among substrate characteristics, ecological factors, metabolite profiles, and molecular regulatory mechanisms have not yet been fully clarified, and substrate evaluation standards and industrial application specifications still require further improvement. Based on a review of relevant domestic and international studies, this paper systematically summarizes the types and characteristics of commonly used cultivation substrates for D. officinale, focuses on analyzing the effects of different substrates and related cultivation modes on plant growth and development, bioactive compound accumulation, and quality formation, and further discusses the possible mechanisms by which substrates regulate growth and quality, current research problems, and future development directions. This review aims to provide theoretical references and practical guidance for the scientific selection of cultivation substrates, optimization of artificial cultivation systems, and standardized, high-quality, and sustainable development of the D. officinale industry. 2 Types of Common Cultivation Substrates for Dendrobium officinale 2.1 Natural organic substrates such as sphagnum moss and bark Natural organic substrates are widely used in the artificial cultivation of Dendrobium officinale. They are mainly derived from plant residues or natural organic materials and generally have good water retention, aeration, and root-attachment capacity, allowing them to partly simulate the natural epiphytic habitat of D. officinale. Among them, sphagnum moss is commonly used during tissue-cultured plantlet transplantation, seedling hardening, and
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 171 greenhouse nursery stages because of its loose texture, strong water absorption capacity, favorable pore structure, and suitable pH. Studies have shown that, during the hardening stage of D. officinale, pure sphagnum moss promotes faster root emergence, enhances tillering, produces thicker leaves and stems, and increases plant biomass compared with bark alone, while maintaining a similar root-shoot ratio, indicating its clear role in promoting early adaptation and recovery growth of seedlings. In addition, compared with bark-based substrates, sphagnum moss substrates can also increase chlorophyll, carotenoid, and polysaccharide contents, suggesting that they not only favor vegetative growth but may also promote the accumulation of medicinal components. Bark-based substrates mainly include pine bark, fir bark, and related materials, and are commonly used in seedbed cultivation, pot cultivation, and wild-simulated cultivation of D. officinale. Pine bark has high porosity and strong drainage capacity, providing a favorable aerated environment for the aerial roots of D. officinale and reducing the risk of root decay caused by prolonged high humidity. Meanwhile, during slow decomposition, pine bark can release certain organic nutrients and support sustained plant growth. Previous studies have shown that pine bark is widely used as an important component of seedbeds and mixed substrates for D. officinale. Under field-like cultivation conditions, it can support high survival rates, rapid growth, and high stem yield. During tissue-cultured plantlet acclimatization, the combined use of pine bark and fern fiber can achieve a 100% survival rate and favorable greenhouse growth performance inD. officinale (Luan et al., 2021). From the perspective of quality formation, bark-based substrates may also affect the accumulation of secondary metabolites in D. officinale. Zuo et al. (2020) conducted metabolomic analysis of D. officinale stems cultivated in pine bark, coconut coir, and a 1:1 mixture of the two substrates, and found that pine bark alone was more conducive to the accumulation of flavonoids, with “flavonoid biosynthesis” identified as the main regulated pathway. This indicates that natural organic substrates not only affect root attachment and plant growth, but may also participate in quality formation by altering the rhizosphere environment and metabolic status. However, natural organic substrates still have certain limitations. For example, sphagnum moss largely depends on natural harvesting, and long-term use may face pressures related to resource conservation and rising costs. Bark-based substrates also have limited nutrient content, a long decomposition cycle, and considerable batch-to-batch variation. Therefore, improving the utilization efficiency of natural organic substrates and developing alternative, sustainable composite materials have become important directions in substrate research for D. officinale. 2.2 Agricultural waste-based substrates such as coconut coir, peanut shells, and rice husks With the development of agricultural waste recycling and green cultivation concepts, agricultural by-products such as coconut coir, peanut shells, rice husks, mushroom residues, corncobs, and wood chips have gradually been applied in the cultivation of D. officinale andother Dendrobiumspecies. These substrates are widely available and relatively low in cost. They can reduce environmental pressure caused by agricultural waste accumulation while lowering cultivation costs, and therefore have good ecological value and industrial application potential. Coconut coir and coconut husk are common organic substrates in Dendrobium orchid cultivation. Owing to their strong water-holding capacity, high porosity, and suitable aeration, they can support favorable survival and growth performance (Nuammee et al., 2024; Tt et al., 2024; Olasehinde, 2025). In D. officinale cultivation, coconut coir can be