羊草(Leymus chinensis)胚乳发育及颖果发育过程中多糖的动态

本文应用石腊切片法和组织化学方法对羊草的胚乳发育以及颖果发育过程中淀粉的累积和动态进行了研究。结论如下,羊草的胚乳发育为核型。游离核分裂的方式为有丝分裂和无丝分裂两种。椭圆形胚期,胚乳开始细胞化,细胞化顺序从珠孔端到合点端。首先游离核之间出现成膜体,经细胞板产生初始垂周璧,经过一段“开放细胞”时期,以后形成平周壁。羊草胚乳细胞增生无形成层状结构存在,各层细胞均可分裂。在珠孔端的胚乳细胞中见到核穿壁现象。子房壁内淀粉的积累从胚囊成熟期开始增长,到二细胞原胚期达到最高峰,以后随胚乳淀粉的积累而下降。最后胚成熟时子房壁组织解体。中央细胞中不含淀粉,受精后初生胚乳核周围出现大量淀粉,游离核时期淀粉消失,单层细胞的胚乳内淀粉重新出现,以后淀粉含量迅速上升。珠心、珠被、反足细胞都不含淀粉。宿存助细胞具丰富的淀粉。

Endosperm Development and Change of Polysaecharide During the Caryopsis Development in Leymus chinensis

The endosperm development follows the nuclear pattern. The formation of endosperm cell begins at the micropylar end of the embryo sac when the embryo is elliptical. Due to the formation of anticlinal wall,a layer of free nuclei becomes a layer of"open cells"which lack the inner periclinal wall ,then the inner peri- clinal wail forms. The phragmoplast appears among the free nuclei in the anaphase of mitosis. The initial an- ticlinal wall arises from the cell plate. The overy wail starch diposition increases during the stage of embryo sac maturation, At 2-celled proembryo stage,the starch content of the ovary wall is at the maximum, with the development of endosperm the starch content declines,when the mature caryopsis forms the ovary wall tissue collapses. There is no starch in the central cell. The starch appears around the primary endosperm nu- cleus,and disappears at free nuclear stage. When the endosperm cell forms starch appears again,then it in- creases rapidly. There is no starch in the nucellus,integuments and the antipodal cells, the persistent synergid contains a large amount of starch.