利用光学显微镜和电子显微镜技术观察了大麦胚乳发育过程中贮藏蛋白的积累和蛋白体的形成。抽穗后8d的胚乳细胞,富含内质网和蛋白贮藏液泡(PSV),少量淀粉粒沿细胞核或细胞膜分布。贮藏蛋白颗粒在抽穗后10d的胚乳细胞中开始出现,内质网的腔膨大,积累贮藏蛋白,后脱离内质网形成蛋白体。在胚乳细胞生长分化早期,蛋白体呈球状进入PSV;随着胚乳发育,贮藏蛋白体急剧增多,以亚糊粉层细胞为主。在胚乳细胞生长分化中期,PSV充满蛋白体,其周围有电子致密物质;新产生的蛋白体在细胞质基质中呈球状聚集在一起。在胚乳细胞生长分化后期,PSV中的部分蛋白体或者细胞质基质中的部分蛋白体开始相互融合,同时内质网衍生出许多小蛋白体分散在淀粉粒之间。在胚乳发育成熟期,蛋白体相互融合形成无定形的蛋白质基质分布在淀粉粒间的间隙中。结果表明,大麦胚乳发育过程中,内质网衍生出蛋白体,聚集于PSV或细胞质基质中,然后相互融合形成成熟籽粒的蛋白质基质。
Storage proteins are accumulated during the development of barley (Hordeum vulgare L.) endosperm, and, as the source of protein and amino acids for seed germination, concentrated and packaged into protein bodies. The knowledge of the accumulation of storage protein and the formation of protein body is helpful for variety improvement in barley. In this study, using light and electron microscopy, the storage protein and protein body were observed from 6 to 28 days after heading (DAH), a period from the cellularization of endosperm to its desiccation. There were plenty of endoplasmic reticulum (ER) and protein storage vacuoles (PSVs) in the endosperm cells at 8 DAH with some starch granules around the cell nucleus or along cell membrane. Storage protein granules began to appear in endosperm cell at 10 DAH. Storage protein accumulated in the lumen of ER, then detached from ER and formed protein body. Protein bodies moved into PSV during the early stage of endosperm growth and differentiation. With the development of endosperm, storage protein granules quickly increased, especially in subaleurone cells. PSV was full of protein bodies with some electron-dense materials around PSV during the middle stage of endosperm growth and differentiation. Some newly formed protein bodies were spherical and aggregated in cell matrix. Some protein bodies in PSV or in cell matrix began to aggregate and coalesce, some small protein bodies derived from ER were dispersedly distributed among starch granules during the late stage of endosperm growth and differentiation. Individual protein body was no longer visible, but a protein matrix was confined in the space between starch granules during the mature stage of endosperm development. The results showed that storage protein was initially stored in individual protein body which was derived from the ER, distributed in PSV or cell matrix, and at last changed into protein matrix during caryopsis development.