Effect of Nitrogen Applying Stages on Senescence Characteristics of Flag Leaves in Winter Wheat Bainongaikang 58 after Anthesis

Under the high-yield planting condition,the effects of nitrogen applying stages on the physiological indices related to senescence of flag leaves in winter wheat Bainongaikang 58 were studied.The results showed that the nitrogen topdressing in erecting stage or jointing stage could significantly increase the photosynthetic rate,inhibit the degradation of chlorophyll,maintain the higher activity of superoxide dismutase(SOD),and reduce the malondialdehyde(MDA) content.