Effects of NaCl Stress on the Content of Photosynthetic Pigments in the Leaves of Cucumber(Cucumis sativus L.) Seedlings
WANG Su-ping,GUO Shi-rong~*,HU Xiao-hui,LI Jing,JIAO Yan-sheng(College of Horticulture,Nanjing Agricultural University,Nanjing 210095,China)
The effects of different NaCl levels(0,25,50,75, 100 mmol/L) on the contents of chlorophyll and carotenoid in the leaves of two cucumber cultivars(Cucumis sativus L.cv.'Changchun Mici' and 'Jinchun No.2') seedlings with different salt tolerance grown hydroponically were investigated.The results showed that the contents of chlorophyll a,chlorophyll b,total chlorophyll and carotenoid in the upper leaves of the two cucumber cultivars' seedlings began to increase after 1 day of exposure to salt,and reached their peaks on the 3rd day or 5th day under saline stress,and their contents increased with increasing salinity at the same time,then declined on the 7th day or the 9th day of exposure to salt.For the salt resistant cv.'Changchun Mici',the contents of chlorophyll and carotenoid increased earlier than those of the salt sensitive cv.'Jinchun No.2',however,the magnitudes of such increase were less as compared to the latter cultivar.In addition,car/chl ratio declined in the leaves of salt treated seedlings,and showed larger reduction in cv.'Jinchun No.2' than cv.'Changchun Mici'.In the lower leaves of cucumber seedlings subjected to salinity,the contents of the total chlorophyll and carotenoid reduced more than the control plants.