黄腐酸钾提高水稻秧苗耐盐性的作用途径分析OA北大核心CSTPCD

[Objective]Salt stress is one of the important environmental factors limiting the yield and quality of crops,including rice.Developing risk cultivation techniques that enhance salt tolerance in rice is essential for ensuring food security in China.[Methods]In this study,Nipponbare was selected and subjected to salt stress at the seedling stage.Potassium fulvic acid(PFA)was exogenously sprayed onto rice seedling plants,with distilled water used as a control.The first fully expanded leaves were sampled to determine physiological parameters,including dry biomass,photosynthesis,carbohydrates contents,energy metabolism,Na+/K+ratio,and antioxidant enzyme activities during salt stress.[Results]Under salt stress,the dry biomass and plant height of rice seedlings treated with PFA were significantly higher than those treated with distilled water.Compared to the control,the relative electrolyte leakage,hydrogen peroxide(H2O2),and malondialdehyde(MDA)contents in the PFA-treated group were significantly lower than those in the water-treated group,indicating a stronger antioxidant capacity in the former.After salt stress treatment,the decrease in leaf chlorophyll content,actual photochemical quantum efficiency,relative electron transport rate,and net photosynthetic rate were lower in the PFA-treated group than in the water-treated group.There was no obvious difference in the contents of carbohydrates in leaves between these two treatments;PFA effectively reduced the inhibition of energy metabolism by salt stress.It was found that the PFA-treated seedling plants exhibited significantly lower decreases in leaf ATP content,energy charge,and ATPase activity compared to the water-treated group under salt stress.Correspondingly,the increment in potassium ion concentration and decrement in sodium ion concentration in the PFA-treated group were higher than those in the water-treated group.[Conclusion]Potassium fulvic acid can improve leaf photosynthesis,promote ATP production and utilization,enhance antioxidant capacity,maintain a higher potassium ion concentration,and lower reactive oxygen species and sodium ion concentrations under salt stress.This,in turn,mitigates damage to rice seedling plants caused by salt stress,providing technical and theoretical support for the development of salt tolerance cultivation techniques and chemical regulators for rice seedlings.