Resistance Of Arabidopsis Thaliana Uxt Mutant To Drought Stress

In the natural environment,plants need to respond to a growing environment,including more and more stress environments,such as drought,cold,high salt,heavy metal pollution and other abiotic stresses.Response to abiotic stress is essential for plants,if plants do not respond to these changes in the environment actively,their Morphology,physiology,gene expression and material synthesis will be severely affected.In many abiotic stresses,drought plays a leading role in crop yield.Drought has a serious impact on agricultural production and social life.How to improve the drought resistance of crops and how to make the best use of limited fresh water resources for maximum agricultural production are the important issues that need to be solved urgently in the international and domestic biological science and technology.The use of molecular biological methods to cultivate drought resistant crop varieties is an economical and effective way to utilize the arid land.It will create a new way for the cultivation of new varieties of high efficient drought resistant crops.On the basis of the results of previous studies in our laboratory,the uxt1uxt2uxt3 and uxs3uxs5uxs6 triple mutants of Arabidopsis thaliana and the wild type were used as the research objects and materials.Drought stress was carried out on two mutants of uxt1uxt2uxt3 and uxs3uxs5uxs6 through soil drought and 20% PEG6000 treatment,Investigating the drought resistance and causes of the two mutants can provides a basis for the further developing drought resistant germplasm resources.The main results are as follows:1.We compared the drought tolerance of wild type,uxs3uxs5uxs6 and uxt1uxt2uxt3 triple mutants.After PEG simulated drought stress,the number and degree of leaf shrinkage of Arabidopsis thaliana increased with the prolongation of drought stress.The water loss rate and conductivity of two mutant leaves were lower than those of wild type,and thecontent of malondialdehyde,proline,soluble sugar and chlorophyll was higher than that of wild type,which showed that the two mutant could resist the oxidative damage caused by PEG simulated drought stress.2.The antioxidant protection level of wild type and two mutant was compared after exogenous PEG treatment.The activity of guaiacol peroxidase(POD),ascorbic acid peroxidase(APX)and superoxide dismutase(SOD)in uxt1uxt2uxt3 and uxs3uxs5uxs6 triple mutants all changed.Compared with wild type Col,POD and AXP activities of uxt1uxt2uxt3 and uxs3uxs5uxs6 mutants were lower,and SOD activity was higher than that of wild type.3.By measuring the chlorophyll fluorescence parameters of the plant,we can see that the plant has a gradual adaptation to the drought environment,the photosynthetic rate decreases first and then returns to the same level as that of the non stress.With the prolongation of the PEG drought stress time,the photosynthesis of the uxt1uxt2uxt3 and uxs3uxs5uxs6 three mutants and the wild type of photosynthesis.The difference between rate trend and rate is small.4.When soil drought was done,wilting mutant was first two mutants wilting,leaf yellow and stem lodging,and uxs3uxs5uxs6 and uxt1uxt2uxt3 mutants showed higher tolerance to soil drought.The contents of chlorophyll,proline,malondialdehyde and soluble sugar in wild type and two triple mutant after soil drought stress were measured,and the two triple mutants were obviously larger than those of wild type.Above all,the mutant of uxt1uxt2uxt3 and uxs3uxs5uxs6 has a certain drought resistance,and theirs drought resistance may come from the stress effect of the plant itself,that is,the accumulation of its own anti stress substances.