The Functions And Mechanisms Of Phospholipase Ds In Plants Responses To Drought Stress

The water resources shortage is a very serious problem in our country. And the drought is one of the worst natural disaster. Excellent forest tree species, which can adapt well to growing in drought conditions, must be very important to combating desertification, preventing and controling sand, afforesting and beautifying ecological environment, as well as to improving economic benefits. So researches that are about drought resistance ability and it's mechanisms of forest trees will be very important to arid area choosing afforestation tree species. Poplar is a kind of very important fast-growing economic forest. As a model plant of the transgen- ic trees, Poplar has some features that it is easy to be in vitro culture and be infected by agrobacterium. Via Agrobacterium-mediated approach, phospholipase Dα1 overexpression gene (PLDα1-OE),phospholipase Dδ1-RNAi gene (PLDδ1-RNAi) and phospholipase Dδ1 overexpression gene (PLDδ3-OE) were successfully introduced into populus for the first time. We made the mutant materials under drought stress conditions. After we detected their morphological indexes and drought-resistance physiological ind- exes such as the leaf WUE, membrane ion leakage rate, osmotic adjustment and so on. We analysised the functions and mechanisms of Phospholipase Ds in plants responses to drought stress. The major experimental results are described as follows:(1) By using transgene technology and plant tissue culture, we have obtained the populus wild-type, PLDα1-OE, PLDδ1-RNAi, and PLDδ3-OE transgenic populus.(2) Trough the experiment of controlling pots soil water contents, we found that the drought resistance of PLDα1-OE and PLDδ3-OE transgenic populus is higher than the wild-type populus. And the drought resistance of PLDδ1-RNAi transgenic populus is close to the wild-type populus.(3) On the drought-resistance mechanism research, we found that the overexpression of PLDα1 in populus improved the drought resistance of transgenic plants by osmotic adjustment mechanisms. And the overexpression of PLDδ3 in populus improved the drought resistance of transgenic plants by membrane stability regulation mechanisms.