水杨酸对黄瓜子叶表皮气孔开度的调节作用

以黄瓜品种中农203(Cucumis sativus L.cv.Zhongnong 203)幼苗为试材,采用SA溶液根部施用和子叶表皮浸泡两种方式,显微观测了不同外源水杨酸(Salicylic acid,SA)溶液处理对其子叶表皮气孔开度的影响,以探讨SA与气孔运动的关系.结果表明:SA子叶表皮浸泡或根部施用后,气孔运动的趋势是随着SA浓度增加而孔径逐渐变小,且SA磷酸缓冲液的作用效果与SA水溶液相似.随着处理时间的延长,气孔开度逐渐变小,且气孔开度与SA处理时间达极显著(r=-0.962**)或显著(r=-0.914*)负相关.溶液低pH值,增强了SA对气孔开度的抑制作用,且SA浓度越高作用越明显;0.1 mmol/L SA处理后,pH为8、7、6溶液的气孔开度抑制率分别为90.2%、93.8%和96.3%,即SA溶液对气孔开度的抑制率随着溶液pH降低而升高.可见,外源SA能够促进气孔关闭,其作用随着SA浓度升高、处理时间延长和溶液pH值降低而增强,相对于磷酸缓冲液,以蒸馏水作为溶剂的SA溶液促进气孔关闭的作用更大.

Regulation of Salicylic Acid on Stomata Aperture of Epidermis in Cucumber Cotyledon

The influence of exogenous SA on stomata aperture of cotyledon epidermis was investigated by means of microscope,using cucumber seedling(Cucumis sativus L.cv.Zhongnong 203),the relationship between salicylic acid(SA) and stomata movement was analysed.The results revealed that stomata aperture gradually diminished accompany with concentration of SA increasing,and the effect of SA dissolved in phosphate buffer was similar to SA dissolved in distilled water.Meanwhile,stomata aperture became smaller along with the time of SA application prolonging,and there existed extremely significant(r=-0.962) or significant(r=-0.914) negative correlation between stomata aperture and the time of application.Lower pH of solution enhanced the limited function of exogenous SA to stomata aperture,and higher concentration of SA was appeared more obvious.SA was the most effective at pH 6,at concentrations of 0.1 mmol/L(pH 8:90.2%;pH 7:93.8%;pH 6:96.3%) compared to the control at corresponding pH.The results suggested that exogenous application of SA to incubate epidermis of cotyledon or to roots in cucumber seedling could induced stomata closure,which was intensified by high concentration,long time,low pH of SA solution,and SA dissolved in distilled water appeared more effective compared to in phosphate buffer.