蓝光对水稻幼苗碳水化合物和蛋白质代谢的调节

Effect of Blue Light on the Metabolism of Carbohydrate and Protein in Rice (Oryza Sativa L. ) Seedlings

分别以白光和黑暗处理为对照，蓝光处理１０ｄ的水稻幼苗碳水化合物含量下降，蛋白质含量增加，亚胺环已酮可抑制蓝光引起的蛋白质含量增加。蓝光处理的水稻幼苗总氨基酸含量比白光和黑暗处理分别提高１２％和３６％，游离态Ｇｌｕ、Ａｓｐ含量也比对照增加。蓝光处理促进水稻幼苗的呼吸作用，对丙酮酸激酶、硝酸还原酶、谷氨酰胺合成酶、谷氨酸合酶和转氨酶的活性表现出一致的促进效应。

Carbohydrate content in rice (Oryza sativa L. ) seedlings grown underblue light decreased, while nitrogenoussubstances accumulated. As comperedwith white light or dark treatment,content of all kinds of carbohydratesdecreased, and the decrease of starchwas most significant (Table 1 ). Bluelight promoted the increase of proteincontent (Fig. 1 ), which could be inhibited by cycloheximide (CHX )(Table 2). Rice seedlingS exposed toblue light had a greater amount of toealamino acids (hydrolysate of protein )than those exposed to white light or inthe dark (Fig. 2). Free glutamate andaspartute, which occupy central coitions in the metabolism of amino acids,were increased in rice seedlings treatedby blue light (Table 3).Blue light promoted the respiration of both etiolated and greenseedlings in which photosynthesis wasinhibited by DCMU (Fig. 3). The activity of pyruvate kinase was increasedby blue light (Fig. 4).At the same nitrate concentration(50 mmol/L), blue light was betterthan white light for nitrate reductaseinduction (Fig. 5 ). The activity ofglutamine synthetase (GS), glutalnatesynthase (GOGAT ), GOT and GPTwere increased in rice seedlings grownunder blue light (Fig. 6, 7).It is concluded that blue light canpromote the degradation of carbohydrate, which provides abundant carbonskeleton for amino acids Synthesis ; andcan also promote the assimilation of inorganic nitrogen, the formation of glutamate and glutumine, and transamination, eventually resulting in the enhancement of protein synthesis in riceseedlings.