. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Gullliermond - Atkinson 14 Cytoplasm mic layer, or plasmalemma, in opposition to the rest of the cyto- plasm which is designated as endoplasm. This is the only mem- brane which exists in the Plasmodium of the Myxomycetes, in the Myxamoebae, as well as in various zoospores and spermatozoids of the algae and fungi. In other material, especially in the lower organisms, the equilibrium forms of the protoplasm when in the presence of water consist of lobes or pseudopodia, irregular and changing, blunt or spiny, perhaps in accor
. The cytoplasm of the plant cell. Plant cells and tissues; Protoplasm. Gullliermond - Atkinson 14 Cytoplasm mic layer, or plasmalemma, in opposition to the rest of the cyto- plasm which is designated as endoplasm. This is the only mem- brane which exists in the Plasmodium of the Myxomycetes, in the Myxamoebae, as well as in various zoospores and spermatozoids of the algae and fungi. In other material, especially in the lower organisms, the equilibrium forms of the protoplasm when in the presence of water consist of lobes or pseudopodia, irregular and changing, blunt or spiny, perhaps in accordance with temporary and local modifications of surface tension. There again everything goes on as if there were an elastic layer around the cytoplasm. Figure 8 represents the division into two tiny plasmodia of Vampyrella. The individuals in the process of separation remain for a long time united by a protoplasmic strand which becomes increasingly thin. Then suddenly it breaks in the middle and the. Fig. 8. — Division in Vampyrella. ps, pseudopodia. two points liberated by the rupture go back into the plasmodia to which they belong as if pulled back in by the contraction of an elastic membrane. In all other cells it is recognized that an anal- ogous membrane lines the cellulose wall. When a plant cell is plasmolyzed, for example an epidermal cell of Iris germanica, the cytoplasm leaves the cellulose wall and contracts in the middle of the cellular cavity to a perfectly delimited spherical mass as if it possessed a delicate external membrane. Following work by de Vries on the osmotic phenomena of plant cells, there was often given to the region of demarcation between the cytoplasm and the surrounding environment, the value of a differentiated membrane to which the semi-permeability of the cells has been attributed. In no case, however, can this membrane be detected morphologically by any kind of staining. Therefore its existence as a differentiated membrane is purely theoreti
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