Effects of exogenous salicylic acid on growth and physiological characteristics of lettuce seedlings under salt stress
[Objective]To study the alleviate effect of salicylic acid(SA)on lettuce under saline stress and to provide a theoretical and technical basis for improving saline lettuce cultivation.[Method]No restric-tion of NaCl and no spraying of NaCl as control 1(CK1)and 200 mmol/L NaCl as control 2(CK2).Five SA treatments of foliar spray 0.1,0.3,0.6,1.2,2.4 mmol/L were set up to dynamically measure the growth and physiological related indexes of lettuce.[Result]Compared with the CK1 treatment,the CK2 treatment inhibited the growth of lettuce seedlings,reduced the accumulation of biomass and increased the content of soluble protein,soluble sugar and proline.Compared with CK2 treatment,foliar application of salicylic acid(0.6 mmol/L)at appropriate concentrations could reduce the inhibition of lettuce biomass accumulation in lettuce,promote the accumulation of soluble protein,soluble sugar and proline,and improve photosynthesis.Soluble sugar,soluble protein,net photosynthetic rate Pn,stomatic conductance Gs and transpiration rate Tr were increased by 37.5%,57.1%,74.4%,88.9%and 52.3%,respectively,while dV/dto(QA reduction ratio)was decreased by 22.5%.[Conclusion]Foliar application of SA alleviates growth inhibition of let-tuce plants under saline stress,increases soluble protein,soluble sugar and proline,reduces MDA and rela-tive conductivity,and increases photosynthetic capacity of lettuce leaves under saline pressure.
万方数据
维普
