外源水杨酸对盐胁迫下巴西蕉生理的影响

香蕉是世界进出口贸易中具有重要经济价值的水果,也是非洲国家的粮食作物。盐害是影响香蕉产量和品质的重要因子之一。巴西蕉是我国华南地区的主栽品种。水杨酸在植物生理和代谢中扮演重要角色。盐胁迫下,外源水杨酸处理巴西蕉（Musa AAA Cavendish var. Brazil）幼苗的生理指标的变化未见报道。本研究通过叶面喷施0、0.5、1.0、2.0 mmol/L外源水杨酸,测定70 mmol/L NaCl胁迫下的巴西蕉幼苗叶片相对含水量、叶绿素含量、脯氨酸含量等生理指标的变化。结果表明,盐胁迫下巴西蕉幼苗的叶片相对含水量和叶绿素含量与对照相比显著下降,而脯氨酸含量、可溶性糖含量、可溶性蛋白含量以及丙二醛含量与对照相比均显著上升。施加0.5、1.0 mmol/L水杨酸处理与盐胁迫相比提高叶片相对含水量和叶绿素含量,提高叶片脯氨酸、可溶性糖和可溶性蛋白的含量,并且降低叶片丙二醛含量,而2.0 mmol/L 水杨酸处理的叶片相对含水量、脯氨酸含量、可溶性糖和可溶性蛋白含量与盐胁迫处理的差异不显著。因此,施加较低浓度的水杨酸（0.5、1.0 mmol/L）可在一定程度上缓解盐胁迫现象,但是高浓度水杨酸（2.0 mmol/L）缓解效果不明显,其中以1.0 mmol/L水杨酸处理效果最好。

Effects of Extraneous Salicylic Acid on Physiological Index of Brazil Banana Seedling under NaCl Stress

Banana (Musa spp.) is one of the most important economic fruits in the world and staple food in African. Salinity stress is a major factor that affects banana fruit production and quality. Brazil banana seedling (M. AAA Cavendish var. Brazil) is a major banana cultivar in South China. The plant phenolic salicylic acid (SA) plays a regulatory role in plant physiology and metabolism. Effects of extraneous SA on physiological index of Brazil banana seedling under NaCl stress is still unknown. In this paper, we focused on the need for analyzing the effect of physiological properties of Brazil banana seedling by means of spraying exogenous concentration (0.5, 1.0, 2.0, mmol/L) SA under 70 mol/L of NaCl salt stress, the effect of physiological indexes including relative water content (RWC), and proline content of leaves, were studied. The result indicated that under salt stress the relative water content on leaves and total chlorophyll content of the seedling decreased significantly, the content of prolinet, soluble sugars, soluble proteint and malondialdehyde (MDA) on leaves increased significantly. After further treatment with SA 0.5, 1.0 mmol/L, compared to only dealt with NaCl, the relative water content on leaves, the content of total chlorophyll, proline, soluble sugars and soluble proteins of the seedling increased significantly, while the content of MDA decreased. However, after further treatment with SA 2.0 mmol/L, compared to only dealt with NaCl, the relative water content on leaves, the content of proline, soluble sugars and soluble proteins had no significant difference. The symptom of salinity stress could be alleviated by the treatment of exogenous salicylic acid of adequate concentration (0.5, 1.0 mmol/L), with the optimum concentration of 1.0 mmol/L. However, high concentration of exogenous salicylic acid mitigation effect is not obvious.