Regulating Effect Of Exogenous Polyamines On Membrane Lipid Peroxidation Of Winter Wheat (Triticum Aestivum L.) Seedlings Under Drought Stress

Polyamine relations to drought resistance were studied with two different drought resistance caltivar(sluohan 6 and zhengmai 9023)under drought stress. the use of water culture method to study the exogenous polyamines on membrane lipid peroxidation and osmotic adjustment of organic substances in winter wheat seedling leaves. At the same time, the effects of different Pas on drought resistance were discussed. The results were as follow:1, Under normal conditions, the relative water content and chlorophyll content were little changed in winter wheat seedling leaves in the 48h. At the same time, there is a dynamic balance between MDA content, membrane permeability, H₂O₂content, O₂^-.production rate and antioxidant enzymes (SOD, POD, CAT) of activity, organic osmolyte (RSC, TFA, Pro) in winter wheat seedling leaves.2, Under the conditions of drought stress, the relative water content and chlorophyll content decreased were rapidly compared with pre-stress in winter wheat seedling leaves, the MDA content and membrane permeability were dramatic increased, the antioxidant enzymes (SOD, POD, CAT) activity had increased over a period of time after stress, but there was downward trend in the late stress, organic osmolyte (RSC, TFA, Pro) contents increase amplitude were reduced. The results indicat that, broked the balance between the drought stress generate reactive oxygen species and the ability to remove harmful of enzymatic system and non-enzymatic system. It had damage to the normal growth of winter wheat.3, Under the conditions of drought stress by adding exogenous polyamines (Put, Spd, Spm), the exogenous polyamines lowered the decreased extents of relative water content (RSC) and chlorophyll, increased membrane permeability, increased MDA content; the antioxidant enzymes (SOD, POD, CAT) activity was increased, the organic osmolyte (RSC, TFA, Pro) content was increased, while the Pro/TFA was improved. So that the osmotic adjustment ability of winter wheat to be strengthened, to maintain a lower osmotic potential, to improve water-retention capacity, thus, the drought resistance of winter wheat seedlings was improved.4, Under the conditions of drought stress, Polyamines improve the mechanism of drought resistance of winter wheat is: the activity of antioxidant enzymes he accumulation of organic material penetration Polyamines in leaves of winter wheat, increased osmotic adjustment ability, ease of blade membranaceous peroxide, reduced the infiltration of cells potential to improve the water-retention capacity of leaves and chlorophyll content, maintaining the normal physiological functions of leaves. For luohan 6, Spd and Spm are the main factors of drought resistance; for zhengmai 9023, Put and Spm are the main factors of drought resistance.