Effect Of PH And Fe²⁺ Stress On The Activities Of Enzymes In Plasma Membrane Of Alfalfa(Medicago Sativa L.) Root

Alfalfa(Medicago sativa L.) genotypes WL525((Medicago sativa cv. WL No.52) and Suntory(Medicago sativa cv. Suntory) were used to study change of ATPase and redox system enzymes in plasma membrane of alfalfa prepared by sucrose gradient sedimentation under acid stress, Fe stress and both acid and Fe stress.Conclusions were as follows:1) Activity of H⁺-ATPase of two alfalfa genotypes increased firstly and then decreased under acid and Fe stress. The results of activity of H⁺-ATPase were different between two genotypes of alfalfa;2) Activity of Ca²⁺-ATPase of two alfalfa genotypes increased firstly and then decreased under acid and Fe stress. The results of activity of H⁺-ATPase were different between two genotypes of alfalfa;3) Change of Mg²⁺-ATPase in plasma membrane of two afalfa genotypes was the same under acid stress. Activty of Mg²⁺-ATPase increased under acid stress. Activty of Mg²⁺-ATPase increased firstly and then decreased under deficient Fe stress and under both acid and excessive Fe stress. Activity of Mg²⁺-ATPase decreased and then increased under excessive Fe stress. Difference was present between two alfalfa genotypes;4) NADH oxidase in plasma membrane of two afalfa genotypes totally decreased firstly and then increased under acid and Fe stress. The results were different between two alfalfa genotypes.5) Activity of FCR decreased along with the increase of treatment time under acid stress and both acid and deficient Fe stress. Activity of FCR showed a trend of increase fistly and then decrease. The results were different between two alfalfa genotypes.6) Activity of EDTA-Fe³⁺ reductase increase along with the increase of treatment time under deficient Fe stress. Activity of EDTA-Fe³⁺ reductase increased and then decreased under the other stresses. The results were different between two alfalfa genotypes.