Effects On Osmotic Adjustment And Key Enzyme In Nitrogen Metabolism Of Japonica Rice Varieties At Different Nitrogen Nutrition Levels

Rice is a staple food corp of Chinese, and nitrogen fertilizer application plays an important role on rice growth. The agricultural development of our country is relatively backward, and there are many scientific fertilizer application behaviors threaten the food security, so scientific fertilizer use had become increasingly urgent. This study samples for breeding of japonica rice varieties in recent years, by setting the 0 N, 0.5 N, N 1 and 1.5 N four nitrogen levels. To study the osmotic adjustment substances, Nitrogen metabolism activity of key enzyme, Nitrogen metabolism key enzyme genes expression Gln1;1 Gln1;2 and Nia2 and the change trend of total nitrogen content of different organs of Japonica rice varieties change trend, it provide the theoretical guidance for searching the suitable japonica rice nitrogen.Determination of Japonica rice leaves under different nitrogen levels were soluable protein, souble sugars, free amino acid, free proline and MDA. The change trend of souble sugars and free amino acid content of N levels show increased first, then the rise of the trend, soluble protein content of advancing with time after rising to decline, and the maximum value of content appeared in heading stage,free proline content was positively related with time. The content of MDA were positively correlated with N levels in heading stage. Leaves enzyme activity of GS and NR were positively correlated with N levels in heading stage,too.Gene expression quantity of Ji nongda809 leaves Gln1;1 and Gln1;2 had a high gene expression in maturing stage, the expression of 505 leaves were negative correlation with N levels in heading stage. The expression quantity of GS1 under different nitrogen levels and different varieties were significantly different.The expression of Nia2 were negative correlation with the enzyme activity of GS, then it was the largest expression at 1N level.Nitrogen content in different organs of early stage and end stage were more than other stages, most of them were positively correlated with N level,the content of nitrogen in each organs were positively correlated with N level. The content of nitrogen of 505 and 603 leaves showed the maximum were converge on 1.5N-1N and 1N-0.5N. From this discovery we know it is important for us to find a best N levels for each rice varieties.