Effects of Nitrogen Application Rate on Carbon and Nitrogen Transportation in Winter Wheat Effects of Plant Density and Seeding Date on Accumulation and Translocation of Dry Matter and Nitrogen in winter Wheat Cultivar Lankao Aizao 8 Characterization of Starch Accumulation and Activities of Enzymes Involved in Starch Synthesis in Grains of Wheat Cultivars Differing in Spike Types Field-Grown in Irrigation and Rainfed Conditions Effect of planting density on nitrogen uptake, utilization anddistribution in winter wheat Photosynthetic Characteristics and Antioxidative Metabolism of Flag Leaves in Responses to Shading during Grain Filling in Winter Wheat Cultivars with Different Spike Types Effects of  Plant Density on Grain Number and Grain Weight at Different Spikelets and Grain Positions in Winter Wheat Cultivars Study on dynamic changes of starch accumulation in grain and related enzymes in winter wheat cultivars with two spike types The Relationship between Source-sink Intensity and Starch Accumulation during Grain Filling Period in Two Winter Wheat Cultivars with Different Spike Types REGULATING EFFECT OF DENSITY AND TOP-DRESSING TIME OF NITROGEN FERTILIZER ON ~(14 ) C-ASSIMILATION AND DISTRIBUTION OF ASSIMILATE OF LARGE-SPIKE CULTIVAR OF WHEAT Effects of P Deficiency on Photosynthetic Characters and Yield in Two Wheat Cultivars with Different Spike Types