Effect Of N Application And Branches Removal On Embryo Development In Rapeseed

The dynamic changes of embryo dry weight under different N application and branches removal were imitated through the Richards equation. The dynamic growth of embryo cell under branches removal and shading were studied through paraffin slice up. The relation between hybrid rapeseed embryo growth and environment was as follows:1,The prophase elongate and the proportion of total elongate decreased, but middle and later elongate and their proportion increased as the increasing of nitrogen fertilizer. The embryo elongation on the main stem was little higher than that on the branches at same nitrogen application, but the elongation of each period and their proportion were similar. The duration of each period and the total duration did not change with the increase of N application, but the maximum velocity and the mean velocity of the middle and later stage on the elongation of cotyledon increased as the increasing of nitrogen fertilizer application. The elongation and mean velocity of each period increased evidently contrast to CK after branches removal, but the duration of each period and the proportion were the same to CK. The elongation of cotyledon decreased after shading.2,The prophase duration and elongating amount and their proportion of hybrid decreased evidently than that of their parents, but the middle and later duration and elongating amount of hybrid were higher, finally the duration and elongating amount of hybrid increased evidently. The average velocity, maximum velocity and average velocities of each period of the accumulation of embryo elongation of hybrid decreased evidently than that of parents.3,Because of the increasing of duration and dry matter in middle and late periods, the total duration and final dry weight of embryo were increased as the increasing of nitrogen fertilizer application. The average velocity, maximum velocity and average velocities of each period of dry matter accumulation of embryo all decreased as the increasing of N fertilizer application. The embryo dry weight on the main stem was higher than that on the branches at some nitrogen application. Through branches removal, the duration of middle and late periods were shortened and the total duration was 4.56 days shorter than that of control, but the average velocity of each period and final embryo weight were increased obviously. After pod shading, the embryo dry weight reduced about 2/3.4,The duration and weight and the proportion of total duration and weight of the embryo in prophase, hybrid varieties were littler than that of parents, but middle and later duration and weight and their proportion were contrary. It increased total duration and embryo dry weight of hybrid. The average velocity, maximum velocity and average velocities of each period of hybrid varieties were littler than that of parents. The path analysis indicated that the middle duration and the average velocity were the most important to the embryo weight, the path coefficient were 1.3539 and 0.4513 respectively.5,The cell of eight fission stage was much bigger, and decreased with the cell division and get the smallest at the fish torpedo period, then get more and more bigger, the cell of each parts were different at the ripening stage. The cell of the hybrid was different from their parents at the same period, but the cell of each variety at ripening stage was bigger than that of prophase. The cell of cotyledon fence, sponge tissue and hypocotyls get bigger after branches removal; the cotyledon fence cell get smaller but the cotyledon sponge get bigger evidently than the CK.