高温强光胁迫下水杨酸对多花黄精生理及光合特性的影响

[目的]本文旨在分析水杨酸（SA）对高温强光胁迫下多花黄精生理及光合特性的影响，探讨SA缓解多花黄精高温强光胁迫伤害的可行性。[方法]以遮阴处理的盆栽多花黄精为材料，叶面喷施0.5、1.0、1.5和2.0 mmol？L-1 SA后，撤掉遮阳网，然后进行高温强光胁迫处理，测定并分析胁迫处理期间及25℃遮阴恢复24 h后多花黄精叶片活性氧水平、渗透调节物质含量、抗氧化酶活性、光合及叶绿素荧光指标的变化。[结果]叶面喷施SA可促进多花黄精叶片脯氨酸和可溶性蛋白的积累，提高超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性，降低O2？-产生速率和H2O2含量，使丙二醛（MDA）含量和相对电导率显著下降，增强多花黄精抵御高温强光胁迫伤害的能力。同时，SA还能提高Fv/Fm、φPSⅡ和qP，降低NPQ，并能促进气孔开放和CO2转运，使多花黄精能够在逆境胁迫下维持较高的光学活性和净光合速率，但过高SA浓度则会加重多花黄精胁迫伤害。[结论]0.5~1.5 mmol？L-1 SA处理均能提高多花黄精抗逆性，尤其以1.0 mmol？L-1 SA的处理效果最佳。
[Objectives]The effects of salicylic acid(SA) on physiological and photosynthetic characteristics of Polygonatum cyrtonema Hua were studied,in order to reveal the feasibility that SA had a potential to alleviate the stress damages.[Methods]The plants were subjected to high temperature and strong light after a foliar application of SA,with concentrations of 0.5,1.0,1.5 and 2.0 mmol？L-1. The levels of reactive oxygen species(ROS),osmotic adjustment substances contents,antioxidant enzyme activities,changes of photosynthetic and chlorophyll fluorescence indexes were determined during the stress and recover(25℃,shading for 24 h) periods.[Results]The results showed that the accumulation of proline and soluble proteins in leaves was enhanced by foliar application of SA. As well,the activities of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) increased,and O2？- production rate and H2O2 content,malondialdehyde(MDA) content and relative electrolytic leakage decreased. The above results indicated that the ability of P.cyrtonema resisting high temperature and strong light stress was improved by foliar application of SA. Furthermore,optical activity and net photosynthetic rate of P.cyrtonema exposed to environmental stress were kept in high level since the Fv/Fm,φPSⅡ and qP increased,NPQ decreased,stomatal opening and CO2 was enhanced. However,stress damages caused to P.cyrtonema increased when higher levels of SA were applied.[Conclusions]Stress resistance was enhanced at concentrations of 0.5-1.0 mmol？L-1 SA,particularly 1.0 mmol？L-1