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The placenta of the anthocerote, Dendroceros tubercularis Hatt., consists of long and branched haustorial cells, that arise from the foot and gametophyte transfer cells. Both cell types contain electron-dense vacuolar deposits that were digested by pronase and therefore are assumed to be protein. These deposits were negative to the PATAg test for carbohydrates. Protein bodies were also found in the parenchyma cells of the foot and younger meristematic cells at the base of the capsule. Vacuolar deposits of osmiophilic material in the gametophyte cells external to the placenta were stained non-specifically with PATAg method and were not affected by pronase. The haustorial cells have pleomorphic plastids lacking starch and a thylakoid system, whereas the transfer cells have well developed chloroplasts. No pronase-sensitive material was detected in the apoplastic space separating gametophyte and sporophyte cells. These results suggest that protein is synthesized in the haustorial cells, perhaps from precursors provided by transfer cells, and is then transferred, via plasmodesmata, to the parenchyma cells of the foot and eventually to the cells of the growing capsule. [ABSTRACT FROM AUTHOR]

The gametophyte of Phaeoceros laevis Prosk. forms small parenchymatous tubers as perennating organs. The development of tuber cells is characterized by marked cytoplasmic proliferation. The chloroplasts are packed with starch and abundant lipid bodies (spherosomes) are produced in the cytoplasm in association with rough endoplasmic reticulum. The vacuoles become pleomorphic and accumulate electron-dense deposits. These were negative to PATAg staining for carbohydrates and were digested by pronase; therefore they are assumed to be protein. No ultrastructural evidence was found for the participation of either ER or dictyosomes in the biogenesis of the protein-storing vacuoles. The mature tubers have a distinct layer of epidermal cells with thick external walls, and frequently harbour intercellular cyanobacteria. [ABSTRACT FROM AUTHOR]

Stem chlorenchymatous cells from well-watered and water-stressed plants of Cissus quadrangularis L. were examined to evaluate the effect of drying on cell structure and metabolism. At a stem relative water content as low as 52-58%, cellular integrity was maintained, but some qualitative alterations occurred. Chlorophyll coment was higher in stressed plants, and the intact photosynthetic apparatus exhibited an increased degree of thylakoid stacking paralleled by a lower chlorophyll a/b ratio. Overnight malate accumulation was very low. Starch was retained but its day/night fluctuation was practically suppressed. Plastosomes were smaller and fewer, and the range of their daily fluctuation was very reduced. Vacuoles underwent fragmentaion and accumulated osmiophilic deposits. The maintenance of the cellular integrity accounts for the ability of C. quadrangularis to recover rapidly from water stress. [ABSTRACT FROM AUTHOR]

Vegetative cells of the gametophyte phase of the moss Timmiella barbuloides (Pottiales) are characterized by large cytoplasmic bodies of spherical shape (SBs) whose ribonucleoprotein composition is cytochemically demonstrated. SBs seem to be derived from massive aggregation of cytoplasmic ribosomes, with possible participation by rough endoplasmic reticulum elements. SBs have been found in stereids, parenchymatous cells and young hydroids of the gametophyte stem, and in euricysts of the leaf nerve. The SBs develop early in the course of cell differentiation and, once formed, persist until advanced stages of cell senescence. [ABSTRACT FROM AUTHOR]