Effects Of Polyamine On Protein And Nucleic Acid Degradation And Drought-resistant In Wheat Seedlings Leaves Under Water Stress

The changes of polyamine oxidase(PAO) activity and their relations to drought-resistance were studied with two different drought-resistance changwu.131 and drought-sensitive cultivar zhengyin.1 under water stress. And by spraying Spm on wheat seedlings leaves, determined PAs content , proteinase ,nucleic acid enzyme and protect enzyme activities, protein, amino acid and nucleic acid content under water stress .the effects of different PAs on drought-resistance , protein and nucleic acid metabolize were discussed. The results were as follows: 1. During water stress, the contents of three PAs (Put, Spd, Spm) in wheat seedlings were quickly increased at the early stage and then decreased. Compared with drought-sensitive cultivar zhengyin.1, the contents of Spd and Spm increased more and decreased slowly in drought-resistance cultivar changwu.131 .The changes of Put in the two different drought-resistance cultivars were similar. Treatment with exogenous Spermine could increase the contents of three PAs in wheat seedlings, the change trend of PAs content conform with the changes of PAs under water stress. And the increment in Spd and Spm content in drought-sensitive Were lower than in the drought-sensitive one. The results showed that Spd and Spm may play a more important role in drought-resistance than Put.2. PAO activity in wheat seedlings increased firstly and then decreased under water stress. The increment in PAO activity were different between the two cultivars. Compared with the drought-resistance cultivar changwu.131, the PAO activity of the drought-sensitive cultivar increased greatly than drought-resistance one. The results indicated that the great increasing range of PAO activity may injured the stressed crop. 3. The Proteinase ,nucleic acid enzyme activities and amino acid content in wheat leaves of both drought-resistant.(changwu.131).and drought-sensitive (zhengyin.1) variety increased during water stress, which content of soluble protein and nucleic acid content decreased. The increment in proteinase, nucleic acid enzyme activities , amino acid content and the decrement in protein and nucleic acid content in the drought-resistant Variety Were lower than in the drought-sensitive one . Treatment with exogenous Spermine could delay the increase in enzyme activity , amino acid content and the decrease in protein and nucleic acid content, and treatment with exogenous Spermine could retard drought-sensitive Variety senescence better than drought-resistant one under water stress. 4. The SOD, CAT and POD activities in wheat seedling leaves of both drought-resistant.(changwu.131)and drought-sensitive (zhengyin.1) variety increased during water stress, and enhance permeability of plasma membrane and MDA content. Treatment with exogenous Spermine could enhance the increase in enzyme activity and delay the increase in permeability of plasma membrane and MDA content. And exogenous Spermine could retard drought-sensitive Variety senescence better than drought-resistant one under water stress.