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Studies On The Physiological And Biochemical Responses And Adaptable Mechanism Of P.cornutum And P.dolabratum Seedlings Under Drought Stress

Posted on:2006-07-14Degree:MasterType:Thesis
Country:ChinaCandidate:D Y YangFull Text:PDF
GTID:2120360152495684Subject:Vegetable science
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P.cornutum and P.dolabratum were used as experimental material in this research. The effect of artificial imposed drought stress on physiological and biochemical responses and its adaptable mechanism had been studied.The results were as the following: 1) Under drought stress, the leaves relative water content(RWC),index of unsaturated fatty acid(IUFA) and chlorophyll(Chl) content of P.cornutum and P.dolabratum gradually decreased, while malonadhyde(MDA) content and plasma membrane relative permeability(PMP) increased significantly. PMP correlated negatively to RWC,IUFA,Chl and positively to MDA.The range of RWC,IUFA,Chl decreased and MDA,PMP increased of P.dolabratum was smaller than that of P.cornutum, which implied P.dolabratum has lower membrane-lipid peroxidation level,better membrane stability,lower Chl degrading level and longer leaf live under drought stress. 2) Under drought stress, the activity of superoxide dismutase(SOD) and peroxidase(POD) of P.dolabratum was to increase evidently at first then decreased, and its catalase(CAT) activity slowly increased.However, the SOD activity of P.cornutum increased after dropped, and activity of POD and CAT increased obviously at beginning of drought stress then dropped; ascorbic acid(AsA) content of P.cornutum and P.dolabratum always raised. AsA conteng of P.dolabratum is higher than that of P.cornutum , but the range of AsA content increased of P.dolabratum is lower. 3) the soluable protein(Pr) of P.cornutum and P.dolabratum fell gradually with the aggravating of drought stress,but the accumulation of proline(Pro) prompted on line. time of Pro increased was earlier and the number of Pro accumulated.larger. 4)the endogenous hormones content and the balance among endogenous hormones all changed under drought stress. The change of endogenous hormones has remarkable species different at the different pant and different drought stress level. 5) Under drought stress, there is a notable difference on the changes of the phenolic acids content of the P.cornutum and P.dolabratum. On the whole, the phenolic acids content of the root and leaf of P.cornutum decreased, but the P.dolabratum have a increased trend.so we can draw a conclusion that the different species exist different secondary metabolism. The physiological and biochemical responses and the adaptable mechanism of the P.cornutum have obviously species difference with P.dolabratum bu the different growth environment and different gene type. Considering the whole responses, we deduce that the drought resistance of P.dolabratum is stronger than that of P.cornutum.
Keywords/Search Tags:P.cornutum, P.dolabratum, Drought stress, Antioxidativity system, Membrane-lipid peroxidation, Endogenous hormones
PDF Full Text Request
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