Medicinal Plant Research 2025, Vol.15, No.3, 119-128 http://hortherbpublisher.com/index.php/mpr 123 4.3 Relationship between root development and seedling survival Robust root systems are closely related to a higher transplanting survival rate. In the tissue culture of A. roxburghii, the survival rate of plants with good root systems after domestication can reach 80%, highlighting the importance of root vitality in the process of soil formation (Zhang et al., 2025a). In addition, the enhanced root development demonstrated by the quadruple system further improved the transplanting survival rate, and subsequent growth performance (Huang et al., 2022). The coordinated development of roots, stems and leaves, is the key to ensuring the excellent traits of seedlings. Treatment measures (specific light schemes, hormone combinations, etc.), that can simultaneously promote the growth of roots and stems and leaves can cultivate more robust plants, which perform better in biomass accumulation and physiological functions, and have enhanced adaptability and stress resistance (Wang et al., 2018; Huang et al., 2022; Zhang et al., 2025a). 5 Measurement and Analysis of Antioxidant Capacity in A. roxburghii 5.1 Antioxidant enzyme activity assays Generally, the antioxidant capacity of A. roxburghii, is evaluated by detecting the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Studies have shown that, in both in vitro and in vivo experiments, the extracts and polysaccharides of A. roxburghii can increase the activities of SOD and CAT, and reduce the level of malondialdehyde (MDA), indicating a strong protective effect against oxidative stress (Zeng et al., 2016; 2017; Wang et al., 2020). For instance, pretreatment with ARPP80 polysaccharide can restore the levels of SOD and CAT in the liver and serum of mice, and its effect is comparable to that of standard antioxidant drugs (Zeng et al., 2016). Light quality and growth regulator treatment can also regulate the activities of these enzymes. Among them, blue light can increase the activities of SOD, POD and CAT in plant tissues (Ye et al., 2017; Wu et al., 2024). Comparative analysis reveals that, different extraction methods, dosages, and environmental conditions (such as light quality) can lead to differences in the activity of antioxidant enzymes. Medium and low doses of phenolic extracts can enhance the activities of SOD and glutathione peroxidase (GSH-Px), and reduce the MDA level in oxidative stress models, while high doses may have poor effects or even negative effects (Xu et al., 2017; Wang et al., 2020). 5.2 Non-enzymatic antioxidant compounds A. Roxburghii is rich in non-enzymatic antioxidant substances, mainly including phenols and flavonoids. Quantitative determinations (Folin-Ciocalteu method for total phenol determination, the NaNO2-Al (NO3)3-NaOH method for flavonoid determination, etc.) indicated that, the contents of total phenol and total flavonoids were the highest under the residue extract and specific light quality or hormone treatment (Xu et al., 2017; Xie et al., 2017; Ye et al., 2017). Quercetin, kaempferol and rutin are the main contributing compounds of antioxidant activity, and their contents increase under stress conditions or after exogenous application (Xie et al., 2017; Bin et al., 2022; Cui et al., 2023). The accumulation of secondary metabolites such as phenols, flavonoids and polysaccharides is correlated with the overall antioxidant capacity. These compounds can not only directly eliminate free radicals, but synergistically enhance the function of the enzymatic antioxidant system, improving the ability of plants to resist oxidative damage (Yang et al., 2017; Liu et al., 2020; Wu et al., 2021; Qiu et al., 2023). 5.3 Antioxidant capacity and stress tolerance Growth regulators that can enhance the activity of antioxidant enzymes and the accumulation of secondary metabolites, as well as environmental factors (such as light quality), can also improve the stress resistance of A. Roxburghii. For instance, exogenous quercetin treatment can enhance antioxidant capacity, and also increase the heat tolerance of plants. Meanwhile, polysaccharide and flavonoid extracts can effectively reduce oxidative damage in animal and cell models (Wang et al., 2020; Cui et al., 2023).
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