不同密度玉米种皮形态建成及胚乳淀粉粒超微结构差异

Investigations on Seed Coat Morphogenesis and Starch Granule Development in Maize Endosperm

试验以鲁单981为材料,研究了30000株/hm^2(低密度)和90000株/hm^2(高密度)种植密度下,玉米种皮的形态及胚乳淀粉粒超微结构。结果表明,随着子粒的发育,内珠被中的细胞质首先作为营养物质被吸收、解体,形成类似珠被绒毡层的黑层。黑层退化消失的同时,子房壁细胞也离散解体,最终使子房壁和内珠被愈合在一起形成种皮。授粉后10～15d是胚乳淀粉粒发育的质变时期;授粉后20～25d是淀粉粒发育的量变时期。高密度处理的种皮细胞总层数约占低密度处理的1/2,但其各层细胞中的内容物相对较多,种皮形态建成的速度较慢。授粉后10～20d,高密度处理的胚乳淀粉粒明显比低密度处理大且多;而授粉后25d表现相反。玉米胚乳淀粉粒的剖面面积多数集中在0.28～0.56μm^2,约占24.8%,剖面面积大于2.52μm^2的淀粉粒仅占5.2%。

In order dosperm, Ludan981 was dosperm in two planting to elucidate the developing disciplinarians of seed coat and starch granule in maize enused to study the morphogenesis of seed coat and development of starch granule in maize endensities, 30 000 plants/ha（lower density） and 90 000 plants/ha（higher density）. The results showed that the cytoplasm of inner-integument were absorbed and crushed firstly to develop into black layer, which is similar to integumentary tapetum. Companied with the degenerateness of black layer, the ovary wall cells dispersed and with the result that the ovary wall united with the inner-integument, referred to as seed capsule. The phase, from 10 to 15 days after pollination, was decisive for the qualitative changing of starch granule development but from 20 to 25 days after pollination was the critical phase of quantitative changing of that. The cell contents under higher density were more abundant and the morphogenesis speeds 10 to 20 days after pollination, the starch granules lower density but which was smaller and less at ranged from 0.28 to 0.56 μm^2, which account for of seed capsule were slower than those under lower density. under higher density were obvious larger and more than those under 25 days after ＇pollination. Most of the starch granule section area 24.80% of total starch granule. Only 5.2% of total starch granules that section area were higher than 2.52 μm^2.