低温胁迫对高山杜鹃生理特性影响的研究

Effect of Low Temperature Stress on Physiological Characteristics of Rhododendron lapponicum

以秦岭野生高山杜鹃幼苗为试验材料,研究了不同温度下(0、5、10、25℃,其中25℃为对照)高山杜鹃叶片的相对电导率、游离脯氨酸、可溶性蛋白、丙二醛(MDA)含量,以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性。结果表明:低温胁迫会对高山杜鹃产生一定的伤害,在高山杜鹃幼苗中,10℃和5℃为轻微的低温逆境,0℃时低温胁迫生理伤害较为严重;在0、5、10℃下高山杜鹃的相对电导率与对照相比增加幅度分别为90.11%、49.79%和27.07%,差异达到显著水平;0℃处理下的MDA含量与对照相比增加幅度为88.12%,差异显著;可溶性蛋白含量显著上升,5℃和0℃处理下分别比对照增长了84.40%和89.43%;游离脯氨酸含量的变化不明显;SOD活性随时间延长呈现出先上升后降低再上升的变化规律,在0℃下变化最大,与对照相比增加幅度为84.87%;而POD和CAT活性也在0℃时达到最大,分别比对照提高了18.58%和85.47%。说明高山杜鹃在0℃低温条件下生长受到严重影响。

In order to investigate the effect of low temperature stress on the physiological characteristics of Rhododendron lapponicum,the author studied the relative conductivity,the content of free proline,soluble protein and malondialdehyde（MDA）,and the activity of superoxide dismutase（SOD）,peroxidase（POD） and catalase（CAT） in leaves of wild Qinling R.lapponicum seedlings at different low temperatures（0,5 and 10 ℃）.The results showed that low temperature（0 ～ 10 ℃,especially 0 ℃）stress could produce a certain harm to the seedlings of R.lapponicum.In comparison with the control（25 ℃）,the leaf relative conductivity of R.lapponicum seedlings at 0 ℃,5 ℃ and 10 ℃ was significantly increased by 90.11%,49.79% and 27.07%,respectively; the MDA content at 0 ℃ was significantly increased by 88.12%; the soluble protein content at 5 ℃ and 0 ℃ was significantly enhanced by 84.40% and 89.43%,separately.The changes in free proline content at various temperatures were not obvious.The SOD activity increased first,then decreased,and increased again along with the time extension,and it was the highest under 0 ℃ stress,being 84.87% higher than that in the control.The activity of POD and CAT was also the highest under 0 ℃stress,respectively being 18.58% and 85.47% higher than that in the control.The above results indicated that 0 ℃ stress had serious influences on the growth of R.lapponicum seedlings.