Effect Of Source-sink Regulation On Dry Matter Production And Stem-sheath Reserve Transport Of Maize

Through cutting 50% leaf, spike and root of seven source-sink regulation treatments of two different type maize (Hudan4 and Shaandan902) in two different density (45000 plants/hm2 and 75000 plants/hm2) in 2002 and 2003. It was studied that the effect of source-sink relationship in different colony, dry matter production, accumulation and transport and yield by source-sink regulating. The following results were obtained: Dry matter accumulation decrease greatly in mature stage and in silking-mature stage when the source-sink was regulated through cutting leaf, spike and root, but the effect of dry matter accumulation in silking-mature stage was greater than in mature stage. The decrement of dry matter accumulation is diversity to two different type maize and two different density colony. The dry matter send-out in stem, leaves and sheathes is different remarkably when the source-sink was changed. Reducing source accelerate the export of phytosynthates production and reducing sink accelerate the accumulation of dry matter. The content of carbohydrate(such as soluble sugar and starch and sucrose) of plant nutrition organs was also affected remarkably with reducing source and reducing sink. Cutting spike causes the content of carbohydrate enhance remarkably, but cutting leaf and cutting root cause the content of carbohydrate reduce remarkably and the decrement of cutting leaf was higher than the decrement of cutting root. Reducing source through cutting leaf and cutting root can decrease the residual ratio in stem-sheath and the chlorophyll content of leaf, on the contrary reducing sink through cutting spike can increase the residual ratio in stem-sheath and the chlorophyll content of leaf. When the source-sink was regulated the supply ability of plant and LAI are decreased remarkably, and the single plant productivity is also reduced prominently. The key reason of reduction yield with cutting spike is that the grains spike is reduced, but when the source-sink of over the earth is reduced 50% at the one time, the reason of reduction yield is that the grains spike and thousand grains weight is reduced. The sink-source ratio has suitable scope, and it relate to intimately the validity of phytosynthates. The key of yield getting higher is setting up source-sink character (up-ground part and underground part) high level in the base of improving source (leaf and root) character of plant . plant nutrition organs...