Effect Of Zinc On The Physiological And Biochemical Characteristics And Photosynthetic Characteristics In Broccoli Seedlings Leaves Under Drought Stress

This study took the broccoli (Brassica oleracea L.var Italicap) seedlings leaves as the experiment material, with the 10mg/L peroxide solution carried on processing including Zn²+ to the material. Through having been determinated the broccoli seedlings leaves'Osmotic regulation ability,Cell membrane penetrability,Membrane fat peroxidation level,Protection enzyme and Oxidation resistance material changes,and the exchange of gases parameter as well as the chlorophyll fluorescence parameter's change and so on, under the optimum relative of soil for 80-85%(CK),50%-60%(moderate drought)and 40%-50%(heavy drought), has studied the effect of Zinc on the physiological and biochemical characteristic and the exchange of gases parameter, the chlorophyll fluorescence parameter's influence and mechanism in the broccoli seedlings leaves under drought stress. The mainly results were shown as follows:1.Under the drought stress,broccoli seedlings leaves' MDA content and the cell membrane penetrability increased.And the bigger coercion degree was, the bigger increased scope to be. the broccoli seedlings leaves' protective enzymes activity such as: SOD, APX, CAT as well as oxidation inhibitors content AsA, GSH and so on. Displayed the same changes tendency of drop quickly. But firstly, the protective enzyme POD activeness appearing rised, and then droped. Executing zinc enhanced broccoli seedlings leaves' the oxidation inhibitors of AsA, GSH contents and protective enzymes of POD, SOD, CAT as well as the APX activeness under drought stress.Alleviated the drought stress to the broccoli seedlings leaves's oxidized damage function. The blade antioxidation ability enhanced.2.Under the drought stress , broccoli seedlings leaves' Pr and Pro increased. and the bigger coercion degree was, the bigger increased scope to be. Executing zinc obviously reduced Pro content and increased Pr under drought stress. the broccoli seedlings leaves anti-arid ability reinforced.3.Arid coercion caused to the photosynthesize (Pn),the blowhole leading (Gs) and transpiration rate (E) dropped and rose in the intercellular CO2 concentration(Ci). After adding the zinc, each process of Pn, Gs and E drops'amplitudes significantly decreased, which caused by drought stress. Broccoli seedlings leaves' photosynthesis is forced the influence of arid coercion to reduced.Under the mild drought coercion, which the blowhole factor caused the Pn drops , But under the weight drought coercion the Pn drops'reason was the non-blowhole limit.4.Under the drought stress ,The broccoli seedlings leaves' Fv/Fm,Ñ„PSâ…¡, qP and Fv '/Fm' reduced significantly. occurrenced photo inhibition. Had no significant effect on broccoli seedlings leaves' Fv/Fm, Fv' /Fm',qP andÑ„PSâ…¡under the drought stress , after adding the zinc. Applied the zinc improved the broccoli seedlings leaves'photo inhibition capability'sresistance.