水分胁迫下钙对甘蔗幼苗抗氧化酶活性的影响

笔者选取甘蔗福农95-1702为材料，结合钙离子螯合剂EGTA预处理，对水分胁迫下Ca2+与甘蔗幼苗抗氧化酶类活性的关系进行研究，探讨逆境信号转导第二信使Ca2+在甘蔗抗旱性中的作用。结果表明，1~3mmol/L的EGTA预处理对正常生长条件下甘蔗幼苗的相对生长率、可溶性蛋白含量及抗氧化酶活性均无显著影响。但30%PEG处理下，1~3mmol/L的EGTA预处理降低了甘蔗幼苗的相对生长量，加剧了可溶性蛋白含量的下降：在处理的24小时，处理1E+D（1mmol/LEGTA+30%PEG）及3E+D(3mmol/LEGTA+30%PEG)中的可溶性蛋白含量分别比处理D（30%PEG）降低了40.2%和54.3%。同时，EGTA预处理抑制了PEG胁迫下超氧化物歧化酶（SOD）和过氧化物酶（POD）活性的升高，加剧了过氧化氢酶（CAT）活性的降低：在处理的24小时，处理1E+D及3E+D中的SOD活性分别比处理D降低了26.5%和29.9%；而POD活性则比处理D分别降低了31.3%和23.2%；处理3E+D的CAT酶活性比处理D降低了27.2%。这些结果暗示Ca2+可能参与了水分胁迫下甘蔗幼苗抗氧化酶系统的调节，Ca2+信号和活性氧（ROS）所介导的信号转导途径存在交叉互作

Relationship between Calcium and the Activities of Antioxidant Enzymes in Sugarcane Seedlings under Water Stress

In this work,we investigated the relationship between calcium and the activities of antioxidant enzymes in sugarcane(Saccharum officinarum L) variety(Funong 95-1702) seedlings under water stress.It was found that there were no significant changes in the relative growth rate,the content of soluble protein and the activities of antioxidant enzymes by the pretreatment of EGTA of 1~3 mmol/L in sugarcane seedlings under normal condition.But the relative growth rate and the content of soluble protein were both decreased by the pretreatment of EGTA of 1~3 mmol/L under water stress: after treating of 24h,the content of soluble protein in seedlings under treatments of 1E D(1mmol/L EGTA 30%PEG) and 3E D(3mmol/L EGTA 30%PEG) were decreased by 40.2% and 54.3% respectively compared to that in seedlings under treatment of 30%PEG.In addition,the pretreatment of EGTA inhibited the PEG-induced increases in activities of superroxide dismutase(SOD) and peroxidase(POD),and aggravated the PEG-in duced decrease in the activity of catalase(CAT).It demonstrated that Ca2 was involved in regulating the activities of antioxidant enzymes under water stress and there might be a crosstalk between signal transduction pathways mediated by Ca2 and reactive oxygen species(ROS).