Medicinal Plant Research 2025, Vol.15, No.4, 151-160 http://hortherbpublisher.com/index.php/mpr 156 exogenous polyamines), help maintain membrane stability and reduce the accumulation of malondialdehyde (MDA). MDA is an important marker of lipid peroxidation and cell damage (Sun et al., 2023; Zhong et al., 2025). So, these physiological parameters can serve as reliable indicators of root health and stress resistance. 5.3 Stress tolerance indicators Antioxidant enzyme activities - including superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) - are key physiological indicators, reflecting the stress resistance of root systems. Under conditions, like high temperature, salt stress or water shortage, the enhanced activities of SOD and CAT indicate that the ability of the root system to eliminate reactive oxygen species (ROS) is improved, enhancing the stress resistance of the roots (Zhang et al., 2024; Jiang et al., 2025). Exogenous treatments, such as the application of spermidine or rare earth elements, can further enhance the activities of these enzymes and promote root adaptation (Xu et al., 2016; Sun et al., 2023). The increase in proline and soluble sugar content, is a reliable indicator for measuring the osmotic regulation, and stress adaptability of the root system of A. roxburghii. These compounds accumulate under environmental stress and can maintain cell turgor pressure, protect cell structure, and promote overall stress resistance and recovery (Zhang et al., 2020a; Sun et al., 2023; Zhang et al., 2024). In addition, the interaction between light quality and microorganisms, also can affect the accumulation of these osmotic protective substances (Wang et al., 2018; Ye et al., 2020). 6 Case Studies 6.1 Application of growth regulators in Anoectochilus roxburghii The use of growth regulators, like indole-3-butyric acid (IBA) and 6-benzylaminopine (6-BA), can enhance the root regeneration of A. roxburghii. Zhang et al. (2025b) compared different hormone combinations, medium types and light quality conditions, to establish an efficient bud proliferation and rooting system. The experimental results show that, 1 mg/L BA + 0.05 mg/L NAA is the best hormone treatment combination, increasing the number of buds and the induction rate. In terms of medium selection, the B5 formula is more effective than MS and its diluted formula. In the photolysis treatment, the proliferation efficiency, was the highest under red light conditions, and both the number of buds and the induction rate reached the optimal level. During the rooting stage, the combination of MS medium and 1 mg/L IBA + 1 mg/L NAA performed the best, with significant improvements in the number of roots, survival rate and growth height. Eventually, the survival rate of domestication and transplantation reached 80% (Figure 2). Exogenous application of plant hormones and rare earth elements, like La(NO3)3, Ce(NO3)3), can enhance the activities of antioxidant enzymes (SOD, CAT, POD), reduce the content of malondialdehyde (MDA), and improve root vitality and stress resistance during regeneration (Xu et al., 2016). Besides, treatment with strigolactone can alleviate low phosphorus stress, and improve plant adaptability by reducing oxidative damage and promoting root elongation (Zhong et al., 2025). 6.2 Effects of substrates on Anoectochilus roxburghii root recovery The composition and aeration of the substrate, have a significant impact on the root regeneration of A. roxburghii. Studies have shown that, the substrate ratio of peat soil: river sand: peanut shell = 4∶2∶2, can achieve the highest survival rate, the longest root length and the largest root diameter, indicating that a well-aerated substrate, is conducive to promoting the vigorous development and regeneration of the root system (Zhu et al., 2019). Hydroponic systems with cotton layers or coconut coir substrates, can also promote the growth of stems, leaves and roots, and increase biomass and the content of lycoposide, further demonstrating the importance of substrate structure and aeration for optimal root recovery (Luan et al., 2025). Nutrient-rich substrates can increase the survival rate, and enhance the vitality of the root system as well, which is manifested as an increase in plant height, fresh weight and root count (Zhu et al., 2019; Luan et al., 2025). Substrate selection, also affects the accumulation of secondary metabolites, like flavonoids and polyphenols, which are closely related to plant health and stress resistance.
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