Plant Gene and Trait 2025, Vol.16, No.1, 39-46 http://genbreedpublisher.com/index.php/pgt 43 which play significant roles in anthocyanin synthesis. Xu et al. (2024) found that the transcription factors related to these enzyme genes contain many hormone-responsive cis-elements, indicating that hormones play a key role in regulating the expression of these metabolic pathway genes. 5.3 Molecular mechanisms of hormonal balance in growth and metabolism of Anoectochilus roxburghii Light can affect the hormone levels in plants, causing changes in anthocyanin content, and anthocyanin is one of the important secondary metabolites of Anoectochilus roxburghii. Further studies have also found that hormone balance is achieved through the interaction between endogenous hormones and some specific transcription factors, which regulate the expression of genes related to metabolism (Liu et al., 2015). This hormone regulatory mechanism is beneficial for Anoectochilus roxburghii to maintain a good growth state and metabolic efficiency when facing environmental changes. 6 Optimized Application of Hormone Types and Concentrations in Anoectochilus roxburghii Tissue Culture 6.1 Practical application cases of different hormone combinations in Anoectochilus roxburghii transplantation The combination of different hormones has been proven to effectively increase the survival rate of transplantation in the tissue culture of Anoectochilus roxburghii. Adding 6-BA, NAA and KT to the MS medium can well induce the formation of clustered buds, among which using stem segments as explants has the best effect. The study by Qie et al. (2021) also found that the incidence of buds was as high as 95.92% in the medium with 6-BA, NAA and ZT added, indicating that these hormones are useful for promoting the survival of transplanting. The selection of the right hormone combination is crucial for improving the transplantation success rate of Anoectochilus roxburghii (Jim, 2024). 6.2 Promotion of growth and metabolism by optimizing hormone concentrations Different concentrations of hormones (such as 6-BA, NAA and 2,4-D) can affect the induction and reproductive effects of the protocorm-like body and adventitious bud. Delfosse et al. (2020) found that in the medium containing 6-BA (2.0 mg/L), NAA (0.5 mg/L) and TDZ (0.2 mg/L), the proliferation rate of Anoectochilus roxburghii reached 23 times within 90 days. Delfosse et al. ’s research in 2015 demonstrated that the use of low concentrations of hormones can also induce thicker buds, promote the differentiation of stems and leaves, thereby helping to enhance the overall growth and metabolic efficiency of plants. 6.3 Research on synergistic effects of hormones, substrates, and environmental conditions The coordination among hormones, culture media and environmental conditions has a significant impact on the tissue culture effect of Anoectochilus roxburghii. The combination of 6-BA and 2,4-D performed best in callus induction, and the induction rates of rhizomes and young stems were higher than those of leaves and in vivo embryos. The light conditions can affect the degree of callus browning rates. The browning rate under long-term dark treatment is lower than that under alternating light and dark conditions (Holmstrup et al., 2010). When improving the efficiency of tissue culture, environmental factors such as hormones, substrates and light should all be taken into account (Zhang and Guo, 2009). 7 Case Studies: Application of Hormonal Optimization in Anoectochilus roxburghii Cultivation 7.1 Analysis of successful cases of hormonal treatments Appropriate hormone combination treatment can significantly improve the induction and proliferation effect of the callus tissue of Anoectochilus roxburghii. Izuddin et al. (2018) found that the combined use of hormones such as 6-benzylaminopine (6-BA), naphthylacetic acid (NAA), and zeatin (ZT) could effectively promote the formation and expansion of callus tissue. Phillips et al. (2020) believed that the most effective medium formula was to add 0.2 mg/L of 2,4-D, 0.9 mg/L of NAA, 1.0 mg/L of 6-BA and 0.25 mg/L of ZT to the MS medium. The induction rate of this combination on rhizomes and young stems was much higher than that on leaves and in vivo embryos. The combined treatment with 6-BA, NAA, ZT and 2,4-D can successfully induce protocorm-like body (PLBs), increase the proliferation and regeneration rates, and achieve very good results (Jiang, 2024).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==