白刺Nitraria sibirica Pall.胚胎学研究——4 果实和种子的发育解剖学

The Studies on the Embryology of Nitraria sibirica Pall. 4. The Developmental Anatomy of the Fruit and Seed

本文报道白刺果实和种子的发育解剖及其发育过程中淀粉的变化。白刺果实为复合核果。由三心皮合生的三室子房发育而来。三个子房室中有一室不产生胚珠,所形成的两个胚珠中仅一个最后形成种子,另一胚珠中途退化。果壁由外果皮。中果皮和内果皮组成。外果皮成熟时肉质可食;中果皮源于维管形成层,由纤维细胞构成。为成熟核果的果核部分;内果皮由约8层薄壁细胞构成,果实成熟时退化解体。种皮由内珠被、外珠被和最外层珠心细胞共同构成。胚珠在其发育过程中产生承珠盘和珠孔塞结构。

The developmental anatomy of the fruit and seed of Nitraria sibirica Pall. and the variation of the starch grain during the devlopment, are first reported in this paper. The fruit is a syncarpous drupe, that develops from a trilocular ovary that originally consists of three carpels. No ovule is permanently formed in one of the three ovary loculi, and only one of two ovules can ultimatly develop into seed, wheras another degenerates. The fruit wall can be seperated into three layers; exocarp, mesocarp, and endocarp. The exocarp con- sisting of an epidermis, a hypodermis and six or more layers of parenchyma cells, is edible as it matures. The mesocarp is composed mainly of xylary fibres developed from the vascular cambium activity, and forms the stone of the mature fruit. The endocarp consists of eight or more layers of non-compact parenchyma cells that disintegrate during the development of the fruit. The seed coat is formed together by the outer-integument, the inner-integument, and the outer-most-layer of nucllcar cells. During the development of the ovule, some chalazal nuclear cells devel-op into the hypostasc, and some inner-integument cells 'at micropylar end develop into the obturator.