Response of Salt Stress on Plant Growth,Photosynthetic Pigment and Membrane Permeability of Cauliflower Seedlings with Different Genotypes

In this paper,using the different genotypes of cauliflower seedlings(RZ-50 and YM-80) as tested materials,plant growth,water physiology,photosynthetic pigment and membrane permeability were investigated under different concentrations of NaCl(0,68 and 136 mmol·L-1).The result showed that the seedling height increment,leaf length and width,seedling fresh weight and dry weight, relative water content of plant and leaf,cell membrane stability index(CMSI),contents of chlorophyll b(Chl b),chlorophyll and carotenoid and Car/Chl ratio were reduced obviously by salt stress,especially at high concentration of NaCl(136 mmol·L-1).However,the content of malondialdehyde(MDA) and chlorophyll a/b(Chl a/Chl b) ratio increased significantly.While content of chlorophyll a(Chl a) changed differently with NaCl concentration or the cultivars. These results indicated that the decline of seedling growth was caused mainly by inhibition of water absorption,photosynthetic pigment synthesis and membrane integrity under salt stress. Moreover,a higher degree of the changes for seedling height increment,seedling weight,PRWC, LRWC,CMSI,Chl b,Chl and MDA was caused by NaCl in RZ-50 compared with that in YM-80.Therefore, salinity stress had stronger influence to RZ-50.The salt tolerance of YM-80 would be higher than that of RZ-50.