干旱及冻融胁迫对黑麦草抗氧化酶活性和脯氨酸质量比的影响

以冬牧70黑麦草为材料, 用聚乙二醇（PEG 6000）模拟干旱胁迫, 设置5%（D1),10%(D2),15%(D3)三种不同程度干旱（轻度、 中度、 重度）以及对照组（CK）, 温度为10,5,0,-5,0,5,10 ℃, 研究冻融及干旱胁迫对幼苗中抗氧化酶活性和脯氨酸质量比的影响. 结果表明： 单一干旱胁迫下黑麦草幼苗中超氧化物歧化酶（SOD）、 抗氧化物酶 （POD）活性和脯氨酸质量比均 增加; 冻融和复合胁迫下幼苗中SOD活性呈先升高后显著下降趋势, POD活性和脯氨酸质量比呈先升高后缓慢下降趋势, 在-5 ℃出现峰值, 与其他温度下的数值存在显著性差异（P<0.05）; 胁迫伤害下整体呈复合胁迫>单干旱胁迫>单冻融胁迫的趋势, 冻融胁迫下的伤害程度为重度干旱+冻融>轻度干旱+冻融>单一冻融>中度干旱+冻融, 复合胁迫对植物伤害出现叠加效应, 适当的干旱处理可缓解冻融对幼苗的生理损害. 因此植物通过提高抗氧化酶活性和渗透调节物质, 可缓解其遇到胁迫时的伤害.

Effects of Drought and Freeze Thaw Stress on Antioxidant Enzymes Activities and Mass Ratio of Proline of Secale cereal L.#br#

Using the Secale cereal L. (rye) as material, polyethylene glycol (PEG 6000) was used to simulate drought stress, and three kinds of drought (mild, moderate and severe) with 5%（D1),10%(D2) and 15%(D3) and control group (CK) were set up, and the temperatures were 10,5,0,-5,0,5,10 ℃, we studied the effects of freeze thaw and drought stress on the antioxidant enzyme activities and mass ratio of proline in seedlings. The results show that the superoxide dismutase (SOD) and peroxidase (POD) activities and mass ratio of proline of rye seedlings were increased under single drought stress. The SOD activity increased first and then decreased significantly, while the POD activity and mass ratio of proline  increased first and then decreased slowly under the combined stress. The enzyme activities and mass ratio of proline of different treatment groups reach the maximum at -5 ℃, and there is significant difference with other temperatures (P<0.05). The injured degree of seedlings caused by different stresses is combined stress>single drought stress>single freeze thaw stress. The injured degree is severe drought+freeze-thaw>mild drought+freeze-thaw>single freeze-thaw>moderate drought+freeze-thaw under the combined stress treatments. The combined stress has a superimposed effect on plant damage, and a proper drought treatment can alleviate the physiological damage of freeze thaw to the seedlings. Therefore, plants can alleviate the damage by improving antioxidant enzyme activity and osmotic adjustment substances under freeze thaw and drought stress.