钙抑制剂对机械损伤胁迫下合作杨叶片活性氧代谢的影响

以1年生合作杨扦插苗为材料,研究了叶面喷施Ca2+通道阻断剂氯化镧(LaCl3)和Ca2+螯合剂EGTA预处理对机械损伤胁迫下合作杨叶片抗氧化酶活性、过氧化氢(H2O2)和丙二醛(MDA)含量以及氧自由基(O2?-)产生速率的影响.结果显示,与对照相比,机械损伤胁迫下合作杨叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)等抗氧化酶活性均显著升高,活性氧水平和MDA含量显著增加;外源喷施EGTA和LaCl3降低了机械损伤胁迫下叶片SOD、POD、CAT和APX活性,减缓了O2?-产生速率,H2O2含量和MDA含量显著下降;且EGTA的抑制作用比LaCl3更强.研究表明,机械损伤胁迫诱导的活性氧代谢需要Ca2+的参与,Ca2+和活性氧在植物防御信号传递过程中密切相关;伤害诱导胞外Ca2+内流是胞内Ca2+浓度增加的重要来源.

Effects of Calcium Inhibitors on Reactive Oxygen Species Metabolism in Poplar Leaves under Mechanical Damage Stress

With one year old poplar(Populus simonii×P.pyramidalis cv.’Opera 8277’) as materials,the effects of Ca2+ channel blockers LaCl3 and Ca2+ chelator EGTA on antioxidant enzymes activities,H2O2 and MDA contents,and O-·2 producing rate in poplar leaves under mechanical damage stress were studied.The results showed that the activities of SOD,POD,CAT and APX were significantly higher than those of control;the contents of H2O2 and MDA and producing rate of O-·2 were obviously increased in poplar leaves treated by mechanical damage.Exogenous EGTA and LaCl3 application on the leaf remarkably reduced the activities of SOD,POD,CAT and APX,slowed down the producing rate of O-·2,the contents of H2O2 and MDA were decreased;And the inhibition of EGTA was stronger than that of LaCl3.The results suggested that the metabolism of active oxygen species induced by mechanical damage stress need the participation of Ca2+.Ca2+ and active oxygen species were closely related in plant defense signal transmission;extracellular Ca2+ influx induced by damage was an important source of the increasing of intracellular Ca2+ concentration.The damage induced Ca2+ flowed into cells and increased Ca2+ concentration in cells.