Zhang Zijie, Jin Huiying, Hong Kun, Fang Shengzuo
National Key Laboratory for the Development and Utilization of Forest Food Resources, Nanjing Forestry University, No. 159 Longpan Road, Xuanwu District, Nanjing, Jiangsu 210037, China.
College of Forestry and Grassland, Nanjing Forestry University, No. 159 Longpan Road, Xuanwu District, Nanjing, Jiangsu 210037, China.
Tree Physiol. 2025 Jun 2;45(6). doi: 10.1093/treephys/tpaf061.
Soil salinity is a major constraint limiting plant growth globally. Cyclocarya paliurus (Batal.) Iljinsk, a valuable tree species, exhibits limited tolerance to salinity, hindering its cultivation in saline soils. This study investigates the effects of salicylic acid (SA) and brassinolide (BR) applications on improving salt tolerance in C. paliurus using physiological, cytological and molecular approaches. Results showed that the application of SA or BR significantly alleviated salt-induced growth inhibition and oxidative stress in C. paliurus, but the alleviating effects varied in their application doses. The applications of 0.5 mM SA or 1.0 mg L-1 BR enhanced seedling height by 89.7-97.4% and photosynthetic rate by 106.3-146.9% whereas reducing salt injury index by 36.0-38.0%, which is mainly via regulating the antioxidant enzyme activities, secondary metabolite accumulation and gene expressions associated with these processes. Visualization staining of H2O2, O2•- and cell viability also revealed that applications of 0.5 mM SA or 1.0 mg L-1 BR reduced the distributions of H2O2 and O2•- in leaves and invigorated cell viability under salt stress. Based on the analysis of reactive oxygen species metabolism and flavonoid biosynthesis pathways, we infer that the SA or BR applications could alleviate the salt-stress in C. paliurus mainly via regulating reactive oxygen species scavenging and the expression of genes related to antioxidant enzymes and secondary metabolite biosynthesis pathways. These findings suggest that proper exogenous applications of either SA or BR hold promise for improving the salt tolerance of C. paliurus.
土壤盐渍化是限制全球植物生长的主要因素。青钱柳（Cyclocarya paliurus (Batal.) Iljinsk）是一种珍贵树种，但其耐盐性有限，这阻碍了它在盐渍土壤中的种植。本研究采用生理、细胞学和分子学方法，探究了水杨酸（SA）和油菜素内酯（BR）处理对提高青钱柳耐盐性的影响。结果表明，SA或BR处理显著缓解了盐胁迫对青钱柳生长的抑制作用和氧化应激，但缓解效果因施用剂量而异。0.5 mM SA或1.0 mg L-1 BR处理使幼苗株高增加了89.7-97.4%，光合速率提高了106.3-146.9%，同时盐害指数降低了36.0-38.0%，这主要是通过调节抗氧化酶活性、次生代谢产物积累以及与这些过程相关的基因表达来实现的。H2O2、O2•-的可视化染色及细胞活力检测结果还表明，0.5 mM SA或1.0 mg L-1 BR处理减少了盐胁迫下叶片中H2O2和O2•-的分布，并增强了细胞活力。基于对活性氧代谢和类黄酮生物合成途径的分析，我们推测SA或BR处理主要通过调节活性氧清除以及与抗氧化酶和次生代谢产物生物合成途径相关的基因表达来缓解青钱柳的盐胁迫。这些研究结果表明，适当外源施用SA或BR有望提高青钱柳的耐盐性。