used alone or mixed with materials such as pine bark. Zuo et al. (2020) found that, compared with pure pine bark, coconut coir alone or a 1:1 mixture of coconut coir and pine bark altered the stem metabolite profile of D. officinale but did not change the types of metabolites, indicating that it mainly affected metabolite contents rather than composition. In ornamental Dendrobiumcultivars, pure coconut husk substrates can increase plant height, shoot number, inflorescence length, and floret number, and their overall performance is superior to that of most mixed substrates. This further demonstrates the importance of an appropriate water-air balance for the growth of Dendrobium plants (Tt et al., 2024). Therefore, coconut coir substrates have good substitution potential in green cultivation systems for D. officinale. Peanut shells, rice husks, and other agricultural residues also have the advantages of light weight, good aeration, and structural improvement. After crushing, fermentation, composting, or disinfection, these materials can be used
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 172 alone as cultivation substrates or combined with bark, sphagnum moss, perlite, and other materials. Previous studies have used spent mushroom residues, Chinese herbal residues, chestnut shells, peanut shells, mulberry branches, corncobs, wood chips, and soil or clay amendments to construct granular substrates for D. officinale. The results showed that such composite substrates significantly improved disease resistance and root health, increased the survival rate to more than 98%, and enhanced plant height, stem diameter, polysaccharide content, and yield. Rice husks and related materials are also considered effective structural improvement and moisture-regulating components in substrates for Dendrobiumand other soilless crops (Figure 1) (Rahman et al., 2021; Hou et al., 2025). However, the application performance of agricultural waste-based substrates is greatly affected by raw material source, processing method, fermentation degree, and salt content. Insufficiently treated materials may carry risks such as pathogen residues, unbalanced nutrient release, or phytotoxicity. Therefore, in production practice, raw material pretreatment, fermentation and composting, sterilization, and scientific formulation should be strengthened to improve substrate stability and safety. Figure 1 The growth of Dendrobium Shavin White orchid seedling in different substrate (Adopted from Rahman et al., 2021) Image caption: A-T1; Rice husk+Chitosan, B-T3; Oil palm EFB+Chitosan, C-T4; Rice husk+Peat moss+Chitosan, D-T5; Rice husk+Peat moss+Oil palm EFB+Chitosan. Bar=1cm (Adopted from Rahman et al., 2021)
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 173 2.3 Perlite, ceramsite, and composite cultivation substrates Inorganic substrates have attracted attention in facility cultivation and composite substrate construction for D. officinale because of their good physical stability, low bulk density, high porosity, and long service life. Perlite is a porous inert material produced by high-temperature expansion. It is lightweight and has strong drainage and good aeration, which can improve substrate structure and reduce the risk of compaction caused by long-term cultivation. Ceramsite, brick and tile fragments, charcoal, expanded minerals, and related materials are also commonly used as structural components to enhance mechanical support and root-zone aeration. Studies have shown that perlite and similar inert mineral materials are common inorganic components in soilless cultivation and orchid substrates, and their low bulk density, high porosity, and strong drainage capacity help improve the root environment (Nuammee et al., 2024; Carrasco et al., 2025). Because a single inorganic substrate has weak nutrient-retention capacity and cannot fully meet the long-term growth and quality formation requirements of D. officinale, composite cultivation substrates are more commonly used in production practice. Composite substrates usually combine natural organic substrates, agricultural waste-based substrates, and inorganic substrates in specific proportions to balance water retention, aeration, structural stability, and nutrient supply. For example, pine bark combined with coconut coir, ceramsite, or perlite can simultaneously meet the needs of root aeration and moisture retention. Composite formulations containing bark, brick fragments, sphagnum moss, wood chips, and maize straw, after disinfection and fermentation, can stabilize substrate structure and reduce pathogen risk. During orchid acclimatization, mixed substrates containing brick fragments and charcoal together with water-retentive components such as sphagnum moss or fern fiber can improve root aeration and mechanical support, achieving survival rates of approximately 97~100% and supporting long-term growth (Nuammee et al., 2024). The advantage of composite substrates lies in their capacity for targeted design according to different growth stages, cultivation modes, and regional environments of D. officinale. Compared with single substrates, composite substrates can not only improve seedling survival and plant growth rate, but may also promote bioactive compound accumulation and commercial quality by improving rhizosphere moisture, oxygen, nutrients, and microbial conditions. Studies on Dendrobium production have shown that potting media composed of coconut-derived organic materials mixed with brick fragments, charcoal, and tile fragments can achieve better vegetative growth and flowering traits than coconut coir alone. This indicates that composite substrates have important application value by integrating organic nutrient supply with inorganic structural stability (Ashokkumar et al., 2023; Tt et al., 2024). In the future, under the concepts of resource recycling, precision cultivation, and quality-oriented production, the development of functional, standardized, and sustainable composite substrates will become an important pathway for promoting the high-quality development of the D. officinale industry. 