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不同供氮水平各生育时期甜菜叶片与根体氨同化酶谷氨酰胺合成酶(GS)、谷氨酸合酶(GOGAT)和谷氨酸脱氢酶(GDH)活性测定结果表明,甜菜体内存在GSGOGAT和GDH途径,但GS、GOGAT活性明显高于GDH,且两者变化趋势一致,说明GSGOGAT在甜菜体内氨同化中起重要作用,两者协同作用进行氨的同化。氨同化途径因供氮水平、生育时期及植株部位不同而异。高氮促进叶片GS、GOGAT活性提高,GDH活性降低,低氮GS,GOGAT活性较低,而刺激GDH活性。叶片氨同化酶活性高于根体,氨同化代谢旺盛。生育前期(137前)氨同化酶活性明显大于生育后期(258后),表明生育前期同化活跃,但GDH所起作用较小,而后期氮同化较弱,GDH发挥作用相对增大。
The results of the activity of glutamine synthetase (GS), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) of ammonia assimilate in beet leaves and roots at different growth stages showed that there was GSGOGAT and GDH, but GS and GOGAT activities were significantly higher than GDH, and the trend of the two changes was consistent, indicating that GSGOGAT plays an important role in the ammonia assimilation in beet, and the two act synergistically to assimilate ammonia. Ammonia assimilation pathway due to nitrogen levels, growth period and plant parts vary. High nitrogen promoted leaf GS, GOGAT activity increased, GDH activity decreased, low nitrogen GS, GOGAT activity lower, while stimulating GDH activity. Ammonia-assimilating enzyme activity higher than the root, ammonia assimilation metabolism exuberant. The activity of ammonia assimilation was significantly higher in the early stage of growth (before 137) than that in the late stage of growth (after 258), indicating that the assimilation was active during the early stage of reproduction, but the effect of GDH was less and the later stage of nitrogen assimilation was weaker.