亚精胺预处理对黄瓜幼苗抗冷性的影响

 以两叶一心的黄瓜幼苗为试材，喷施不同浓度的亚精胺（Spd）后再进行5℃低温胁迫4 d，研究了Spd对黄瓜幼苗生长、生理和生化特性的影响，以弄清Spd增强黄瓜抗冷性的效果及其生理机制。结果表明，0.50 mmol·L^-1的Spd预处理增强黄瓜幼苗抗冷性的效果最好，具体表现为显著增加干物质和含水量，显著降低叶片冷害指数、电解质渗漏率和丙二醛（MDA）含量，显著增强超氧化物歧化酶（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，显著提高抗坏血酸、脯氨酸和可溶性糖含量，还能维持较高的根系活力。

Effect of Spermidine on Chilling-tolerance in Cucumber Seedlings

Cucumber seedlings with two true leaves which were spread by spermidine(Spd) of different concentrations were used to study the effect of Spd on their growth, physiological and biochemical characteristics under 5℃ for four days in order to ascertain effects and physiological mechanisms of Spd on chilling tolerance of cucumber. The results showed that Spd at 050 mmol·L^-1 is more effective in improving chilling tolerance of cucumber seedlings. Pretreatment of Spd could improve increase of dry matter and water content, obviously decrease chilling injury index, electrolytic leakage and malondialdehyde(MDA) content, significantly increase activities of superoxide dismutase (SOD), peroxidase(POD), catalase(CAT) and ascorbic peroxidase(APX), content of ascorbic acid, proline and soluble sugar, maintain higher root activity.