【摘要】 本文重点观察白皮松(Pinus bungeana)次生韧皮部中蛋白细胞不同发育时期的超微结构。白皮松次生韧皮部由筛胞、轴向薄壁组织、径向片和射线组成。大多数直立射线细胞与径向片薄壁细胞是蛋白细胞,虽然这两类蛋白细胞在形状和分布上有所不同,但它们都具有下列的细胞学特征:细胞质浓厚,线粒体丰富,具核糖体,粗糙内质网和大的细胞核;细胞核常呈凹陷形;蛋白细胞含有淀粉粒,但与其它的韧皮部薄壁细胞相比,蛋白细胞的淀粉含量较少。上述细胞结构特征显示出蛋白细胞具有旺盛的生理活性。蛋白细胞与其它薄壁细胞的主要区别是:蛋白细胞与相邻的筛胞以单侧筛域相联系,当筛胞死亡时也一同死去。更多还原

【Abstract】 This paper emphatically deals with the ultrastructure of albuminous cells in different stages of development in the secondary phloem of Pinus bungeana.The secondary phloem of Pinus bungeana is composed of sieve cells,axial parenchyma cells,radial plates and rays.Among the constituents,most of upright ray cells and radial plate parenchyma cells are albuminous cells.Although the shape and distribution of this kind of albuminous cells may be diffe- rent,they possess the following common cytological characteristics.These cells have dense cytoplasm with abundant mitochondria,ribosomes,rough eadoplasmic reticula and a large nucleus,the nuclei of some albuminous cells are lobed in shape which increases the outer sur- face of the nuclei.Usually the albuminous cell contains some starch granules,the quantity of the starch granules in albuminous cells is less than the other parenchyrma cells of the secondary phloem.All these cytological characteristics suggest that albuminous cells are active physiologi- cally.The distinguishing characteristics of albuminous cells from other parenchyma cells are that the albuminous cells are associated with sieve cells through unilateral sieve area and they died together with the sieve cells.更多还原