关键词: 弱光, 长期亚适温, 短期低温, 气孔, 黄瓜

Abstract: 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.

Key words: Low light intensity, Suboptimal temperature for long time, Low temperature for short time, Stomatal, Cucumber