夜间低温胁迫下钙对番茄幼苗根系活力及活性氧代谢的调控作用

研究夜间低温胁迫下(25℃/6℃,昼/夜)钙、钙离子螯合剂(EGTA)和钙离子通道抑制剂(LaCl3)对番茄幼苗根系中根系活力、可溶性蛋白含量、膜质过氧化程度及活性氧(ROS)代谢的调控作用。结果表明,夜间低温胁迫(蒸馏水灌根)显著降低番茄幼苗根系活力、可溶性蛋白含量,增加根系MDA、H2O2含量及O2-.产生速率,抑制SOD、CAT和POD活性;45 mmol.L-1CaCl2灌根显著提高夜间低温胁迫下番茄幼苗根系活力、可溶性蛋白含量及SOD、CAT和POD活性,降低根系MDA含量、H2O2含量及O2-.产生速率;EGTA、LaCl3灌根加剧夜间低温胁迫导致的番茄根系活力的降低及活性氧的增加。表明夜间低温胁迫对番茄幼苗地下部根系的活性氧代谢产生显著的影响,而Ca2+通过提高保护酶活性、降低膜质过氧化水平来提高番茄植株根系的低温耐受性,进一步防止植株低温伤害。

Effects of Calcium on Root Activity and Metabolism of Reactive Oxygen Species of Tomato Seedlings under Low Night Temperature Stress

In order to investigate the regulating mechanism of calcium on tomato seedlings under low night temperature stress,tomato roots were used to study the changes of root activity,soluble protein content,the content of MDA and metabolism of reactive oxygen species(ROS) after the tomato seedlings were treated by calcium or inhibitor under low night temperature of 6 ℃(25 ℃/6 ℃,day/night).The results showed that root pouring of H2O significantly decrease root activity and the content of soluble protein,increase the contents of MDA,H2O2 and production rate of O2-·,inhibit activities of SOD,CAT and POD of tomato seedlings under low night temperature;Ca2+could significantly increase root activity and the content of soluble protein,decrease contents of MDA,H2O2 and production rate of O2-·,enhance activities of SOD,CAT and POD.On the contrary,EGTA and LaCl3 could further decrease root activity and enhance membrane lipid peroxidation.These results indicated that low night temperature has significant effects on ROS metabolism in roots,and calcium might increase low temperature tolerance of tomato and prevent low night temperature damage to the plant by enhancing the activities of some antioxidant enzymes and reducing ROS levels.