林业科学2025，Vol.61Issue(5)：108-119,12.DOI:10.11707/j.1001-7488.LYKX20240047
纳米氧化锌提高秋茄幼苗抗寒性的生理机制
Physiological Mechanisms of ZnO NPs in Enhancing Cold Resistance of Kandelia obovata Seedlings
摘要
Abstract
[Objective]With the mangrove plant Kandelia obovata as the test material,this study investigated the mechanism by which nano zinc oxide(ZnO NPs)enhances the cold resistance of K.obovata seedlings,providing crucial technical support for the safe overwintering of mangroves on the northern margin or in higher latitudes.[Method]K.obovata seedlings were pre-treated with foliar spraying method with varying concentrations of ZnO NPs to determine the optimal application concentration.Seedlings were then sprayed with optimal concentration of ZnO NPs twice daily in the morning and evening for 3 days,followed by exposure to low-temperature stress at 8℃(day)/-3 ℃(night)for 3 days.Physiological indices such as photosynthetic rate,antioxidant enzyme activity,and melatonin(MEL)synthesis pathway were measured.[Result]The leaf net photosynthetic rate(Pn)and melatonin(MEL)content of seedlings initially increased and then decreased with increasing ZnO NP concentration,with 200 mg·L-1being the optimal concentration under low-temperature stress.Low-temperature stress significantly decreased endogenous MEL and nitric oxide(NO)contents and increased contents of superoxide anion(O2(·))and hydrogen peroxide(H2O2),thereby inhibiting photosynthesis.Spraying treatment with 200 mg·L-1 ZnO NPs on leaves was able to effectively increase the activities of N-acetylserotonin methyltransferase(ASMT)and tryptophan decarboxylase(TDC)in the MEL synthesis pathway of K.obovata seedlings under low temperature stress,and promote the production of various intermediate products(tryptamine,5-hydroxytryptamine,and 5-methoxytryptamine)in the synthesis process of melatonin from tryptophan.Additionally,ZnO NPs not only effectively increased antioxidant enzyme activities,reduced O2(·) and H2O2 contents,but also activated nitrate reductase(NR)activity by H2O2 in the leaves under low temperature stress,promoting NO2-production,and ultimately improving photosynthesis,which is closely related to the melatonin synthesis pathway.[Conclusion]ZnO NPs enhances the cold resistance of K.obovata seedlings by regulating the MEL/ROS/reactive nitrogen species(RNS)redox network under low-temperature stress.ZnO NPs may induce the tryptophan/tryptamine/5-hydroxytryptamine/5-methoxytryptamine/melatonin synthesis pathway in K.obovata seedlings under low-temperature stress,influencing the redox network formed by melatonin,ROS,and RNS.关键词
纳米氧化锌/低温胁迫/红树林/褪黑素合成途径/活性氧/活性氮/光合作用Key words
ZnO NPs/low temperature stress/mangroves/melatonin synthesis pathway/ROS/RNS/photosynthesis分类
农业科技引用本文复制引用
殷雅欣,陈思意,李军建,单巧博,郑春芳..纳米氧化锌提高秋茄幼苗抗寒性的生理机制[J].林业科学,2025,61(5):108-119,12.基金项目
国家自然科学基金项目(32071503)和温州市科技计划项目(S20220011). （32071503）
