Medicinal Plant Research 2025, Vol.15, No.4, 161-168 http://hortherbpublisher.com/index.php/mpr 162 the need to blend basic research with practical methodology and providing paths toward developing stress-tolerant seedlings and environmentally friendly industry operations. 2 Research Status of Stress Tolerance in S. mukorossi Seedlings 2.1 Physiological and biochemical responses related to stress tolerance Sapindus mukorossi seedlings have a range of physiological and biochemical mechanisms to survive environmental stress conditions such as drought and heavy metal exposure. An increase in the osmotic regulators proline and soluble protein content under water stress conditions maintains cellular water balance. Indicators of membrane stability and stress damage, i.e., malondialdehyde (MDA) and relative electrical conductivity (REC), also rise as water stress increases. The activity of antioxidant enzymes—peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT)—is enhanced in the beginning to resist oxidative damage but decreases in extreme or prolonged stress. The adaptation is controlled to maintain homeostasis and drought tolerance, making S. mukorossi a candidate for afforestation in semi-arid regions. Furthermore, leaf water physiological status is maintained by collaboration between osmoregulation substances and protective enzymes 2.2 Advances and limitations in current research on stress tolerance Recent studies have enhanced knowledge on S. mukorossi stress responses, particularly towards drought and heavy metal tolerance. Drought stress not only induces physiological defense but also compounds allelopathic effects and can contribute to habitat expansion. S. mukorossi has shown significant tolerance to lead (Pb) and phytoremediation potential with seedlings sustaining growth and Pb accumulation in roots and leaves and no visible toxicity on long durations. Fertilization management has also been marked as critical, with optimal levels of nitrogen, phosphorus, and potassium significantly increasing soil fertility, leaf physiological traits, and production. Overfertilization, however, has detrimental effects on soil health as well as on plant physiology. Studies are still lagging in many aspects: the majority of work addresses drought and heavy metals, fewer address low temperature, salt stress, and biotic stresses. The molecular mechanism for these reactions remains unknown, and field experiments of long term are scarce (Sahito et al., 2023; Zhong et al., 2023). 2.3 Comparative insights from studies on other woody or economic forest seedlings Comparative studies show that mechanisms of stress tolerance in S. mukorossi, e.g., osmotic adjustment, antioxidant enzyme activity, and allelopathy, are similar to those in other woody and economic tree species. For instance, moderate fertilization enhances physiological characteristics and yield in S. mukorossi and other crops such as blueberries and mung beans, whereas high levels of fertilization may deteriorate development and soil health. Even the tolerance and remediation of heavy metal-contaminated soils occur to other tree species that are fast-growing in nature, which are involved in urban forestry and ecosystem restoration. Convergence shows that insight from general forestry science can be utilized in designing more resilient strategies in the cultivation of S. mukorossi (Liu et al., 2024a). 3 Molecular Basis of Stress Tolerance in S. mukorossi Seedlings 3.1 Signal perception and transduction mechanisms Recent genomics and transcriptomics in Sapindus mukorossi have identified a number of genes for perception and transduction of stress signals. Candidate genes such as SmPP2C (abscisic acid signaling), SmAHP (cytokinin signaling), and SmLRR-RKs (leucine-rich repeat receptor kinases) suggest that the pathways of hormone signaling, calcium signaling, and ROS (reactive oxygen species) signaling pathways play crucial roles to mediate abiotic stresses (Xue et al., 2022). These kinds of mechanisms are consistent with evidence in other crop and woody plants, where hormone and ROS signaling plays a critical role in stress acclimation (Wang et al., 2021). 3.2 Roles of key transcription factor families in stress regulation Genome-scale analyses have shown the presence and selection of functionally diverse transcription factor families in S. mukorossi, including WRKY (e.g., SmWRKY6, SmWRKY26, SmWRKY33), bHLH (e.g., SmbHLH1), and others. These transcription factors regulate downstream stress-responsive gene expression, enabling the modulation of drought, salinity, and other stress physiological and biochemical reactions (Xue et al., 2022).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==