Dynamic Variation for Biomass and Nitrogen Absorbing Amount and Nitrogen Physiological Efficiency in Oilseed Rape

The dynamic variation for biomass,nitrogen absorbing amount and nitrogen physiological efficiency of oilseed rape during their growth developmental stages were studied.The result indicated that the biomass continuously increased with growing period,and their accumulations with time could be described by a S-curve shaped exponential regression equations.By differentiating the regression equations of dry matter accumulation,the rate of dry matter accumulation was obtained,which varied with different growing period.The maximum dry rate appeared during the126～156th days after sowing.Nitrogen absorbing amount increased fast from seedling stage to bud stage;decreased from bud final stage to flowering final stage;slowly increased at the end of flowering stage.Nitrogen’s contents continuously decreased with growing period and that in generative organs obviously higher than that in nutritive organs after reproductive stage.Nitrogen physiological efficiency varied slightly before flowering stage and then obviously increased,finally reached their peak in siliquing period.