高温胁迫下海南杜鹃和白花杜鹃的生理响应比较分析

Physiological Responses Comparison of Rhododendron hainanense and Rhododendron mucronatum(Blume) G. Don under High Temperature Stress

为阐明海南杜鹃响应高温胁迫的生理机理,分别以狭域种海南杜鹃和和广域种白花杜鹃的两年生扦插苗为材料,对不同温度条件下(25℃,35℃和40℃)两种杜鹃花叶片中可溶性蛋白质、可溶性糖、丙二醛(MDA)、过氧化氢(H_2O_2)、脯氨酸(Pro)含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性进行了测试分析。研究结果表明:(1)海南杜鹃和白花杜鹃的MDA、H_2O_2、Pro、可溶性糖含量、APX、CAT活性均随胁迫温度的升高而增加;(2)海南杜鹃的Pro、可溶性糖含量、SOD和APX活性高于白花杜鹃;海南杜鹃的蛋白质、H_2O_2含量比白花杜鹃低;白花杜鹃的MDA含量和CAT活性随胁迫温度的增加,增幅逐渐增大,40℃时高于海南杜鹃。通过运用隶属函数法对海南地区两种常绿杜鹃品种耐热性综合评价发现,海南杜鹃具有较强的耐热性,优于白花杜鹃。本研究不仅验证了海南杜鹃在抗热方面具有很强的可塑性,还为海南杜鹃引种驯化提供了理论指导。

To investigate the physiological mechanism of R.hainanense responding to high temperature stress,2-year-old cuttings of Rhododendron hainanense and Rhododendron mucronatum（Blume） G.Don were used as experimental material.The levels of soluble protein,soluble sugar,malondialdehyde（MDA） hydrogen peroxide（H2O2）,proline（Pro） and activities of superoxide dismutase（SOD）,catalase（CAT） and ascorbate peroxidase（APX） in leaves were determined and analyzed under different temperature（25℃,35℃ and 40℃） treatments.The results showed that contents of MDA,H2O2,Pro,soluble protein and activities of APX,CAT of Rhododendron hainanense and Rhododendron mucronatum（Blume） G.Don increased with the going up of temperature;compared with Rhododendron mucronatum（Blume） G.Don,the contents of soluble protein,soluble sugar and activities of SOD and APX of R.hainanense were higher.The content of protein and H2O2 in R.mucronatum was higher than that in R.hainanense.The content of MDA and CAT activity of R.mucronatum increased gradually with the increase of stress temperature,which were higher than that of R.hainanense at 40℃.By using the subordinate function values analysis,the heat tolerance of two evergreen azaleas varieties in Hainan province was studied.It was found that the R.mucronatum had stronger heat tolerance which was better than that of R.mucronatum.Our researches not only verify that R.hainanense could suffer high temperature stress,but also might provide theoretical guidance for introduction and domestication of R.hainanense.