3 Effects of Different Cultivation Substrates on the Growth of Dendrobium officinale 3.1 Effects on seedling survival rate and plant vigor Seedling survival rate is an important indicator for evaluating the cultivation effect of Dendrobium officinale and a direct basis for assessing substrate suitability. As D. officinale is an epiphytic plant, its seedling roots are relatively fragile and sensitive to changes in moisture, aeration, and environmental stability. Therefore, the water retention, aeration, structural stability, and disease-suppressive capacity of the substrate directly affect post-transplant survival. Existing studies have shown that sphagnum moss, pine bark, and their composite substrates can form a relatively stable moisture and air environment around the roots, reduce transplanting stress, and improve seedling survival. During the hardening stage, sphagnum moss can promote rapid root initiation, enhance tillering, and increase leaf thickness, stem diameter, plant height, leaf width, root length, root number, and biomass compared with bark treatment, making it more suitable for acclimatization and early transplantation of tissue-cultured plantlets. Different substrates not only affect seedling survival rate but also significantly influence plant vigor. Suitable substrates can improve the rhizosphere environment and enhance water and nutrient use efficiency, thereby promoting plant height growth, stem thickening, and leaf development. Studies have shown that a granular
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 174 substrate mainly composed of spent mushroom residues, Chinese herbal residues, and agricultural by-products such as chestnut shells, peanut shells, mulberry branches, corncobs, and wood chips can increase the transplant survival rate of D. officinale to more than 98%. After 1.5 years of cultivation, the average plant height reached approximately 78 cm and the stem diameter reached 7.5~8.2 mm, indicating good adaptability and growth vigor under field conditions. A cement-tile bed cultivation system using pine bark as the main substrate can also ensure a transplant survival rate of more than 98%, promote plant growth compared with traditional cultivation methods, advance flowering and stem formation, and increase yield per unit area. In addition, a 50:50 mixture of pine bark and fern fiber achieved a 100% survival rate 12 months after ex vitro transplantation and showed good performance in plant height, root number, fresh weight, and dry weight, suggesting that a rational combination of water retention and aeration is conducive to sustained seedling growth (Luan et al., 2021). The substrate requirements of D. officinale vary among different growth stages. The seedling stage relies more heavily on strong moisture retention and environmental stability, whereas during the rapid growth stage, the requirements for substrate aeration, drainage, and nutrient supply gradually increase. Wood-based substrate combinations such as bark-sawdust mixtures can also support high survival rates and favorable growth. Among them, an alder bark:fine sawdust ratio of 5:1 showed good performance in plant height, stem diameter, root number, and leaf number, and was considered a suitable cultivation substrate. Therefore, rationally selecting or adjusting substrate types according to different growth stages of D. officinale is an important measure for improving seedling survival, enhancing plant vigor, and achieving stable production. 3.2 Effects on root development and nutrient uptake Roots are important organs for water and mineral nutrient uptake in D. officinale, and their developmental status directly determines the subsequent growth potential of the plant. Cultivation substrates influence root morphogenesis and physiological activity by regulating rhizosphere moisture, oxygen, and nutrient supply. Substrate porosity, water-holding capacity, drainage, and nutrient status are key factors determining root development in D. officinale. Well-aerated substrates are conducive to root apical meristem activity and new root formation, whereas prolonged waterlogging or poor aeration can easily cause root hypoxia, inhibit root growth, and even induce root rot. During the hardening stage, sphagnum moss significantly increases root length, root number per cluster, and root biomass, indicating that a moist, fine-textured, and well-aerated medium facilitates rapid root proliferation and functional root formation in seedlings. Bark-based substrates and composite substrates supplemented with structural materials such as fern fiber, perlite, and ceramsite are beneficial for increasing root length, root number, and root activity. A pine bark-based mixed substrate combined with fern fiber promoted rooting under greenhouse conditions over 12 months, enabling plants to develop more roots, longer roots, and higher fresh weight than other tested substrates (Luan et al., 2021). Some nutrient solutions and granular substrate formulations also aim to rapidly promote root emergence from stems and improve transplant survival. Reported results indicate that