Effect of Salt Stress on Photosynthetic Characteristic and Relevant Gene Expression of Cucumber Seedling
SUN Chao1，SHAN Nan1，WANG Hui-juan2，ZHANG Ying-jia1，WANG Zhen-yu1，3，ZHANG Zhenxian#br# 1，SUI Xiao-lei 1*
1 College of Horticulture，China Agricultural University，Beijing Key Laboratory of Growth and Development Regulation
for Protected Vegetable Crops，Beijing 100193，China；2 Ecology Laboratory，Beijing Ecotech Science and Technolog
Ltd，Beijing 100190，China；3 Beijing High-quality Agro-Products Servic Station，Beijing 100101，China
Photosynthesis is one of the plant relatively sensitive physiological metabolism reaction to
salt stress．This experiment took 2 cucumber varieties‘ Zhongnongda No.22’ and‘ Deltastar’ with different
sensitiveness to salt stress as material to study photosynthetic responses to salt stress． The results showed that the
photosynthetic pigment（chlorophyll and carotenoid）contents，net photosynthetic rate，dark respiration rate and
transpiration rate of cucumber seedlings decreased significantly under salt stress．The number of thylakoid lamella
of chloroplast was reduced greatly and starch grains became fewer and smaller when cucumber seedling treated
with salt stress．With the process of salt stress，the expression levels of rbcL，encoding the large subunits of
Rubisco（ ribulose-1，5-bishosphate arboxylase/oxygenase）and Csppc2，encoding PEPC（phosphoenolpyruvate
carboxylase） increased first then decreased，while the enzyme activity of Rubisco and PEPC declined
remarkably．Compared with‘ Zhongnongda No.22’，‘Deltastar’ had better tolerance to salt stress．
