弱光下长期亚适温和短期低温对黄瓜气孔特性及叶绿体超微结构的影响（征文）

摘要：　为了探讨弱光下长期亚适温和短期低温对黄瓜叶片光合机构的影响机理的差异，本文研究了两种逆境对黄瓜气孔特性及叶绿体超微结构的影响。结果表明，长期（7d）弱光亚适温处理（Ⅰ）后，黄瓜叶片的Gs和Ci降低；短期（3d）弱光低温处理（Ⅱ）的Gs明显降低，而Ci升高。条件改善后，前者的Gs和Ci均上升；而后者的Gs增加，Ci降低。处理后当天测定，长期弱光亚适温处理叶片的气孔多数处于关闭状态，而短期弱光低温处理的气孔开张比和开张度显著大于CK。表明较长时间的弱光亚适温处理Pn的降低与气孔开度减小显著相关；而短时间的弱光低温处理Pn降低的主要原因是叶肉因素。长期弱光亚适温处理后淀粉粒数明显减少，而短期弱光低温处理黄瓜幼苗的生长过程基本停止，物质运输严重受阻。

Effects of Suboptimal Temperature and Low Temperature under Low Light Intensity on Stomatal Characteristics and Chloroplast Ultrastructure of Cucumber Seedlings

Abstract: The effect of suboptimal temperature for 7d（Ⅰ）and low temperature for 3d (Ⅱ) under low light intensity on stomatal characteristics and chloroplast ultrastructure of cucumber leaves were studied for research the difference between suboptimal temperature for long time and low temperature for short time under low light intensity on photosynthetic mechanism of cucumber leaveve. The result showed that the stomatal conductance (Gs) and Intercellular CO2 concentration (Ci) of treatmentⅠdecreased. The Gs of treatment Ⅱ reduced remarkably, while the Ci raised. When the condition improved, the Gs and Ci of treatmentⅠascended. The Gs of treatment Ⅱ increasd, but Ci decreased. Most stomata of treatmentⅠ were closed, and the stomatal aperture were minished obviously. But that of treatment Ⅱ showed a marked increase over CK. It suggested that the decrease in Pn of treatmentⅠwas closly related with the reduction in size of stomatal aperture, while that of Ⅱ was mainly caused by factors of CO2 assimilation. The number and size of starch grains of treatmentⅠdecreased remarkably, but little changes was observed in treatment Ⅱ. It indicated that the carbohydrate of treatmentⅠreduced, the matter transportation of treatment Ⅱwas restricted.