the cultivation period for complete plant formation can be shortened to approximately 25 days, with a high field survival rate, suggesting that nutrient-rich, well-buffered, and structurally suitable substrates can significantly promote root initiation and growth. For D. officinale, which has well-developed aerial roots, maintaining an appropriate air-water ratio is essential for healthy root development. Substrates also serve as reservoirs and exchange interfaces for mineral nutrients and carbon sources. Widely targeted metabolomic studies have shown that pine bark, coconut coir, and their mixed substrates differ significantly in physicochemical properties, including water-holding capacity and nitrogen, phosphorus, and potassium contents, leading to marked changes in the stem metabolite profiles of D. officinale. This suggests that nutrient acquisition and metabolic status differ under different substrate conditions (Zuo et al., 2020). Ecophysiological studies have also found that total nitrogen, total phosphorus, pH, and available phosphorus in the soil are closely related to polysaccharide, total alkaloid, and flavonoid contents, and these parameters are all influenced by substrate selection in artificial cultivation systems (Yuan et al., 2020). In addition, mycorrhizal associations formed within or on the surface of substrates can enhance nutrient uptake. The growth-promoting
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 175 fungus MF23 can increase root dry weight, root length, and seedling height in D. officinale, and upregulate genes related to nitrate, ammonium, amino acid, and peptide transporters, thereby promoting nitrogen uptake and assimilation (Figure 2) (Shan et al., 2021). Other mycorrhizal fungi can also enhance carbon acquisition from substrates, improve photosynthetic efficiency, and increase seedling biomass and polysaccharide content. Figure 2 Putative nitrogen uptake and metabolism in the D. officinale-MF23 symbiosis (Adopted from Shan et al., 2021) Image caption: Black font represents the background subjects; red, blue, and gray font represent up-, down-, and undifferentiated-regulated genes or metabolites, respectively. White boxes represent enzymes (Adopted from Shan et al., 2021) 3.3 Effects on biomass accumulation and dry matter distribution Biomass accumulation is the result of the combined effects of photosynthesis, nutrient uptake, and material metabolism, and it is also an important indicator for evaluating substrate performance. Suitable substrates can provide stable moisture, oxygen, and nutrient conditions for D. officinale, promote the formation and transport of photosynthetic products, and thereby increase plant fresh weight and dry weight. Studies have shown that granular substrates rich in organic residues can produce an average yield of approximately 580 kg/mu in D. officinale, with a polysaccharide content of 42.5%, indicating that optimized substrates with high nutrient density are conducive to the synchronized accumulation of stem biomass and medicinal components. Pine bark seedbed cultivation can increase growth rate, advance flowering and stem formation by 1~3 years, and produce more than 250 kg/mu, suggesting that coarse, durable bark substrates can sustain high aboveground biomass accumulation over multiple years when combined with appropriate fertilization and management. Different cultivation substrates also affect the distribution of dry matter among roots, stems, and leaves. The main medicinal part of D. officinale is the fleshy stem; therefore, the extent of dry matter accumulation in the stem is closely related to medicinal material yield and quality. Under suitable substrate conditions, plants can maintain high photosynthetic efficiency and nutrient transport capacity, allowing more assimilates to be transported to and stored in the stems, thereby promoting stem thickening and improving medicinal yield. Container cultivation studies have shown that turf-bark substrates can significantly increase the fresh weight and dry matter content of tissue-cultured plantlets, while sphagnum moss substrates not only promote growth but also increase polysaccharide content. This suggests that different substrates may guide biomass allocation toward structural growth or toward storage and medicinal component accumulation, respectively. In addition, biomass accumulation is closely related to the formation of bioactive components. Sufficient dry matter accumulation not only provides a material basis for plant growth, but also supplies carbon sources and energy for the synthesis of polysaccharides, alkaloids, and other secondary metabolites. Mycorrhizal cultivation studies have shown that MF23 inoculation significantly increases root and stem dry weight, root length, and seedling height compared with axenic culture, and its promoting effect becomes stronger over time (Shan et al., 2021). Compared with non-mycorrhizal controls, ex vitro seedlings associated with mycorrhizal fungi have
