银耳（Tremella　fuciformis）原基分化前期双核菌丝细胞和分生孢子的边缘体与质膜体

LOMASOMES AND PLASMALEMMASOMES OF DIKARYOTIC HYPHAE AND CONIDIUM IN THE PRECEDING FRUITBODY PRIMORDIA OF TREMELLA FUCIFORMIS

本文报道银耳（Ｔｒｅｍｅｌｌａｆｕｃｉｆｏｒｍｉｓ）原基分化前期．在双核菌丝的幼细胞、成熟细胞和分生孢子中，与质膜相关联的两类膜结构──边缘体和质膜体的形成与功能。根据相似结构的存在．支持小泡或多泡体排出质膜之外附在细胞壁上成为边缘体和参于细胞壁合成的假定。银耳原基分化前期．双核菌丝迅速分裂的幼细胞．其质膜内陷产生泡状质膜体，内含数个小泡，或产生膜状质膜体；在成熟细胞中．质膜内陷通常形成回旋的膜结构──膜状质膜体．内含１—２个电子致密小泡．当这两类质膜体脱离质膜进入细胞质后，有的膜层和小泡局部被消化．因此，推断质膜体具有内吞和输送养料的作用。另外．在桶孔隔膜闭塞一侧电子致密度高的细胞质中．还观察到一种罕见的只有单个膜层的质膜体．其内充满３个电子致密小泡．估计它的形成与功能同膜状质膜体相似。作者认为．桶孔闭塞和质膜体的出现是与银耳原基细胞分化有关联的两个重要特征。最后，在成熟细胞中，尚可以观察到质膜体的膜层能够散开形成内质网．因此．内质网也可以来源于质膜体。

This paper reports the structures and formation of both lomasomes and plasmalemmasomes in the dikaryotic hyphae and conidium of the preceding fruitbody primordia of Tremellafuciformis. Both lomasomes and plasmalemmasomes are a membranous structures associated with plasmalemma. The presence of similar structures supports that the hypothesis of themultivesicular bodies or vesicles pass through the plasmalemma embedded in the cell wall and become lomasomes, which take part in cell walls synthesis. In the growing young cells during rapid division and single conidium, depressions of the plasmalemma prepuce vesicular plasmalemmasomes containing some vesicles, but then it also may produce membranous plasmalemmasomes. In themature cells, invaginations of the plasmalemma generally produce membranous plasmalemmasomes Projecting into the cytoplasm, which composed of a convoluted framework of membranes continuous with the plasmalemma and one to two electron-dense vesicles. When these two type of plasmalemmasomes casted off from the plasmalemma to migrate cytoplasm, a pet of membrane lamellae and vesicles were digested. Consequently, it can be reasoned that the plasmalemmasomes are the result of endocytosis of the plasmalemma in order for cellular growth and differentiation to transport material from the. substrate into the organism. The electron-dense cytoplasm of the cell adjacent to the septal pore which was blocked by folded sheet of endoplasmic reticulum. The invagination of the plasmalemma produce rare pocket plasmalemmasomes projecting into thecytoplasm, which composed of a unit membrane and three electron-dense vesicles. The formation and function of the pocked plasmalemmasomes are similar to the membranous plasmalemmasomes. It is considered that blocked septal pore and present of plasmalemmasomes are two important characters, which concerned with primordial cellular differentiation of Tremella fuciformis.Finally, the membrane lamellae of the membranous plasmalemmasomes can be disengaged to become endoplasmic reticulum which have been observed in the mature cell. Thus the endoplasmic reticulum also may be derived flom Plasmalemmasomes.