外源水杨酸对2个杜鹃花品种抗旱性的影响

选择2个抗旱性较差的杜鹃花品种‘蓝茵’（Rhododendron‘Lan Yin’）和‘宁波红’（Rhododendron‘Ningbo Hong’）为试验材料，在不同浓度的水杨酸作用下，观察叶片形态并测定各项生理指标，判断其对杜鹃花抗旱性的影响。结果表明，施用不同浓度水杨酸后，‘宁波红’在水杨酸浓度为0.3、0.5 mmol·L^-1受旱害较轻，‘蓝茵’在水杨酸浓度为0.3、0.5 mmol·L^-1及0.7 mmol·L^-1受旱害较轻。适当浓度的水杨酸能提高杜鹃花叶片的总含水量、自由水含量和束缚水含量，保持较低的自由水/束缚水，能促进其叶绿素的合成，提高细胞内的可溶性糖、可溶性蛋白和脯氨酸等细胞渗透调节物质的浓度，防止细胞膜受损，抑制过氧化氢及丙二醛的积累，保护超氧化物歧化酶、过氧化物酶活性，从而减轻干旱胁迫对杜鹃花的伤害，提高杜鹃花的抗旱性。

Effects of Exogenous Salicylic Acid on Drought-resistance of Two Rhododendron Cultivars

Two Rhododendron cultivars which had poor drought resistance: Rh.‘Lan Yin’ and Rh.‘Ningbo Hong’ were selected as test materials.Based on the observation of the external morphology and the determination of physiological indexes,effects of exogenous ealicylic acid on drought-resistance of Rhododendron were evaluated.The results showed that after applying different concentrations of salicylic acid,degree of drought damage decreased in Rh.‘Ningbo Hong’ with the concentrations of 0.3,0.5 mmol·L^-1 and Rh.‘Lan Yin’ with 0.3,0.5 and 0.7 mmol·L^-1.The suitable concentrations of salicylic acid could improve free water content,leaf bound water content and total water content of Rhododendron,keep lower free water/bound water,promote the syntheses of chlorophyll,increase soluble sugar,soluble protein and proline in cells such as cell infiltration through concentration regulating substances,prevent the membrane damage and the accumulation of MDA and H_²O₂,and protect the activity of SOD and POD.Therefore,it can reduce damage caused by drought stress and improve the drought resistance of Rhododendron.