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 176 greater increases in fresh and dry weight, taller plants, thicker stems, and more new roots and tillers, indicating that mycorrhizal symbiosis can coordinately increase total biomass and promote biomass allocation to the stems, which are harvested as medicinal materials. From a broader ecological perspective, stem, leaf, and total biomass of D. officinale vary significantly among different provenances and environmental conditions, indicating that substrate-related environmental factors and genetic conditions jointly drive patterns of dry matter distribution. Therefore, from the dual goals of yield and quality improvement, selecting suitable substrates and combining them with beneficial microbial regulation is an important approach for promoting biomass accumulation and optimizing dry matter distribution in D. officinale. 4 Effects of Different Cultivation Substrates on Quality Formation inDendrobium officinale 4.1 Effects on polysaccharide accumulation Polysaccharides are among the most important bioactive constituents of Dendrobium officinale and serve as a core indicator for evaluating its medicinal quality. In addition to possessing immunomodulatory, antioxidant, and metabolic regulatory activities, polysaccharides directly influence the medicinal value and market competitiveness of D. officinale. Previous studies have demonstrated that polysaccharide content is highly responsive to growth conditions. Cultivation mode, root-zone physicochemical environment, nutrient availability, and water status can all affect polysaccharide accumulation, and these factors are largely regulated by cultivation substrates (Yuan et al., 2020). Comparative studies conducted across different production regions and cultivation systems have shown that variations in light intensity, temperature, water availability, and nutrient conditions can lead to substantial differences in polysaccharide content, indicating that polysaccharide biosynthesis exhibits considerable environmental plasticity (He et al., 2022). Substrates with favorable water-holding capacity, aeration, and nutrient-buffering ability are generally more conducive to polysaccharide formation and accumulation. Pine bark, sphagnum moss, and their composite substrates provide a relatively stable rhizosphere environment, promoting photosynthate production, carbon accumulation, and carbohydrate metabolism, thereby enhancing polysaccharide content. Reviews have emphasized that appropriate artificial substrates and cultivation systems are among the most important agronomic strategies for increasing polysaccharide yield in modern D. officinale production systems (Chen et al., 2021). At present, epiphytic cultivation and wild-simulated cultivation have become major production approaches. These systems typically employ bark- or tree-based substrates and aim to produce green, organic medicinal materials with high polysaccharide content. Comparisons among cultivation sites and production techniques indicate that plants grown under more favorable microclimatic conditions and substrate-nutrient environments are more likely to meet or exceed the polysaccharide standards specified in the Chinese Pharmacopoeia, whereas lower compliance rates are often observed in environmentally less suitable regions (He et al., 2022). It should be noted that polysaccharide accumulation does not necessarily increase in parallel with plant growth. Instead, it is jointly influenced by genotype, cultivation age, cultivation mode, and substrate conditions. Multi-year metabolomic analyses have shown that carbohydrates and glycosides are the predominant metabolites in D. officinale, and the third cultivation year may represent the optimal harvest period based on carbohydrate accumulation patterns. In standardized cultivation systems, tetraploid breeding materials have exhibited nearly double the stem polysaccharide content of diploid plants, indicating that polysaccharide accumulation depends not only on substrate optimization but also on genetic improvement and harvest timing management (Pham et al., 2019). Therefore, cultivation practices should balance yield and quality by optimizing substrate structure, nutrient supply, and harvest age to achieve the coordinated enhancement of both polysaccharide content and biomass production. 4.2 Effects on dendrobine, flavonoids, and other bioactive constituents In addition to polysaccharides, dendrobine, flavonoids, phenolic compounds, bibenzyls, and phenolic glycosides are important functional constituents of D. officinale. Dendrobine and related alkaloids possess potential anti-inflammatory, neuroprotective, and immunomodulatory activities, whereas flavonoids and phenolic compounds are closely associated with antioxidant activity, free-radical scavenging, and stress defense. The
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 177 accumulation of these bioactive compounds is regulated not only by genetic background but also by cultivation environment and substrate conditions. By altering rhizosphere moisture, oxygen availability, nutrient supply, and the microecological environment, different substrates influence the allocation of resources between primary and secondary metabolism, thereby regulating the biosynthesis and accumulation of dendrobine, flavonoids, and related compounds. Widely targeted metabolomic analyses comparing D. officinale stems cultivated in pine bark, coconut coir, and a 1:1 mixture of the two substrates revealed that although the overall metabolite categories remained similar among treatments, significant differences occurred in metabolite abundance. Among the 529 detected metabolites, flavonoids exhibited the most pronounced variation, with most flavonoid compounds preferentially accumulating in plants grown on pure pine bark. KEGG enrichment analysis further demonstrated that flavonoid biosynthesis was the only pathway significantly affected by substrate-induced metabolic changes, indicating a direct relationship between substrate selection and flavonoid metabolic regulation (Figure 3) (Zuo et al., 2020). These findings suggest that bark-based substrates not only facilitate root attachment and vegetative growth but may also promote the accumulation of specific bioactive compounds through alterations in metabolic pathway activity. Figure 3 Score plot of principal component analysis (PCA) for D. officinale samples (Adopted from Zuo et al., 2020) Image caption: Planted in pine bark (PB), coconut coir (CC), pine bark: coconut coir 1:1 mix (PC), and quality control (QC) samples; PC1 represents the first principal component and PC2 represents the second principal component (Adopted from Zuo et al., 2020)
