水杨酸对盐胁迫下沙打旺幼苗生长的影响

Effects of salicylic acid on growth of Astragalus adsurgens seedlings under salt stress

水杨酸（salicylic acid,SA）作为一种植物激素,不仅参与植物生长和发育等过程,而且还能诱导植物的抗逆性。为研究外源水杨酸对盐胁迫下沙打旺幼苗生长的影响,以沙打旺幼苗为材料,采用200mmol/L NaCl并添加不同浓度SA（0.2,0.4,0.6,0.8,1.0mmol/L）的处理方法,通过测定沙打旺生长及生理指标,以确定外源SA对沙打旺幼苗生长的影响。结果表明,与单纯盐胁迫相比,一定浓度的SA（0.4-0.8mmol/L）能提高盐胁迫下沙打旺叶片可溶性蛋白含量,0.6和0.8mmol/L SA处理分别增加了51.9%和42.6%;增强盐胁迫下沙打旺叶片超氧化物歧化酶（SOD）活性,0.4和0.6mmol/L SA处理分别提高了1.58和1.68倍;降低叶片质膜透性,0.4,0.6和0.8mmol/L SA处理,叶片相对电导率依次降低了19.2%,26.6%和18.1%;提高盐胁迫下沙打旺的光合能力,0.4和0.6mmol/L SA处理,净光合速率分别增加了1.21和1.43倍;使株高和干重增加。其中,0.6mmol/L SA处理效果最为明显。表明外源SA能够在一定程度上促进盐胁迫下沙打旺幼苗的生长。

Salicylic acid （SA）has emerged as a plant hormone involved in the processes of growth and develop-ment,and induced resistance to various abiotic stresses in plants.Studies of the effects of exogenous SA on the growth of Astragalus adsurgens under salt stress will uncover the underlying mechanisms of stress relief. Seedlings of A.adsurgens were treated with 200 mmol/L NaCl and different concentrations of SA （0.2,0.4, 0.6,0.8 ＆ 1.0 mmol/L）;growth and physiological indexes were subsequently determined.The results showed that,compared with NaCl treatment without SA,exogenous SA ranging from 0.4 to 0.8 mmol/L in-creased soluble protein content and the activity of superoxide dismutase （SOD）in leaves of A.adsurgens .Sol-uble protein content increased by 51.9% and 42.6% respectively under 0.6 and 0.8 mmol/L exogenous SA treatments and the activity of SOD increased significantly by 1.58 and 1.68 times under 0.4 and 0.6 mmol/L SA concentrations.Leaf membrane permeability was reduced by SA.SA at 0.4,0.6 and 0.8 mmol/L reduced leaf conductivity by 19.2%,26.6% and 18.1% respectively.The photosynthetic capacity of A.adsurgens was also enhanced by exogenous SA treatment.For example,the net photosynthetic rate increased by 1.21 and 1.43 times under 0.4 and 0.6 mmol/L SA treatment.All SA treatments resulted in increased plant height and dry weight in A.adsurgens seedlings.The optimal level of exogenous SA was 0.6 mmol/L.These results in-dicated that the growth of A.adsurgens under salt stress was enhanced by exogenous SA.