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A plant cell wall was first observed and named (simply as a "wall") by Robert Hooke in 1665. [3] However, "the dead excrusion product of the living protoplast" was forgotten, for almost three centuries, being the subject of scientific interest mainly as a resource for industrial processing or in relation to animal or human health.
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
Collenchyma cells are usually living, and have only a thick primary cell wall [6] made up of cellulose and pectin. Cell wall thickness is strongly affected by mechanical stress upon the plant. The walls of collenchyma in shaken plants (to mimic the effects of wind etc.), may be 40–100% thicker than those not shaken.
Epidermal cells are tightly linked to each other and provide mechanical strength and protection to the plant. Particularly, wavy pavement cells are suggested to play a pivotal role in preventing or guiding cracks in the epidermis. [4] The walls of the epidermal cells of the above-ground parts of plants contain cutin, and are covered with a cuticle.
The cell wall consists of peptidoglycan in bacteria and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment. Some eukaryotic cells (plant cells and fungal cells) also have a cell wall.
Due to their active division and undifferentiated nature, meristematic cells form the foundation for the formation of new organs and the continuous expansion of the plant body throughout the plant's life cycle. Meristematic cells are small, with thin primary cell walls and small or no vacuoles.
The pit aperture is the opening at either end of the pit chamber. The pit membrane is the primary cell wall and middle lamella, or the membrane between adjacent cell walls, at the middle of the pit chamber. [2] The primary cell wall at the pit membrane may also have depressions similar to the pit depressions of the secondary layers.
Its most commonly noted function is the support through strengthening of wood (mainly composed of xylem cells and lignified sclerenchyma fibres) in vascular plants. [17] [18] [19] Finally, lignin also confers disease resistance by accumulating at the site of pathogen infiltration, making the plant cell less accessible to cell wall degradation. [20]