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 178 In addition to substrate comparison studies, investigations involving different production regions and cultivation systems have also demonstrated that low-molecular-weight bioactive compounds are highly sensitive to environmental conditions. Metabolomic analyses of wild-simulated cultivation systems and materials from different geographical origins have identified numerous differentially accumulated metabolites, with significant enrichment of flavonoid and flavonol biosynthesis pathways and substantial variation in flavonoid content among habitats (Lan et al., 2022; Luo et al., 2023). Integrated proteomic-metabolomic studies have further shown that phenylpropanoid and flavonoid biosynthesis pathways are key targets affected by environmental variation. Critical enzymes such as phenylalanine ammonia-lyase and chalcone synthase exhibit differential regulation among production regions. Significant regional differences have also been reported for dendrobine and related alkaloids, suggesting that cultivation conditions, including substrate properties and soil nutrient status, can influence alkaloid accumulation (Guan et al., 2025). Therefore, selecting substrates with appropriate physical structure, nutrient characteristics, and moderate ecological stimulation effects may facilitate the accumulation of flavonoids, alkaloids, and other bioactive compounds, thereby enhancing the medicinal quality of D. officinale. 4.3 Effects on comprehensive evaluation of medicinal and commercial quality Quality evaluation of D. officinale encompasses not only chemical indicators such as polysaccharides, alkaloids, and flavonoids, but also antioxidant capacity, morphological traits, stem quality, tissue texture, and commercial grading characteristics. High-quality D. officinale typically exhibits thick stems, uniform internodes, bright coloration, well-developed tissues, and elevated levels of bioactive constituents. Consequently, the dual effects of cultivation substrates on plant morphology and active constituent accumulation ultimately determine both medicinal and commercial quality. Previous studies have indicated that the medicinal quality of D. officinale is determined by a comprehensive profile of polysaccharides and various low-molecular-weight compounds, and is closely associated with functional activities such as antioxidant capacity (Chen et al., 2021; Xu et al., 2022; Wang et al., 2025; Yang et al., 2026). In medicinal quality assessment, reliance solely on polysaccharide content has certain limitations. Comparative studies involving materials from different regions and cultivation environments have demonstrated that high polysaccharide levels do not necessarily coincide with elevated concentrations of flavonoids, phenolic glycosides, or other low-molecular-weight compounds. In some cases, regions producing materials with high polysaccharide content have exhibited relatively low levels of certain small-molecule constituents (He et al., 2022). Metabolomic and bioactivity studies have shown that flavonoids and phenolic acids are major contributors to the antioxidant capacity of D. officinale, and strong correlations have been observed between specific flavonoid glycosides and antioxidant indicators (Luo et al., 2023). Therefore, substrates or cultivation environments that promote flavonoid accumulation, such as pine bark-based systems, may enhance certain biological functions even when polysaccharide content remains relatively unchanged (Zuo et al., 2020; Lan et al., 2022). From the perspectives of commercial quality and industrial application, substrate selection also influences stem thickness, fresh weight, uniformity, and processing suitability, thereby affecting commercial grading and market acceptance. Numerous studies have suggested that quality evaluation systems for D. officinale should incorporate representative low-molecular-weight biomarkers and biological activity indicators in addition to polysaccharides, because cultivation conditions—including substrate characteristics—can alter the balance among different classes of compounds, and such changes may not be directly reflected in appearance or yield (Chen et al., 2021; He et al., 2022). Regional comparisons under artificial shading cultivation have shown that D. officinale produced in southern cultivation regions generally contains higher levels of polysaccharides, flavonoids, and total polyphenols than material produced in newly established northern production areas, indicating that differences in regional environments and rhizosphere conditions may influence overall nutritional and medicinal value even under similar cultivation techniques. Therefore, future quality-oriented cultivation strategies should incorporate rational substrate selection and establish comprehensive evaluation systems that simultaneously consider polysaccharides, dendrobine, flavonoids, phenolic compounds, morphological traits, and commercial grade, thereby meeting the requirements of pharmacopoeial standards, functional food development, and market quality expectations.
