外源水杨酸对2个杜鹃花品种抗旱性的影响

摘要

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 chlorophyl1,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 H2 O2,and protect the activity of SOD and POD.Therefore,it can reduce damage caused by drought stress and improve the drought resistance of Rhododendron.%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.