Search

Protoplasmic streaming was investigated in several types of cells from Chara braunii, and the data were subjected to extensive theoretical analysis. The following results were obtained: 1. Streaming velocity is relatively insensitive to cell length if the length/diameter ratio of the cell exceeds five. 2. Most of the viscous loss engendered in the bulk endoplasm and sap is localized near the indifferent lines. 3. The streaming velocity of the bulk endoplasm is directly proportional to the square root of the cellular diameter, and the power input per unit area to the bulk endoplasm is-over a wide range of velocities-independent of velocity. 4. The streaming velocity varies linearly with the temperature, and it is in principle possible to use this variation to determine the temperature variations of both the power input to the bulk endoplasm and an effective viscosity for this endoplasm. Finally, the function of the streaming is considered and several possibilities are discussed. [ABSTRACT FROM AUTHOR]

The role and distribution of the Golgi apparatus has been compared in hymenial and subhymenial cells of Coprinus cinereus using conventional electron microscopic and carbohydrate localization techniques. Basidia at early interphase II of meiosis possessed numerous single Golgi cisternae. Golgi vesicles may contain fibrous granular material similar to basidial and basidiospore walls. Vesicles similar in size and apparently in content to those on cisternae accumulated at the growing apex of the young basidiospore. Golgi vesicles were also found in cystidia but appeared to be absent in other cells studied. Pseudoparaphyses, cystidia and subhymenial cells contained large deposits of glycogen which were removed enzymatically in light microscope preparations, but carbohydrate staining persisted in the cytoplasm of basidia, cystidia and basidiospores at the probably sites of Golgi vesicles and cisternae after enzymatic digestion. Septal pore caps of subhymenial cells were surrounded by a fibrillar cytoplasmic zone devoid of cell organelles except ribosomes. The periodic acid-silver hexamine and silver protein techniques for ultrastructural localization of carbohydrates were compared; the latter gave specific results with the controls used. Carbohydrates were localized in certain wall layers of the immature basidiospore and in the contents of Golgi vesicles. Staining also occurred in glycogen, plasma membrane and lomasomes. In the septal pore apparatus staining occurred only in the septal wall and a region in the septal pore swelling probably containing fibrils. The wall of the pseudoparaphyses stained more than the basidial wall. The results suggest that carbohydrates accumulate in Golgi vesicles attached to cisternae, that changes in vesicle contents occur during migration to the basidiospore, and that these vesicles may transport polysaccharides and mucopolysaccharides to the developing basidiospore wall. [ABSTRACT FROM AUTHOR]

The equation for the calculation of the absolute water permeability constant, K ( Stadelmann 1963), by the plasmometric method, was demonstrated to be valid. A computer analysis of theoretically determined protoplast length vs. time diagrams indicated that the most accurate water permeability values for the Allium cepa bulb epidermis cells examined were found in the central part of the deplasmolysis curve. Here, interference of factors other than purely osmotic forces are least: e.g., for cells with equilibrium times of over 14 minutes, L should be taken between 160-300 seconds after initiation of deplasmolysis, and L between 40-200 seconds. With cells deplasmolyzing more slowly, the L values can be chosen nearer initiation of deplasmolysis. The L values can also be expressed in terms of protoplast length, L, and protoplast expansion, L. The latter form is more convenient since the values can be easily read from the deplasmolysis curve: Lapproximately between 60-90% L and L between 20-70% L. Adherence to strictly defined numerical limits for the 'optimal section' of the deplasmolysis curve is not as important as the recognition that a greater chance for erroneous calculation of K exists when L values are taken either at the onset of deplasmolysis, or near its conclusion. [ABSTRACT FROM AUTHOR]

Copyright of Computing is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computing is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Computing is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)