油菜素内酯对秦岭高山杜鹃耐热性的影响

Effects of Brassinolide on Tolerance of Rhododendron lapponicum in Qinling to Heat Stress

以野生高山杜鹃幼苗为试材,研究不同质量浓度[0(对照)、0.05、0.10、0.50、1.00、1.50 mg/L]油菜素内酯(BR)对高山杜鹃热害指数及生理生化指标的影响。结果表明:在高温胁迫下,随着BR质量浓度的增加,超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性及脯氨酸、可溶性蛋白含量均呈现先升后降的趋势,且BR质量浓度在0.5 mg/L时脯氨酸含量、可溶性蛋白含量最高分别为32.8μg/g、2.5 mg/g,SOD、POD、CAT活性最高分别为89.6、84.5、25.5 U/g;MDA含量呈现先降后升的趋势,且BR质量浓度在0.5 mg/L时效果最为明显,MDA含量在高温胁迫72 h比对照组降低40.49%;不同质量浓度BR均能降低热害指数,缓解高温对高山杜鹃幼苗的伤害。BR质量浓度为0.50 mg/L时对高温胁迫下高山杜鹃各项生理生化特征有较好的缓解作用,可减轻高温对杜鹃的热伤害,提高其耐热性。

Wild seedlings of Rhododendron lapponicum was taken as materials to study the effect of differ-ent concentrations of brassinolide [ 0 （ CK） ,0. 05,0. 10,0. 50,1.00,1.50 mg/L ] on their physiological indexes related to thermo-tolerance under high temperature stress. The results showed that, under high temperature conditions, the activities of SOD, POD, CAT and the contents of proline and soluble protein all increased first and then decreased with the increase of brassinolide concentration. When the concentration of brassinolide was 0.50 mg/L,the contents of proline and soluble protein were the highest ,which were 32.8 ｜xg/g and 2.5 mg/g,and the activities of SOD,POD and CAT were the highest,which were 89.6, 84. 5 ,25. 5 U/g. The MDA content decreased first and then increased. When the concentration of brassin-olide was 0. 50 mg/L,the MDA content was lowest,which was decreased by 40. 49% compared with the control at 72 hours. The different concentration of brassinolide could reduce damage index and relieve the damage of high temperature to the seedlings. When the concentration of brassinolide was 0.50 mg/L, the physiological and biochemical characteristics of Rhododendron lapponicum could be relieved under the high temperature stress, which could reduce the heat damage and improve the heat tolerance of Rhododen-dron lapponicum.