长豇豆胚和胚乳的发育及营养物质积累

DEVELOPMENT OF EMBRYO AND ENDOSPERM AND NUTRIENT ACCUMULATION IN VIGNA SESQUIPEDALIS(L.)FRUWIRTH

长豇豆(Vigna sesquipedalis (L.)Fruwirth)开花前7—10小时传粉,开花后8—10小时完成双受精。合子期珠孔端及合点部位胚囊的周界壁有壁内突。胚发育属柳叶菜型。胚柄的基部细胞及基部区域外层细胞的外切向壁发生壁内突。成熟胚中胚柄宿存。开花后9—16天为子叶细胞中淀粉积累期,开花后12—18天为蛋白质积累期。胚乳发育为核型,珠孔端胚乳细胞化,合点端保持游离核状态。胚乳外层细胞为传递型细胞,珠孔端的胚乳细胞形成折叠细胞群,亦有壁内突。心形胚期胚乳开始退化解体,成熟胚期胚乳完全消失。

The structure of embryo sac,fertilization and development of embryo and endosperm in Vigina sesquipedalis(L.)Fruwirth were investigated.Pollization occures 7—10h before anthesis, and fertilization is completed 10 h after anthesis.After fertilization,wall ingrowths are for- med at the micropylar and chalazal ends of the embryo sac.Embryo development conforms to the Onagrad type,and passes through 2 or more celled proembryo,long stick-shaped,globular, heart shaped,torpedo,young embryo,growing and enlarging embryo and mature embryo. Wall ingrowths are formed on the walls of basal cells and outer walls of the cells at basal region of suspenser.The suspensor remains as the seed reaches maturity.The starch grains accumula- te in the cells of cotyledons by 9—16 days after anthesis,and proteins accumulate by 12—18 days after.The endosperm development follows the nuclear type.The endosperm cells form at the micropylar end,and remain free nuclear phase at chalazal end.The outer cells are trans- fer cells.Those cells at the micropylar end form folded cells with wall ingrowths.At heart- embryo stage,the endosperm begins to degenerate and disintegrates before the embryo matures.