| Improvement and Cultivation in Cold Region,Daqing,Heilongjiang 163319,China)Post-anthesis nutrient regulation has been regarded as promising way to increase yield in agronomic practices. In order to explore the effect of different nutrient regulation at post-anthesis on increasing yield,spring wheat variety Longmai 33 was used as test materials,and exogenous sugars and nitrogen (2% urea and 5% sucrose) were sprayed on the leaf. The dry matter accumulation at post-anthesis,the crop growth rate (CGR) of full heading stage,SPAD value,net photosynthetic rate,soluble sugar content and total nitrogen of flag leaves were analyzed. The results showed that,compared with control (CK),exogenous sugar and nitrogen appliclation could increase yield (by 6.86% for sucrose and 15.82% for urea),grain number and 1 000-kernel weight The post-anthesis dry matter accumulation ratios in grain and its contribution to grain yield were both high,and exogenous sugar was better. The exogenous sugar and nitrogen significantly promoted CGR,while it was positive related to contribution of yield. The exogenous nitrogen application could significantly increase harvest index (HI) in comparison with control,while HI was declined with the exogenous sugar (by 11.76% for spraying urea,0.085% for spraying sucrose). The exogenous nitrogen had positive effects on chlorophyll content (SPAD value),while exogenous sugar reduced it. The exogenous sugar and nitrogen application could increase net photosynthetic rate (Pn) and total nitrogen in the flag leaves,while soluble sugar content,soluble sugar content and total nitrogen ratio (C/N) were decreased. The results indicated that the change of C/N had interaction on higher yield. |
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