| This study was carried out in glasshouse and organic nutrition lab affiliated to Resource Science department in Huajiachi Campus, Zhejiang University in Huajiachi Campus, Zhejiang University. Using normal aquatic culture method and partially sterile culture method, the effects of organic nitrogen (N^NOs) and organic nitrogen (Gly) on the growth, physiological change and the characteristics of amino acids secretied by roots of rice grown under drought stressful conditions were studied. Moreover, comparative studies between wholly sterile culture method and partially sterile culture method which could be used in the research of rice organic nutrition were also conducted. The results were as follows:1. Growth and physiological adaptation of different rice varieties stressed by drought1) After drought stress, shoot fresh weight, shoot dry weight, root fresh weight and root dry weight of Brazilian upland rice increased significantly, but fresh weight and dry weight of normal rice shoots and roots decreased mostly. Drought stress depressed plant height and root length of both Brazilian upland rice and normal rice varieties, but the depression of drought stress on Brazilian upland rice was more gently. The changes of chlorophyll content in the leaves of both Brazilian upland rice and normal rice varieties after drought stress were not obvious. After drought stress, the root to shoot ratio(R/S) of Brazilian upland rice varieties increased significantly, the rising extent was 28.8%, but the root to shoot ratio(R/S) of normalrice varieties changed few. It suggested that shoot growth was restrained more severely than root growth when both Brazilian upland rice and normal rice varieties were stressed by drought, moreover, compared with normal rice varieties, Brazilian upland rice was depressed less by drought.2) After drought stress, organic osmotica in the leaves of both Brazilian upland rice and normal rice varieties increased consistently, and the rising extent of soluble sugars(SS), free Proline, total free amino acid(TFA) and Pro/TFA ratio in the leaves of Brazilian upland rice reached to 70%, 180%, 70% and 59% respectively, which were significantly higher than those in the leaves of normal rice varieties, but there were no significant differences among the rising extent of the corresponding index in the leaves of individual normal rice varieties.3) The activities of POD, CAT in the leaves of both Brazilian upland rice and normal rice varieties increased consistently, and the rising extent reached to 80% and 76% individually. Morover, the activities and the rising extent of POD and CAT in the leaves of Brazilian upland rice were significantly higher than those in the leaves of normal rice varieties, which suggested that relatively higher ability of antioxidation promoted by enzymes were found in Brazilian upland rice which belongs to drought resistant rice varieties.4) The effects of drought stress on the content of nitrogen, phosphorus and potassium varied with rice varieties and the position of shoot and root of rice. As Brazilian upland rice was concerned, drought stress had no significant effect on nitrogen content and potassium content in the shoot and root and phosphorus content in the shoot but promoted phosphorus accumulation in the root. But the contents of nitrogen, phosphorus and potassium in the shoots and roots of normal rice varieties decreased significantly after drought stress.2. Effects of nitrogen nutrition level on growth and drought resistant physiology of rice.1) Drought stress decreased plant height, shoot dry weight, main root length and root dry weight of rice supplied with 160mg/L nitrogen. With no nitrogen supplied, shoot growth was restrained but root growth was promoted. But shoot and root of rice supplied with 40mg/L nitrogen was less restrained or remained growing. So it is important enough to supply suitable nitrogen nutrition for rice growth and drought resisting.2) After drought stress, the activity of POD enzyme changed little but the activity o...
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