| The effects of soil drought and/or strong light treatments on the net photosynthesis rate (Pn) and the chlorophyll fluorescence were investigated using two rice cultivars, Oryza sativa L. ssp. Indica, cv. 9311 and Oryza saliva L. ssp japonica, cv. Nipponbare, and the differences of photosynthetic responses to above treatment were compared between these two rice cultivars. In order to elucidate the mechanisms of the effects of drought and/or strong light treatments on the photosynthetic characteristics, proteomic technique, i.e two-dimensional electrophoresis (2-DE) , was also used to analyze the changes of chloroplast membrane proteome changes under these treatments. The main results are as followings:1. Under the drought condition, both the net photosynthesis rate and the chlorophyll fluorescence (Fv/Fm and F'v/F'm) are decreased as the decreases in soil water content (SWC) and leaf water potential. But drought and strong light stresses have more inhibitory effects on leaf net photosynthesis rate and chlorophyll fluorescence of 9311 than those of Nipponbare. Additive effects are found when rice plants are exposed to both soil drying and strong light stresses. These results imply that 9311 is more sensitive to drought and strong light than Nipponbare.2. In order to study the effects of soil drying and strong light stresses on the expression of chloroplast membrane proteins, we have also developed an optimal method to purify chloroplast from rice leaves. The chloroplast-purified efficiency and the chloroplast integrality obtained are improved obviously by changing the content of Vc and pH of the extraction medium. The chloroplast integrality gained in this experiment is more than 90%.3. The technique platform of two-dimensional electrophoresis (2-DE) for plant menbrane proteome analysis was also established and optimized. Taking the IEF gel as the first dimensional electrophoresis for example, the optimal loading amout of protein sample was 80 μ g for silver stain and 700 μ g for CBB stainning. The isoelectric focusing protocol was pre-electrphoresis 200V for 15 min, 300V for 30 min, 400V for 30min. the optimal electrophoresis conditions, after loading the sample, were 400V for 18hrs and 1000V for lhr. If IPG gel was ued as the first dimensional electrphoresis, isoelectric focusing protocol was rehydraded for at least 12 hours; 500V for 1 hour, 1000V for 1 hour and then 8000V for several hours. The voltage X time should be up to 18000v hrs for 13cm gel and 52000 v hrs for 24cm gels. As for the second dimendional elctrophoresis, 12.5% SDS-PAGE gel waspreferred.4. Drought stress and the strong light stress haa significant effects on chloroplast membrane protein expression. Under drought condition, at least 5 new chloroplast membrane proteins expression were induced and 6 proteins expression stimulated by drought for 9311. Among the proteins induced by drought, there are 4 proteins induced by moderate drought and inhibited by high-grade drought. For Nipponbare, there are at least 10 new chloroplast membrane proteins expression induced and 3 proteins expression stimulated by drought, and among the proteins induced by drought, there are 7 proteins induced by moderate drought and inhibited by high-grade drought. When exposd to strong light conditions, there are at least 6 new chloroplast membrane proteins expression induced and 3 proteins expression stimulated by strong light for 9311. And there are 7 proteins expression restrained to a certain extent by strong light and 4 proteins expression restrained completely under strong light condition. As for Nipponbare, there are at least 1 new chloroplast membrane protein expression induced by strong light, 4 proteins expression restrained to a certain extent by strong light and 14 proteins expression restrained completely under strong light condition. Under both drought and strong light condition, there are at least 3 new proteins expression induced for 9311. And there are 7 proteins which expressed in drought treatment restrained to some extent and 8 proteins which ex... |
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