沙木蓼幼苗在不同盐度胁迫下的生理适应机制OA

To investigate the physiological response and adaptation mechanism of Atraphaxis bracteata under salt stress conditions,this study focused on A.bracteata seedlings and established five salt stress concentration gradients:0(CK),50(T1),100(T2),150(T3),and 200 mmol·L-1(T4).The effects of different salt stresses on gas exchange parameters,chlorophyll fluorescence parameters,antioxidant enzyme activity,osmotic substances,non-structural carbohydrates,and other indicators of A.bracteata seedlings were determined.Through correlation and principal component analyses,the physiological responses and adaptation mechanisms of A.bracteata seedlings under salt stress conditions were revealed.The results showed that with an increase in salt stress intensity,stomatal conductance,photosynthetic rate,and transpiration rate all showed a decreasing trend,whereas photosystem PSⅡ showed no significant change.The malondialdehyde,proline,soluble sugar,and starch contents all showed an overall upward trend,with antioxidant enzyme activity showing a trend of initial increase followed by a decrease.From these findings,it is considered that A.bracteata growth was inhibited to varying degrees,but seedlings can cope with the damage caused by salt stress by increasing the content of osmoregulatory substances and enhancing antioxidant enzyme activity.According to the PCA ranking,it can be concluded that the roots of A.bracteata seedlings are more severely affected by salt stress.These results provide a basis for studying the physiological response mechanism of A.bracteata under salt stress conditions and provide a theoretical foundation for breeding salt-tolerant afforestation varieties of A.bracteata.