叶籽银杏叶生胚珠的发育组织化学研究

Studies on Histochemistry of the Developmental Epiphyllous Ovule in Ginkgo biloba var. epiphylla

采用树脂半薄切片技术对叶籽银杏叶生胚珠生长发育各阶段进行观察及组织化学分析。结果表明:(1)叶生胚珠发端期在叶片上表现为"突起"状态,其结构主要为维管束、薄壁细胞和分泌腔;其内中央淀粉粒少,与叶缘结合处淀粉粒多,淀粉粒小且沿细胞壁分布。(2)叶生胚珠雌配子体的发育经历了游离核阶段和细胞化阶段;游离核阶段雌配子体呈液体状态;细胞化初期,雌配子体内是大的薄壁细胞,无淀粉粒、脂肪和蛋白质的分布;随后淀粉粒渐多;细胞化后期淀粉粒进一步增多,变大,且有黑色脂滴在细胞壁附近。(3)胚乳发育阶段,细胞中积累淀粉粒,蛋白质增多,营养物质中心密集,边缘稀疏。(4)雌配子体游离核阶段开始有外珠被和中珠被的分化;7月上旬叶生胚珠出现明显的内珠被。(5)中珠被与内珠被间中隐线上方有一"锥状"结构,外珠被和中珠被间有较多的淀粉粒。

Observation and histochemistry analysis were taken on all stages of epiphyllous ovule in Ginkgo biloba var. epiphylla development using resin semi-thin section technique. The results showed that：（1）The epiphyllous ovule apparent＂gibbosity＂at the stage of origin,its main construction were vascular bundle,parenchyma cells,and cavities;In the center of the＂gibbosity＂,there were a few starch grains,but a lot of starch grains were in the junction of＂gibbosity＂with leaf and distributed along the cell wall. （2）The development of epiphyllous ovule female gametophyte experienced free nuclei stage and cell wall formation stage;At free nuclei stage,the female gametophyte was liquid;At early cell wall formation stage,it was constituted by many big parenchyma cells,and there were no starch grains,lipid droplet and protein in them;Later,the starch grains became more;At the late wall formation stage of female gametophyte,the starch grains became more and bigger,and there was black lipid droplet surrounded cell wall. （3）At the stage of endosperm development,the cells accumulated starch grains and protein. The distribution of nutrients was centre-intensive,sparse-edge.（4）The differentiation of outer integument and meso-integument began at early free nuclei stage of female gametophyte;At the beginning of July,the inner integument appeared. （5）Between the meso-integument and inner integument,which was above the middle line,there was a＂conoid＂structure;Between the outer integument and meso-integument there were plenty starch grains.