| Salinity is one of the major abiotic-stress limiting growth and induces various changes at physiological and proteomic levels in B.napus.In this study,Nannongyou No.3 was used as plant material.To research the effect of salt stress on growth and at physiological and proteomic levels of B.napus.The main contents and result are as follows:(1)The growth of B.napus under salt stress.In order to illustrate the growth.of B.napus seedling under salt stress,the indicators such as dry and fresh weight of root,third leaf,fourth leaf,aboveground and whole plant were determined at 7d after treatment with 200 mM NaCl.In comparison with the cooresponding control,the dry weight of root,third leaf,fourth leaf,aboveground and whole plant reduced by 75.4%,14.0%,39.9%,60.7%,63.0%,respectively.And the fresh weight reduced by 81.8%,43.1%,55.6%,70.0%,71.0%,respectively.The results showed that salt stress inhibited the growth of B.napus seriously.(2)The physiological effect of saflt stress as showed by of B.napus.To explore the the physiological response of seedlings of B.napus,water potential,electric conductivity and contents of chlorophyll,proline,MDA,Na~+ and activity of SOD,POD of the third leaf were determned at 1d,3d,7d after 200 mM NaCl treatment.The results showed:? At Id,3d,7d after the treatment,the water potential reduced by 6.98%,41.73%,38.41%,respectively in comparison with the control;? The activities of SOD increased by 26.6%,23.0%,24.6%,respectively,and the activities of POD increased by 1.42,7.67,2.08 fold,respectively;? The content of MDA increased by 72.2%,34.6%,24.7%,respectively;and the electric conductivity increased by 50.5%,58.9%,196.8%,respectively;? The content of proline increased 13.8,18.4,53.1 fold,respectively;and the content of Na+increased 2.36,6.51,8.92 fold,respectively.These results as a whole showed that on one hand,under salt-stress condtions,rapseed plants uptakes and accumulated excessive Na+,leading unbalance of water and ion in the leaves and physiological drought and the damage of cell membrane system;as indicted by the increase of electric conductivity.On the other hand,the plants inniated salt-tolerance mechanism as indicateded by increase of activitives of SOD,POD and the content of proline,to mitigate the damaging effects of salt-stress in B.napus.(3)Proteomic Changes in salt-treated seedlings of B.napus.To identify the proteins responded to salt stress in B.napus,the proteins expressed in the third developed leaf of B.napus cv Nannongyou No.3,were analyzed for protein abundance in the third leaf at 1d,2d,3d after salt-stress treatment.The MS analysis identified 23 differentially expressed proteins as from 45 protein spots on 2-DE gels.Among of them,21 proteins were up-reulated duing the period of treatment,while 10 proteins were down-reulated.Up-reulated proteins included that involved in defense(Fe superxide dismutasel),and photosynthesis(chloroplast ribulose-1,5-bisphosphate carboxylase,Lhcb6 protein),metabolism(thiazole biosynthetic enzyme),molecular chaperone(cpn60),respiration(malate dehydrogenase).Down-reulated proteins included photosynthesis(ATP synthase gamma chain),metabolism(glutamate-1-semialdehyde aminotransferase enzyme).Our results suggest that these proteins might play roles in adaptation to salt stress in B.napus.Based on the research of physiological and proteomic changes of salt-stressed seedlings in B.napus,the result indicates that salt stress inhibited the growth of B.napus seriously,water,ion,osmotic and ROS balance were disturbed;the response proteins to salt stress regulate multiple metabolic pathways to mitigate the damaging effects in B.napus. |
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