Effects of Nitrogen Topdressing Stage on N Metabolism and Protein Compontents in Winter Cultivars with Two Spike-types

The field experiment was carried out to investigate the effects of nitrogen topdressing stage on nitrogen accumulation,transfer,assimilation enzymes and protein compontents in two wheat cultivars with different spike types.The results indicated that nitrogen topdressing at jointing stage increased N accumulation at anthesis and maturity and N transfer compared with nitrogen topdressing at turn green stage and heading.N translocation efficiency and N contribution proportion decreased with nitrogen topdressing stage delaying.GS activity of flag leaves in Lankaoaizao8 and NR in Yumai 49-198 increased with the nitrogen topdressing stage delaying,and NR activity of flag leaves in Lankaoaizao8 and GS in Yumai 49-198 took on above change rules in early filling with maximum of nitrogen topdressing at jointing stage in late filling.Albumin,gliadin,glutenin and total protein content increased with the nitrogen topdressing stage delaying,and globulin content decreased.The other protent content in Lankaoaizao8 decreased with the nitrogen topdressing stage delaying,and increased in Yumai 49-198.