高温胁迫下4种杜鹃叶片的生理生化响应

Physiological and Biochemical Responses of Leaves of Four Rhododendron Cultivars under Heat Stress

为了研究高温对4个杜鹃花品种耐热性生理机制的影响,本研究以‘凤冠’(FG)‘、御代之荣’(YDZR)、‘红阳’(HY)、‘幻境’(HJ)4个杜鹃(Rhododendron simsii Planch.)品种为试材,于人工气候箱进行环境控制试验。以25℃/17℃为对照(CK),设置30℃/22℃,35℃/27℃,40℃/32℃共3个高温处理,分别在处理5 d后测定杜鹃叶片的各项生理指标,以期探究高温对不同杜鹃品种耐热性影响的生理机制。结果表明,(1)杜鹃叶片的丙二醛(MDA)、脯氨酸(Pro)、还原型谷胱甘肽(GSH)、氧化性谷胱甘肽(GSSG)含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性总体随胁迫程度加深呈先升高后降低的变化规律,且在35℃处理5 d后达到峰值;(2)杜鹃叶片的可溶性蛋白(SP)、抗坏血酸(AsA)含量随温度升高呈显著下降趋势‘,凤冠’和‘幻境’显著低于‘御代之荣’和‘红阳’;(3)‘御代之荣’和‘红阳’的Pro、GSH、GSSG含量、SOD、CAT、POD、APX、GR活性均高于‘凤冠’和‘幻境’,而MDA含量比‘凤冠’和‘幻境’低。综合分析,随高温胁迫程度不断加深,杜鹃叶片体内活性氧(ROS)大量积累,抗氧化酶活性和渗透调节物质增加,杜鹃叶片的生理代谢发生明显变化,品种‘御代之荣’和‘红阳’的耐热性要优于‘凤冠’和‘幻境’。

In order to study the effect of high temperature on the physiological mechanism of heat tolerance of four Rhododendron cultivars,’Fengguan’(FG),’Yudaizhirong’(YDZR),’Hongyang’(HY),’Huanjing’(HJ),three artificial environmental control experiments and one basis experiment were designed in artificial climate chamber.The control experiments were set at 30℃/22℃,35℃/27℃,40℃/32℃,respectively,and the basis experiment was set at 25℃/17℃.After 5 days of treatment,the physiological indexes of Rhododendron leaves was measured.The results showed as follows,(1)Contents of malondialdehyde(MDA),proline(Pro),reduced glutathione(GSH),oxidized glutathione(GSSG)and activities of superoxide diamutase(SOD),catalase(CAT),superoxide dismutase(POD),ascorbate peroxidase(APX),glutathione reductase(GR)of Rhododendron leaves increased first and then decreased with the deepening of stress,and reached the peak after 5 days of treatment at 35℃;(2)The contents of soluble protein(SP)and ascorbicacid(AsA)in Rhododendron leaves decreased significantly with the increase of temperature,and the contents of FG and HJ were significantly lower than those of YDZR and HY;(3)The contents of Pro,GSH,GSSG and activities of SOD,CAT,POD,APX,GR of YDZR and HY were higher than those of FG and HY,but the content of MDA was lower than that of FG and HY.In conclusion,with the deepening of high temperature stress,a large amount of reactive oxygen species(ROS)accumulated in leaves of Rhododendron,antioxidant enzyme activities and osmoregulation substances increased.Physiological metabolism of Rhododendron leaves changed significantly.The heat tolerance of YDZR and HY was better than that of FG and HJ.