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本文在无氮的水培法中,设有~(15)N_2和~(15)N_3二个处理,8小时后,~(15)N_2处理的根瘤谷酰氨酸、丙氨酸、r—酪氨酸的~(15)N 浓度高;~(15)No_3处理的根部天冬酰胺最多。在茎部,~(15)N_2处理中尿囊素的~(15)N 浓度最高,说明根瘤中固定的氮素活跃地合成为尿囊素,并移向茎叶部。从根部向吸收的~(15)No_3的根瘤移动,在根瘤内~(15)N_3和~(15)No_3同样全部被同化,估计不同的移动形态是由于根瘤氮素代谢的特殊性。在生育期间同化的固氮量和吸氮量的分布中,认为根瘤和根部的氮素一半以上是由固氮素来的,明确了茎叶部的尿囊素大部来自根瘤,并通过茎的木质部移向地上部。在大豆根瘤中用~(15)N_2进行脉冲标记实验,认为固氮的最初产物氨的~(15)N 浓度提高最快数分钟内达到顶点,固定生成的氨是在谷酰氨合成酶/谷酰氨酸合成酶体系下开始同化的,根瘤中氮素主要移动形态是尿囊素。在根瘤中代谢循环快的氨基酸主要从谷酰氨酸的氨基转移反应中生成的。为了区别氮素代谢过程,用离心法分离根瘤至拟杆菌和细胞质两部分,认为拟杆菌部分含有多量氨,并最初被同化,细胞质部分含多量的尿囊素、天冬酰胺多。无氧条件下固定生成的氨的同化过程比自身回氮感受性要高。
In this study, the nitrogen-free hydroponics experiments were carried out with ~ (15) N_2 and ~ (15) N_3 treatments. After 8 hours, the glutamate, alanine, The concentration of ~ (15) N in tyrosine was high, while the number of asparagine in root of ~ (15) No_3 was the highest. In the stems, the concentration of ~ (15) N in allantoin was highest in ~ (15) N_2 treatment, indicating that the fixed nitrogen in nodules was actively synthesized into allantoin and moved to the stems and leaves. Nodules from ~ (15) No_3 uptaked from root to root nodule and ~ (15) N_3 and ~ (15) No_3 were also all assimilated in root nodules. It is estimated that the different movement patterns are due to the particularity of nodule nitrogen metabolism. In the distribution of nitrogen assimilation amount and nitrogen uptake assimilated during reproduction, it is considered that more than half of the nitrogen in root nodules and roots is made of nitrogen fixation. It is clear that most of the allantoin in stem and leaf parts comes from nodules and the xylem shift To the ground. In soybean nodules, pulsed labeling experiments with ~ (15) N_2 suggested that the concentration of ~ (15) N in ammonia, the initial product of nitrogen fixation, reached its peak within several minutes as fast as possible. The fixed ammonia produced was found in glutamine synthetase / Under the system of amylase synthase began to assimilate, the main movement form of nitrogen in nodules is allantoin. Amino acids that are metabolically fast in the nodules are mainly generated from the transamination of glutamate. In order to distinguish the nitrogen metabolism process, the nodule was separated by centrifugation into Bacteroides and cytoplasm. It was considered that the Bacteroides part contained a large amount of ammonia and was initially assimilated. The cytoplasm contained a large amount of allantoin and asparagine. Anaerobic conditions immobilized ammonia assimilation process than its own nitrogen sensitivity is higher.