| The distribution of 14C-photosynthate in plants , main stems and tillers in three wheat varieties (9559 with low tillering percentage and earing percentage,Yangmai 12 with medium tillering percentage and earing percentage and Xuzhou 26 with high tillering percentage and earing percentage) at different growth stages was studied on the experimental field of Crop Cultivation and Physiology Key Laboratory of Jiangsu Province,Yangzhou Uinversity in 2001-2003.The main results were as follow:1. Distribution of 14C-photosynthate in plants at different growth stagesThe 14C-photosynthate produced at each growth stage was mainly used for the development of growth center. The difference of 14C-photosynthate distribution proportion in different organs among three varieties was not significant at tillering stagejointing stage and heading stage.The 14C-photosynthate temporarily stored in leaves and stems could be transported to grains from heading stage to maturity. At maturity,the proportion of 14C-photosynthate produced at heading stage in grains was highest for Xuzhou 26,but lowest for 9559. The difference of 14C-photosynthate distribution proportion in main stems and tillers among three varieties was significant. During the whole growth period, the ratio of 14C-photosynthate in main stems to the whole plant was significantly higher than that in any tiller in 9559 with low tillering and earing percentage. With the growth of plant, the difference of 14C -photosynthate distribution percentage between main stems and tillers became less in Yangmai 12 and Xuzhou 26 with medium and high tillering and earing percentage respectively, but the 14C-photosynthate ratio of tillers to plant in Xuzhou 26 was significantly higher than that in 9559 and Yangmai 12. The earing percentage of tillers and grain starch content increased with the increase of 14C-photosynthate ratio of tillers to plant in three varieties.2. Transportation and distribution of 14C-photosynthate produced in main stemsAt tillering stage, 83-87% of 14C-photosynthate produced in main stems was used for the growth of main stem itself. 6.15% and 5.92% of 14C-photosynthate were transported from a main stem to tiller I and II respectively in Xuzhou 26,while only4.38% and 3.84% in 9559. At jointing stage, 95-96% of 14C-photosynthate produced in a main stem was used by main stem itself, among which, 42.37-43.51% in the labelled leaf blade, 48.03-49.97% in the stem and leaf sheath. At heading stage, about 97% of C-photosynthate produced in a main stem was used by itself, among which, 36% in the labelled leaf blade, 24% in the spike, 34.73-35.17% in the stem and leaf sheath. At maturity, the proportion of 14C-photosynthate produced at heading stage in the labelled leaf blade, stern and leaf sheath declined and that in grains (32.76-41.81%) was the highest among all organs.3. Transportation and distribution of 14C-photosynthate produced in effective tillersAt tillering stage, 91.28-92.84% of 14C-photosynthate produced in an effective tiller (tiller II) was kept in its leaves and stem, 2.89-4% 14C-photosynthate was transported to the main stem, while only very little was allocated to the rest tillers. At jointing stage, more than 95% of l4C-photosynthate produced in an effective tiller was kept in the tiller itself, among which, 50% was transported to its stem and leaf sheath. At heading stage, more than 97% of 14C-photosynthate produced in an effective tiller was used by the tiller itself,among which, about 24% was supplied to the spike and about 35% to the stem and leaf sheath. From heading stage to maturity, l4C-photosynthate produced in an effective tiller was transported and distributed within the organs of the effective tiller, the l4C-photosynthate proportion in grains was the highest among all organs. So the l4C-photosynthate produced in an effective tiller was mainly used by itself, only little could be transported to the other rest effective tillers and ineffective tillers.4.Transportation and distribution of l4C-photosynthate produced in ineffecti... |
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