Abstract:

A series of potted experiments were conducted with three rice cultivars (Lindao11,Shengdao13 and Yangguang200) to investigate the relationships between rates of fertilization and leaf nitrogen concentration (including 15N abundance and total nitrogen) . The results showed that leaf nitrogen concentration and 15N abundance wer sensitive to increased nitrogen supply. The relationships between leaf nitrogen concentrations and the rates of fertilization indicated that the 1st leaf total nitrogen concentrations significantly corelated with the rates of fertilization just at jointing stage. However 15N abundance of the 1st, 2nd and 3rd leaf were significantly correlated with the rates of fertilization at 0.01 level during whole growth stages. The nitrogen concentration were the highest at jointing stage,and those were the lowest at milky stage ,but nitrogen concentration differed among heading stage and booting stage not in a big way. 15N tracer method showed that the 15N abundance in lower leaf were higher than that in upper leaf at the low rates of fertilization and 15N abundance increased at high rates of fertilization at jointing stage. But nitrogen transferred to the fringe from the 1st leaf, as a result 15N abundance in upper leaf reduced at booting stage. With nitrogen’transfer from lower leaves to upper leaves at heading and milky stages, 15N abundance in lower leaf were distinctively less than in the upper leaf. The 15N abundance change can reflect the difference condition of fertilizer supply. The correlationship between 15N abundance and nitrogenous fertilizer quantity is better to show relations between nitrogenous fertilizer quantity and nitrogen nutrition.