小麦籽粒发育过程游离氨基酸的变化

Changes of Free Amino Acid in Developing Grain of Wheat

小麦籽粒游离氨基酸的百分含量在开花后4～12天急剧增加;然后又迅速下降直到成熟。以籽粒为单位表示的各氨基酸含量均在开花后16～32天处于较高水平。丙氨酸、谷氨酸和丝氨酸是游离氨基酸库的主要组分,脯氨酸在开花后8～12天增长较多,甘氨酸从16天后有明显增加,其余氨基酸变化不大。结果表明,小麦籽粒游离氨基酸含量随着组分的变更而变化,不同氨基酸在籽粒发育的不同时期达到一个最高值。这些占优势的游离氨基酸可能为蛋白质合成所需的其它氨基酸的代谢提供氮源。

The free amino acid content in developing wheat grain increased rapidly 4~12 days after anthesis, and then decreased rapidly until maturity. The free amino acid content per grain maintained a high level in 16~32 days after anthesis. Alanine, glutamic acid and serine were main components in total free amino acid pool. Proline increased markedly 8~12 days after anthesis, glycine 16 days after anthesis, and the others did not vary much in the course of grain development, but results also revealed that the free amino acid content of developing grain varied with the changing of its composition, and different amino acid reached its highest level at differ ent time. Those amino acids with high content might be the source of nitrogen for the metabolism of other amino acids in protein synthesis.