中文摘要：

采用营养液栽培系统，以黄瓜品种‘中农8号’为材料，研究了Ca^2＋对根际低氧胁迫下黄瓜幼苗体内超氧阴离子（O2^-↑·）、过氧化氢（H2O2）、丙二醛（MDA）含量和超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）、谷胱苷肽还原酶（GR）活性的影响。结果表明：低氧胁迫下黄瓜体内活性氧含量和保护酶活性均高于对照；低氧缺钙处理的活性氧含量最高，而保护酶活性却较低；营养液Ca^2＋浓度提高到8mmol／L后，显著降低了低氧胁迫下黄瓜幼苗体内MDA、H2O2含量和O2^-↑·产生速率，提高了SOD、POD、CAT、APX、GR活性，说明Ca^2＋可减少低氧胁迫下黄瓜幼苗体内活性氧的产生，提高抗氧化酶的活性、降低膜脂过氧化水平，减缓低氧胁迫对植株的伤害，增强黄瓜幼苗对低氧逆境的适应性。

英文摘要：

By means of a system of nutrient solution culture,a cucumber variety, ‘Zhongnong 8’ was used to study the superoxide radical （O2^-↑·） and hydrogen peroxide （H2O2） contents and POD,CAT, APX and GR activities in cucumber seedlings under low rhizosphere oxygen stress. It was shown that the reactive oxygen species content and antioxidative enzyme activities in cucumber seedlings under low rhizosphere oxygen stress were higher than those in control seedlings;in the treatment with low oxygen and calcium deficiency,the reactive oxygen species content appeared the highest and the antioxidative enzyme activities appeared lower; under low oxygen stress cucumber seedlings significantly decreased their MDA and H2O2 contents and superoxide radical-producing rate and raised their SOD,POD,CAT,APX and GR activities after the Ca^2＋ concentration was raised to 8 mmol/L in the nutrient solution,and this indicated that Ca^2＋ could reduce reactive oxygen species production and raise the activities of anti-oxidative enzymes, decrease the membrane lipid peroxidation in cucumber seedlings, and alleviate the damage of low oxygen stress to the plants and enhance the adaptability of cucumber seedlings to low-oxygen environments.