Effects of plant density and nitrogen fertilizer on carbon and nitrogen metabolism of weak-gluten wheat variety Ningmai9 were studied.N content in plants reached its peak at the beginning of over-wintering,then gradually decreased with growth and development.Total soluble sugar content was high at over-wintering,booting stage and anthesis,but low at the jointing stage.The change of C/N ratio was similar to that of total soluble sugar content.Total soluble sugar content and C/N ratio in plants at jointing st...