Effects of Various Nitrogen Applications on the Quality of the Progeny Seedlings in Rice

To explore the effects of nitrogen application on the protein content of rice seeds and the quality of its progeny seedlings, water culture was carried out and the physiological activities of the progeny seedlings in 5—13 days after the germination of the harvested seeds of the two common rice cultivars (japonica and indica) were measured. The rice plant was treated with various nitrogen applications at booting and tillering stages respectively. The principal results are as follows: (1) The protein content in caryopsis was the highest in the treatment with the higher application of nitrogen at booting stage than that at the tillering stage. (2)The increment of nitrogen application at booting stage had the positive effects on the height, fresh and dry weight of the seedlings, the chlorophyll content of the leaves, the photosynthetic rate, the content of soluble protein, the IAA content, amylase activities of the endosperm, the activities of CAT in leaves, and SOD in root tips. Meanwhile, their chilling resistance was enhanced compared with the seedlings without nitrogen supply. (3) The soluble sugar content was the highest in the seedlings with no nitrogen application, and the lowest in those with higher application of nitrogen at booting stage. So, the proper increase of nitrogen application at booting stage could be favorable to the growth of rice seedlings as well as the protein content in caryopsis.