| This experiments were carried out in 2001 and 2002, at NUE experiment station , with tow rice cultivars Wuxiangjing 9 (Japanica) and H97-322 (Indicd) to study the effects of the amount of basic and tillering nitrogen (BT) on the population quality , yield and physiological characteristics in nitrogen uptake of rice . The results are as follows:1. (BT) played a decisive role to establish the foundation of the rice population quantity. With the amount of BT increasing , the increment of number of from critical stage of productive tillering(N-n) to enlongation satge(n-2) was more significant than from transplantation stage(SN) to N-n .Since the tiller emerged from N-n stage is harmful to rice population quality , BT should be decreased to promote the construction of nice rice population.2. The population quantity was determined not only by the number of individuals and the ratio of main stems to tillers, also depended on the rate of superior tiller (ST),inferior tiller (IT) and ineffective tiller (IET). The yield of ST of Wuxiangjing 9 was above 80% , and that of H97-322 was above 75% of total yield . By a contrast, IT and IET is not so important for grain yield of rice . But the existence of IT and IET exhausted the nutrition restricted aeration in rice canopy and induced serious pest . As a result, we indicated the nice rice population should increase the number of ST as high as possible and decreased the number of FT and BET as less as possible.3. The amount of N-uptake by rice was primarily affected by the amount of BT . The average weight of the individual had no significant difference among the treatments with different nitrogen level, and the N-uptake increased primarily depended on tillers increased. The more nitrogen was applied, the nitrogen contain of plant was higher and the more tillers was dying after n-2 stage resulting from the mechanism of population auto-regulation . The suitable percentage of the rice N-uptake should be above 45% in the period from n-2 to heading stage (HS). The relative rates of population absorbing nitrogen(RRA) of all treatments decreased with the development of rice , the greater ratio of BT to TN applied, the more faster their declining speed became. When the amount of BT was increased , the uptake of nitrogen by rice before n-2 stage was increased significantly , By contrast with this , the uptake of nitrogen by rice was inhibited after n-2 stage , In high yield rice population, the amount of BT was at the optimal level, RRA decreased stably and reasonably, the N-uptake during its each stage was fit for the rhythm of population growth and development, nitrogen use efficiency and productivity of grains were improved coordinately .4.The population with high NUE had special physiology characteristic such as the nitrogen content of leaf distributed in a spatial order , the leaf color changed from yellow to heavy green in a reasonable rhythm . The nitrogen content of the different organ declined in sequence as leaf > panicle > culm and sheath, the NSC content of leaf in sequence as culm and sheath > panicle > leaf . The apparent transportation percentage of nitrogen and NSC were both low ,but NHI and HI were both high ; The enzyme of the carbon and nitrogen metabolism catalyzed relative reaction actively, while their activities subsided with the leaf location descending from the top stem , the roots were vigorously in physiology, the dry matter was produced more than that of treatments with low NUE, nitrogen use efficiency and productivity of grains were both high.5. BT had a definite influence on rice quality.The more BT and less PN relatively was applied , the lower the filling rate, the brown rate and the head milling rice rate were , the lower the crude protein content and the shorter the Gel. consistency were , the higher the amylose and lysine content were ; the more BT and PN relatively was applied, the lower the filling rate, the brown rate and the head milling rice rate were , the lowerthe amylose and lysine content were too , the lower the crude...
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