外源水杨酸对盐胁迫下白榆生理特性的影响

目的]以白榆幼苗为材料,研究不同浓度水杨酸(SA)的喷施对盐胁迫下白榆生理代谢的影响。[方法]以1年生白榆品种‘白洼一号’幼苗为材料,在0、50、100和150 mmol·L~(-1)Na Cl浓度下,喷施不同浓度SA(0、0.5、1.0、2.0 mmol·L~(-1)),处理30 d后对白榆水分生理、膜脂过氧化、光合色素含量和光合气体交换参数进行测定。[结果]表明:(1)盐胁迫下,外源SA可以显著提高白榆叶片相对含水量、可溶性糖含量,并降低丙二醛含量,但对电解质渗透率影响不显著。(2)0.5和2.0 mmol·L~(-1)SA会显著提高50和100 mmol·L~(-1)Na Cl胁迫下白榆叶片的光合色素含量,1.0 mmol·L~(-1)SA对各盐浓度下光合色素含量改善作用均不明显。(3)2.0 mmol·L~(-1)SA的添加提高了盐胁迫下白榆光合气体交换参数,1.0 mmol·L~(-1)SA明显降低了50 mmol·L~(-1)盐浓度下白榆叶片的净光合速率和气孔导度。[结论]适宜浓度的SA能改善白榆的生理参数,隶属函数法综合评价表明:0.5和2.0 mmol·L~(-1)SA对盐胁迫下白榆生理参数的改善作用较明显。

The Effect of Exogenous Salicylic Acid on the Physiological Characteristics of Ulmus pumila Plantlet under NaCl Stress

[Objective] To study the effect of spraying Salicylic acid (SA) with different concentration on the physiological metabolism of Ulmus pumila tissue-cultured plantlets under salt stress.[Method] One-year-old U. pumila "Baiwa NO.1" plantlets were selected as materials and the effect of spraying different concentrations of SA (0, 0.5, 1.0, 2.0 mmol·L^-1) on the water physiology, membrane lipid peroxidation, photosynthetic pigment content and photosynthetic gas exchange parameters were studied under 0, 50, 100 and 150 mmol·L^-1 NaCl treatments.[Result] (1) Exogenous SA improved the relative water content and soluble sugar content in leaves significantly, and decreased the MDA content, but it had no significant effects on the electrolyte leakage. (2) 0.5 and 2.0 mmol·L^-1 SA improved the chlorophyll a, chlorophyll b, carotenoid and chlorophyll a+b contents in the leaves of U. pumila under 50 and 100 mmol·L^-1 NaCl stress. And the effect of 1.0 mmol·L^-1 SA on the chlorophyll content under each NaCl concentration was not significant. (3) The net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO₂ concentration (Ci) and transpiration rate (Tr) increased significantly with the addition of 2.0 mmol·L^-1 SA under NaCl stress. The addition of 1.0 mmol·L^-1 SA decreased Pn and Gs significantly under each NaCl concentration.[Conclusion] Appropriate SA concentration can alleviate the physiological parameters of U. pumila under salt stress. The results of comprehensive evaluation using the subordinate function method show that 0.5 and 2.0 mmol·L^-1 are the optimal concentration of SA.