Preliminary Study On The Relationg Of NADP-Malic Enzyme And Stresses

NADP-Malic enzyme was distributed widely in plants, which has many functions and plays important roles in plant physiological metabolism. The studies about NADP-malic enzyme are scattered now. And there is lacking of the systematic research about the relation between NADP-malic enzyme and the stresses. The relation between the NADP-malic enzyme activity and some plant physiological indexs (transpiration rate, stomatal conductance, photosynthetic rate and leaf water use efficiency) is less.We mainly investigate the NADP-malic enzyme activity and some plant physiological indexs (transpiration rate, stomatal conductance, photosynthetic rate and leaf water use efficiency) in wheat seedlings under ABA, SA, NaCl, PEG, Dark and Cold (4°C) stresses. And we also investigate whether there are closed relation between the NADP-malic enzyme activity and physiological indexs under different stresses though statistical analysis. On the basis of the above studies, we focus on the expression pattern of NADP-malic enzyme genes under different stresses in leaves and compare the difference of expression pattern in leaf, sterm and root in normally at the same time. We found that the NADP-malic enzyme activity is increasing before and decreasing after ABA, SA, PEG, NaCl stresses in leaves and strem. The activity is increasing along under dark and cold (4°C) stresses. The activity in leaves is higher in stressed seedlings than the normal seedlings. The transpiration rate, stomatal conductance and photsynthetic rate are decreasing under ABA, SA, PEG, NaCl, dark and cold (4°C) stresses. But the change of leaf water use efficiency is complex. The leaf water use efficiency is increasing before and decreasing after PEG stress. It has apparent distinctness compared with normal. The correlation between the NADP-ME and the leaf water use efficiency is very high and remarkable. The per-plant water use efficiency is highest under PEG stress. The leaf water use efficiency is not affected by NaCl stress. Though the analysis of expression pattern, we found that the gene expression mode in leaves, strem and roots is constitutive expression. The amount of expression is highest in leaves and lowest in roots. We also proved that NADP-malic enzyme is responding to the ABA, SA, PEG, NaCl, dark and cold stress at molecular level. The expression of gene NADP-ME2 is not investigated under dark stress. It means that the gene expression is regulated by light and the gene may belong to the photosynthesis gene. At last, we get the transgenic Arabidopis thaliana seedling by resistance screening. It lays a good foundation for future work.