摘要 以黄瓜品种9930 为试验材料，研究低温（6 ℃）条件下叶面喷施肌醇（0.8 g · L-1）对植株抗性以及肌醇代谢关键基因肌醇加氧酶基因CsMIOX1 表达水平的影响。结果表明，低温条件下，与未喷施肌醇相比，外施肌醇能够显著提高植株的干鲜质量，降低电解质外渗率。低温胁迫下，外施肌醇处理的黄瓜叶片抗坏血酸（AsA）含量在处理后12～24 h 显著高于未施肌醇处理，在处理12 h 时达到最大值，比CK 增加131.27%。在低温处理24 h 后，外施肌醇处理的SOD 和POD 活性一直高于未施肌醇处理；在低温处理12～48 h 外施肌醇处理的H2O2 含量一直显著低于未施肌醇处理，至48 h 时，喷施肌醇处理的丙二醛含量显著低于未施肌醇处理；低温处理24 h 时，喷施肌醇处理的可溶性糖和脯氨酸含量显著高于未施肌醇处理，分别高出54.62% 和155.50%。外施肌醇后，肌醇加氧酶基因CsMIOX1 表达水平显著上升，外施肌醇促进了AsA 的合成。综上所述，外施肌醇能够缓解低温对黄瓜的伤害，提高植株在低温胁迫下AsA 含量和抗氧化酶系统的活性，提高植株抗冷性。
Abstract：Taking cucumber（Cucumis sativus L.）‘9930’as test material, this paper studied the effect of spaying myo-inositol（MI，0.8 g · L-1）on cucumber plant resistance and expression level of key gene - CsMIOX1（myo-inositol oxygenase gene）under low temperature（6 ℃）．The result indicated that under low temperature condition comparing with the treatment without spraying MI，spraying MI could significantly increase the biomass，decrease the electrolyte leakage rate．Under low temperature stress，the AsA contents of cucumber leaves treated by spraying MI were significantly higher than that of those without spraying MI 12-24 hours after treatment．The AsA content reached the maximum value，12 hours after treatment, which was increased by 131.27% than that of the CK．After 24 hours low temperature treatment，the SOD and POD activities of MI treatment were always higher than that of without MI treatment．After 12-48 hours under low temperature treatment，the H2O2 content of MI treatment was always significantly lower than that of without MI treatment．Until 48 hours，the MDA content in MI treatment was notably lower than that of without MI treatment．By 24 hours after chilling treatment, the contents of soluble sugar and proline of MI treatment were significantly higher than that of without MI treatment by 54.62% and 155.50%，respectively．After spraying MI，the expression level of CsMIOX1 went up significantly．Exogenous MI treatment stimulated the AsA composition．In conclusion，spraying MI can alleviate the damage of low temperature to cucumber，increase AsA content and activity of antioxidant enzyme system under chilling stress，and improve plant cold resistance．