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 179 5 Mechanisms by Which Cultivation Substrates Influence Growth and Quality of Dendrobium officinale 5.1 Regulatory effects of substrate physicochemical properties on the rhizosphere environment The physicochemical properties of cultivation substrates are fundamental factors influencing the growth and quality formation of Dendrobium officinale. These properties mainly include porosity, bulk density, water-holding capacity, aeration, pH, cation exchange capacity, and nutrient contents such as nitrogen, phosphorus, and potassium. As a typical epiphytic plant, D. officinale possesses roots that are highly sensitive to oxygen availability and fluctuations in water status. Therefore, substrates with good aeration and appropriate water retention can maintain normal root respiration, nutrient uptake, and metabolic activities, thereby creating a stable rhizosphere environment for plant growth. In contrast, substrates with poor aeration, excessive bulk density, or prolonged waterlogging may lead to root-zone hypoxia, suppress root activity, and even induce root rot, ultimately impairing plant growth and quality formation. Significant differences exist among substrates in terms of water retention, drainage capacity, and nutrient availability, and these variations further influence metabolic processes within the plant. Zuo et al. (2020) conducted a widely targeted metabolomic analysis of D. officinale stems cultivated in pine bark, coconut coir, and a 1:1 mixture of the two substrates. Their results showed substantial differences among substrates in water-holding capacity and nutrient contents, particularly nitrogen, phosphorus, and potassium, which were closely associated with distinct metabolite profiles in the plants. Although the overall categories of metabolites were similar among substrate treatments, considerable differences were observed in metabolite abundance. Multivariate analyses, including principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), clearly distinguished samples derived from different substrates, indicating that substrate physicochemical properties exert strong regulatory effects on plant metabolism (Zuo et al., 2020). Furthermore, studies comparing greenhouse cultivation, simulated-natural cultivation, and wild growth conditions demonstrated that soil pH, total nitrogen, total phosphorus, and available phosphorus are important environmental factors affecting polysaccharide, total alkaloid, and flavonoid contents in D. officinale, further highlighting the close relationship between root-zone chemical environments and medicinal quality (Yuan et al., 2020). The hydraulic characteristics of substrates also influence root-zone water-oxygen distribution and plant performance. Studies on coconut coir-and perlite-based soilless media have shown substantial differences in water retention curves, saturated hydraulic conductivity, pore-size distribution, and bulk density among substrates. These characteristics collectively determine the distribution of water and air within the confined root zone. Substrates possessing high total porosity, appropriate levels of plant-available water, and adequate aeration space generally create a low-stress rhizosphere environment that supports healthy growth in container cultivation systems (Gohardoust et al., 2020). Research on other horticultural crops has similarly demonstrated that combining organic materials such as coconut coir with inorganic components such as perlite and tuff can optimize water retention and aeration, thereby improving nutrient-use efficiency, plant growth, and yield (Tang et al., 2024). Therefore, for D. officinale, substrates capable of maintaining a balance among water retention, drainage, aeration, and nutrient buffering are more conducive to sustaining stable root-zone water-oxygen dynamics and nutrient supply, thereby promoting both growth and quality formation. 5.2 Effects of substrate microorganisms on nutrient uptake and metabolic activities In addition to physicochemical properties, microbial communities within cultivation substrates are important factors affecting the growth and quality formation of D. officinale. Cultivation substrates serve not only as physical supports for root attachment and growth but also as habitats for diverse microorganisms, including bacteria, fungi, and actinomycetes. These microorganisms participate in organic matter decomposition, nutrient cycling, rhizosphere metabolism, and plant stress regulation, thereby exerting substantial effects on root
