![]() ![]() Vertically elongated cells may be cylindrical and fusiform in form by the mutual pressure of contiguous cells, the latter often become prismatic. When the growth takes place chiefly in one direction, the cells become elongated, either horizontally or vertically. When growth takes place on all sides of the cell wall, but certain spots are more extensible than the rest, the internal pressure causes protrusions at those regions so that cells acquire a more or less regular star-like shape-such cells are called stellate. According to Matzke, most of the faces of the cell wall are pentagonal, but tetragonal and hexagonal faces can also be found. The basic shape of cells is a 14-faced polyhedron (Matzke, 1946), but plant cells with 12, 13, 15, 16 or more faces are also found. But under other circumstances, in consequence of the mutual pressure of the surrounding cells, they assume a polygonal form the number of the angles or faces depending upon the number and arrangement of the contiguous cells. In both the cases, the cells are almost or entirely free from external pressure. When the growth is more or less uniform in all parts of the cell wall, we get a spherical or rounded cell but when it is greater at the two extremities than at the sides, the form is elliptic or oblong. Cells become of various forms by irregularity of growth due to internal causes bringing about greater possibility of stretching. Cells may be spherical, oval or oblong, polygonal, star-like stellate, cylindrical, fusiform, elongated fibre-like etc.Īs the cells grow there is continuous formation of cellulose. Mature cells of multicellular higher plants vary greatly in size and shape-it has been found that the mechanical forces determine form of cells to some extent, but the function a cell performs is also another factor in the shaping process.
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