To investigate the effect of calcium and ABA on photosynthesis and the activities of antioxidant enzymes in cucumber seedlings under drought stress, the cucumber was used as the expe-riment materials, normal nutrient solution culture was considered as the control, and PEG-6000 application in the nutrient solution simulated the drought stress. There were five different treatments which were spraying water, ABA, CaCl2+ABA, LaCl3(calcium channel inhibitor)+ABA and EGTA (calcium ion chelating agent)+ABA under drought stress. The results showed that drought stress inhibited the growth of cucumber seedlings, and reduced the activities of antioxidant enzymes, nitrate reductase, net photosynthetic rate and fluorescence parameters of the cucumber seedlings leaves. The application of ABA reduced the inhibition of activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX), photosynthesis (Pn, gs) and the fluorescence parameters (Fv'/Fm', qP and ETR), and decreased the damage of drought stress on plant. Spraying CaCl2+ABAsignificantly promoted the positive effect of ABA, while EGTA+ABA and LaCl3 +ABA didn't show the promoting effect.
为探讨在干旱胁迫下钙与脱落酸对黄瓜幼苗光合作用及相关酶活性的影响,以黄瓜为试材,正常营养液栽培为对照,利用PEG-6000(聚乙二醇)营养液添加模拟干旱胁迫,设干旱胁迫条件下幼苗叶片喷施清水、脱落酸(ABA)、CaCl2+ABA、LaCl3(钙离子通道抑制剂)+ABA及EGTA(钙离子螯合剂)+ABA等5个处理.结果表明: 干旱胁迫抑制了黄瓜幼苗的营养生长、降低了幼苗叶片的抗氧化酶和硝酸还原酶活性,以及光合作用和荧光参数等,通过叶面喷施ABA减小了幼苗叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)活性,以及光合作用(Pn、gs)和荧光参数(Fv′/Fm′、qP和ETR)的下降幅度,有效缓解了干旱胁迫对植株造成的伤害;喷施CaCl2+ABA显著促进了ABA的这种正向缓解作用,而喷施LaCl3+ABA和EGTA+ABA都没有表现出促进作用.
Keywords: abscisic acid; calcium; cucumber seedling; enzyme activity; photosynthesis.