Effects Of Carbon And Nitrogen Regulation At Post-anthesis On Source-sink Relation And Grain Quality Of Spring Wheat

The objective of this study was to explore the effects of spraying carbon and nitrogen on leaves on source-sink relation and grain quality of spring wheat. On the basis of previous study, two spring wheat varieties Kehan19(KH19) and Longmai33(LM33) were chosed as the study objects,and 5% sucrose and 2% urea was sprayed three times on the leaves from full heading stage. Dry matter accumulation,changes of glucose content of source and sink organs and grain quality was determined,to analyze source-sink relation of spring wheat and explore the influence of exogenous carbon and nitrogen on wheat quality. Main results were as follows:1. Spraying 5% sucrose on leaves decreased the dry matter weight of second flag leaves, second internode from top, and increased the decline range and the contribution to sink organs of dry matter translocation of source organs such as flag leaves and second flag leaves; spraying 2% urea increased dry matter weight of second flag leaves, first internodes from top and spikes, and decreased the contribution of dry matter translocation of flag leaves to sink organs.2. Spraying 5% sucrose and 2% urea on leaves decreased soluble sugar content in source organs such as flag leaves and second flag leaves and grains; spraying 2% urea on leaves increased soluble sugar content in source organs such as flag leaves and first internodes from top, and meanwhile decreased soluble sugar content in sink organs such as cobs and grains. Spraying 5% sucrose and 2% urea increased starch content in grains of wheat in different periods.3. Spraying 5% sucrose and 2% urea on leaves increased grain filling rate by 12.8%~38.1%, the effects of spraying 2% urea were more significant. Spraying 5% sucrose increased grain number per spike of KH19 and LM33 by 11.9% and 9.5%; while spraying 2% urea increased grain number per spike by 20.6% and 8.9%, 1000-kernel weight by 4.6% and 7.2%, and yield by 16.9% and 15.8%. Spraying 2% urea increased protein content, wet gluten content and sedimentation in grains of LM33 by 6.2%, 5.5% and 14.7%.4. Spraying 5% sucrose increased flour water absorption of LM33 by 2.8%; spraying 2% urea increased flour water absorption of LM33 by 4.7%. Spraying 2% urea extended dough stability time and breakdown time of LM33 by 26.7% and 12.5%, and decreased mixing tolerance index by 18.1%. Spraying 5% sucrose increased dough tenacity resistance, tenacity energy and tenacity ratio of KH19 by 10.8%, 8.7% and 9.1%,and inceased dough tenacity energy and tenacity ratio of LM33 by 7.9% and 5.0%. Spraying 2% urea increased dough tenacity energy and tenacity ratio of KH19 by 8.7% and 9.1%,and inceased dough tenacity energy and tenacity ratio of LM33 by 6.7% and 5.0%...