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作 者 ：王秀红, 王秀峰, 杨凤娟, 魏珉, 史庆华, 焦娟, 刘全兴

期 刊 ：植物营养与肥料学报 2010年 16卷 4期 页码：1020-1026

关键词：精胺；NO-3胁迫；黄瓜幼苗；抗氧化酶；光合特性；

Keywords:spermine, NO-3stress, cucumberseedlings, antioxidantenzymes, photosyntheticcharacteristics,

摘 要 ：采用营养液培养方法，研究了添加不同浓度的精胺（Spm）对NO^-₃胁迫下黄瓜幼苗生长、叶片抗氧化酶活性及光合作用的影响。结果表明，140 mmol/L NO^-₃胁迫下，外加1 mmol/L Spm, 10 d后，黄瓜幼苗叶片超氧化物歧化酶（SOD）、 过氧化氢酶（CAT）、 过氧化物酶（POD)、抗坏血酸过氧化物酶（APX）活性显著增加，电解质渗漏率和丙二醛（MDA）含量显著降低; 气孔导度（Gs）、胞间CO₂浓度（Ci）和净光合速率（Pn）显著升高，气孔限制值（Ls）显著降低。说明1 mmol/L Spm处理能增强黄瓜幼苗对活性氧的清除能力，降低膜脂过氧化程度; 降低气孔关闭，改善叶片的气体交换，幼苗生长势增加，对高浓度NO^-₃胁迫的抗性增强。当Spm浓度高达1.5～2 mmol/L时，与1 mmol/L Spm相比，SOD、POD、APX、CAT活性均开始降低，电解质渗漏率和MDA含量增加，Gs、Ci和Pn显著降低，黄瓜幼苗生长受到抑制。可见，外加一定浓度的Spm可通过提高抗氧化酶活性、降低膜脂过氧化程度及改善光合作用来缓解NO^-₃胁迫对黄瓜幼苗的影响。

Abstract:In this study, cucumber seedlings were cultivated in nutrient solution with different concentrations of spermine（Spm）(0.5, 1, 1.5 and 2 mmol/L). The effects of exogenous Spm on growth of cucumber seedlings, activities of antioxidant enzymes and photosynthesis in cucumber leaves under NO^-₃ stress were investigated. The results show that activities of superoxidase(SOD), peroxidase(POD), catalase(CAT)and ascorbic acid peroxidase(APX)are significantly increased in the treatment of 1 mmol/L Spm for 10 d under 140 mmol/L NO^-₃ stress, and stomatal conductance(Gs), intercellular CO₂ concentration(Ci)and net photosynthetic rate(Pn)in leaves are significantly enhanced, while electrolytic leakage(EL), the accumulation of malondialdehyde(MDA)and stomatal limitation value(Ls)in cucumber seedlings are significantly decreased. These findings suggest exogenous Spm could enhance the capacity of scavenging active oxygen species and improve photosynthesis, protect cucumber seedlings from the peroxidation of membrane lipids, promote the growth and increase resistance to high concentration of NO^-₃ stress. After the cucumber seedlings growing in the 1.5-2 mmol/L Spm for 10 d, compared to growing in the 1 mmol/L Spm, activities of SOD, POD, APX and CAT, Gs, Ci and Pn are decreased under the 140 mmol/L NO^-₃ stress, while MDA level and electrolytic leakage are increased, resulting in injury of cucumber seedlings. These results indicate that the effect of exogenous Spm is dependant on the concentration of Spm. Excessive Spm treatment would decrease the resistance to NO^-₃ stress.

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