Effects of Planting Density on Activities of Nitrogen Metabolism Enzymes in Flag Leaves and Grain Protein Content in Winter Wheat with Two Spike Types

Two winter wheat(Triticum aestivum L.) cultivars,Yumai 49-198 with multi-spike and Lankao Aizao 8 with large spike were used to investigate effects of planting density on the activities of enzymes related to nitrogen metabolism and grain protein content.We found that the planting density significantly affected the activities of enzymes.In the first 15 days after anthesis,the activities of glutamine synthetase(GS) and glutamate synthase(GOGAT) in flag leaves of both cultivars were improved with the increase of planting density,and meanwhile nitrate reductase(NR) activity in flag leaves was the lowest in middle density treatment.In a certain range,the grain protein content was enhanced with the increase of planting density for both cultivars.The results indicate that the increase of the activities of enzymes related to nitrogen metabolism benefits the accumulation of grain protein.