Medicinal Plant Research 2026, Vol.16, No.3, 169-189 http://hortherbpublisher.com/index.php/mpr 180 development, nutrient acquisition, and metabolic activities. In orchids such as D. officinale, rhizosphere and endophytic microorganisms not only enhance the uptake of water and mineral nutrients but may also contribute to the biosynthesis of quality-related metabolites, including polysaccharides, alkaloids, and flavonoids. Studies of the D. officinale microbiome have provided important evidence for understanding substrate-microbe-plant interactions. Wang et al. (2022) conducted metagenomic analyses of D. officinale growing in nutrient-poor Danxia habitats and identified highly diverse microbial communities in both rhizosphere and endophytic compartments. These communities included plant growth-promoting rhizobacteria such as Massilia, Pseudomonas, Bradyrhizobium, Paenibacillus, and Streptomyces, as well as beneficial fungi including Tulasnella and Serendipita. Functional annotation revealed significant enrichment of pathways related to carbohydrate, amino acid, and energy metabolism, indicating that these microorganisms facilitate nutrient mobilization and transformation, thereby supporting plant survival and growth under low-fertility conditions (Wang et al., 2022). A review of rhizosphere microbiomes in Dendrobium species further suggested that plant growth-promoting bacteria and fungi can enhance nitrogen and phosphorus uptake, produce phytohormones such as indole-3-acetic acid and gibberellins, and suppress pathogens, collectively improving plant growth, stress tolerance, and quality (Sarsaiya et al., 2025). Different cultivation systems and root-zone conditions may also alter microbial community composition and their influence on metabolite production. Studies on Dendrobium denneanum cultivated under tree-mounted, rock-mounted, and pot cultivation systems showed that soil properties, particularly total phosphorus and pH, simultaneously affected root microbial communities and metabolite profiles. Correlation analyses revealed associations between specific microorganisms, including Occallatibacter and Clonostachys, and the pharmacologically active compound gigantol, suggesting that root-associated microorganisms participate in regulating secondary metabolite biosynthesis (Chen et al., 2023). Broader rhizosphere microbiome studies have likewise demonstrated that the rhizosphere represents a hotspot for nutrient cycling and root nutrition, with enrichment of genes involved in organic compound transformation, nitrogen fixation, and denitrification relative to bulk soil (Ling et al., 2022). In crops such as maize and pea, arbuscular mycorrhizal fungi and rhizobia have been shown to enhance phosphorus and nitrogen uptake, reshape rhizosphere bacterial communities, and improve yield and nutrient-use efficiency (Lu et al., 2023; Calderon and Dangi, 2024). Collectively, these findings suggest that substrate-associated microbiomes may be regarded as extensions of root function in D. officinale, influencing growth and medicinal quality through enhanced nutrient acquisition, improved stress resistance, and regulation of metabolic pathways. 5.3 Relationship between substrate-induced stress and secondary metabolite accumulation The formation of plant secondary metabolites is regulated not only by genetic factors but also by environmental conditions. Bioactive constituents of D. officinale, including polysaccharides, dendrobine, flavonoids, and phenolic compounds, are closely associated with plant responses to environmental stimuli. By altering water availability, aeration, salinity, nutrient balance, and rhizosphere microecological conditions, different cultivation substrates may impose varying degrees of physiological stress on plants, thereby influencing defense responses and the activation of secondary metabolic pathways. Moderate substrate-induced stress may stimulate defense mechanisms, redirecting carbon, nitrogen, and energy resources toward the biosynthesis of flavonoids, alkaloids, and other protective metabolites. However, excessive stress can inhibit photosynthesis and biomass accumulation, resulting in reduced growth and quality. Previous studies investigating salt, temperature, and osmotic stresses have provided valuable insights into the relationship between environmental stimuli and the accumulation of quality-related metabolites in D. officinale. Under treatment with 250 mmol/L NaCl, significant transcriptomic and metabolomic reprogramming occurred in leaves, including marked changes in phenylalanine metabolism, flavonoid biosynthesis, and α-linolenic acid metabolism. Genes involved in jasmonic acid biosynthesis were upregulated, accompanied by increased levels of flavonoids, carbohydrates, and alkaloids. These findings suggest that jasmonic acid may act as a signaling molecule promoting flavonoid biosynthesis, enabling plants to adapt to salt stress through enhanced secondary
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