The Observation And Research Of Pseudokeronopsis Aporubra By Electron Microscopy

In this paper, the pellicle, fiber system under the pellicle, oral organelle and someorganelles of Pseudokeronopsis aporubra were observed and researched by scanningelectron microscopy and transmission electron microscopy. Main results are as follows:(1) The pellicle is a three-layer film, consists of a outermost layer of cells and twomembranes of pellicular alveolus. The outer membrane of pellicular alveolus is close tothe plasmalemma. There is a larger interspace between the inner and outer membrane ofpellicular alveolus. The thickness of epiplasm, under the pellicular alveolus, is different.Some regions are reinforced by bundles microtubules about0.02μm in diameter. Someregions only have a thin layer. These microtubules can maintain the stability of cells.The pellicle isolates cell’s inside and outside environment but allows material exchangebetween intracellular and extracellular.(2) There are two types of fibers under the pellicle: one type is fine, about0.1μmin diameter; other type is about0.2μm in diameter. The two types of fibers should beintermediate filament. They woven each other as an whole organic structure. Theirfunction involves being a part of the cytoskeleton, supporting cells to maintain form,fixing organelles (mitochondrions, cell nucleus, cortical ganules) in the cytoplasm.(3) Two types of cortical ganules were observed by scanning electron microscopyand transmission electron microscopy. They are distributed irregularly under the cellpellicle. Some cortical granules, called typeⅠ, are spherical and vesicles, diameters areabout1.0μm. Type I cortical granules, filled with filamentous or flocculent material, arecolored particles and affect the colour of polypide. Other cortical ganules are calledtypeⅡ. Type II is blood-cell shap and colorless vesicle, about1.0μm in diameter, about0.4μm in height, with nothing in it. Their functions and the causes of their appearanceare still unclear. This article discused some problems about the origis and evolutionaryrelationships of cortical ganules in several species of Pseudokeronopsis.(4) A large number of mitochondrions were observed by transmission electronmicroscopy. Their length is about0.5~1.5μm and width is about0.2~0.5μm, internalcrest is tubular form. Mitochondrions distribute in active area of cell and provide energy for cell.(5) The oral organelle consists of EM, PM, PAM and cytopharynx. TEMcross-sections of cytopharynx middle part and cytopharynx end show that many radialvesicles arrange aroud cytopharynx. These vesicles maybe provided membrane forconstructing food bubble. Preliminary comparison of several kinds of oral organellesalso has been done.Above results enriched the study of this species and provided new basic data andinformation. Science values are significant in both morphological study of this speciesand biological study of this genus. Especially, the observation and study of corticalgranules will help to understand their structures and functions. Consequently, it willbring active effect on the evolution of the organelle, the plylogenetic relationshipsamong species, the classiflcation of cillates and the evolution of cillates.