水杨酸对黄瓜幼苗生理的影响

EFFECT OF SALICYLIC ACID ON GROWTH OF CUCUMBER SEEDLING

为了明确不同浓度外源水杨酸(Salicylic acid,SA)处理对黄瓜幼苗生长的影响,以黄瓜品种"中农203号"(Cucumis sativus L.cv.ZhongNong 203)为试材,采用水培方法设计根际0.05 mmol/L、0.1 mmol/L和0.5 mmol/L SA处理,研究黄瓜幼苗对SA的生理响应。结果表明:黄瓜幼苗叶片净光合速率(Pn)、胞间CO2浓度(Ci)、气孔导度(Gs)、蒸腾速率(Tr)、叶绿素含量、植株含水量、电解质渗透率和MDA含量对SA的响应存在明显的浓度依存性和时间效应。0.05 mmol/L和0.1 mmol/L SA处理增加了Ci和叶绿素含量;降低了电解质渗透率和MDA含量,提高了Pn,以0.1 mmol/L SA处理效果最佳;而0.5 mmol/L SA处理降低了Ci和叶绿素含量,提高了Tr,最终导致Pn下降。结果表明,适宜浓度的SA处理有利于幼苗的生长。

This work was performed to illustrate the action mechanism of exogenous salicylic acid （SA） on growth of Cucumber seed- ling. utilizing the material of cucumber seedling cultivated in nutrient solution supplemented with 0.05 retool/L, 0.1 mmol/L and 0.5 mmol/L SA. The results showed that net photosynthetic rate （Pn）, intercellular CO2 concentration （Ci）, stomatal conductance（ Gs）, transpiration rate（ Tr）, chlorophyll content , water content of plant , MDA content and permeation rate of electrolyte were responded to exogenous SA, and existed dose - dependent. 0.05 mmol/L and 0.1 mmol/L SA increased, intercellular CO2 concentration （Ci） and chlorophyll content ; Compared to control, both 0.05 mmol/L and 0.1 mmol/LSA reduced MDA content and permeation rate of elec- trolyte, which finally improved Pn, and the function of 0.1 mmol/L SA was appeared more strong. However, exogenous SA at the con- centration of 0.5 mmol/L declined intercellular CO2 concentration （Ci） and chlorophyll content, and enhanced transpiration rate （Tr）, resulted in the decrease of Pn. These results revealed that the positive or passive regulation of exogenous SA on growth of Cucumber seedling.