羧甲基壳聚糖对玉米籽粒氮代谢关键酶和种子贮藏蛋白含量的影响

以羧甲基壳聚糖（ＮＣＭＣ） 处理玉米开花期果穗，发育中籽粒的谷氨酰胺合成酶（ＧＳ） 、谷氨酸脱氢酶（ＧＤＨ） 及谷丙转氨酶（ＧＰＴ） 活性均明显增强，而蛋白水解酶活性下降。羧甲基壳聚糖处理离体玉米籽粒酶提取液，酶液中ＧＤＨ 活性明显提高。羧甲基壳聚糖处理玉米果穗，其发育籽粒中可溶性蛋白和成熟种子中贮藏蛋白含量明显提高。这都表明，羧甲基壳聚糖对玉米氮代谢、蛋白质合成与积累具有明显的生理调节作用。

Effects of N Carboxymethylchitosan on N Metabolic Key Enzymes of Grains and Storage Protein Contents of Seeds in Maize

The effects of N carboxymethylchitosan on some of the important enzymes in nitrogen metabolism were studied by treating the ears of maize (Zea mays L.)with it at flowering stage. The activities of glutamine synthetase (GS), glutamate dehydrogenase (GDH), glutamic pyruvic transaminase (GPT) and proteolytic enzyme were determined at different time after the treatment,and the contents of soluble protein, storage protein and components of storage proteins were also examined after harvest. It was found that activities of GS (Fig.1), GDH (Fig.2), and GPT (Fig.3) in developing maize grains were increased remarkably by NCMC, which was also confirmed by in vitro enzyme reaction experiments(Fig.5), whereas proteolytic enzyme (Fig.4) activities were decreased. Meanwhile, it was found that the contents of soluble protein (Fig.6) in developing grains and storage protein in mature seeds (Table.1) were also increased remarkably. These results indicated that N carboxymethylchitosan has a significant physiological regulatory action on N metabolism and protein biosynthesis and accumulation in maize.