Information on Different Plant Cells
- Parenchyma cells control the size of plant stomata, basically the pores on the outer skin of plants. This regulates the amount of water loss and gas exchange (oxygen and carbon dioxide) in plants. These cells also aid in photosynthesis (the process of turning light into energy) and food storage.
- Sclerenchyma cells form important support structures in plants. These cells exist in two categories: sclereids and fibres. Sclereids are responsible for the hardness or sturdiness in plants. Sclereids, for example, cause the hardness in walnut shells and date seeds. Fibres store starch granules and are believed to play a role in water transport.
- The thick walls of these cells provide mechanical support for plants. The stalks of leaves usually are reinforced with collenchyma cells. These cells also are found in areas of plants that are growing rapidly and require extra support.
- Xylem and phloem are the areas in the plant through which essential nutrients and water are transported.
Xylem transports water and dissolved materials from the roots to all other parts of plants. Xylem cells actually die at maturity but provide the passageway through which water and minerals travel. Within the xylem are two types of conducting cells: tracheids and vessel elements. These cells provide rigid tunnels for transport from roots to stems to leaves. - Phloem transports absorbed organic matter in plants through sieve cells, albuminous cells, sieve tube members and companion cells. All phloem cells are alive at maturity because energy is needed for the physical transport of organic material. Sieve cells, present in ferns and conifers, have pores scattered across their surfaces, aiding in the absorption and transport of organic material. Albuminous cells are closely related and perform a similar function.
Sieve tube members, also called angiosperms, are present in flowering plants and are arranged end to end in tubes. These also aid in moving organic material throughout plants. Sieve tube members always work in conjunction with companion cells, which control the metabolism of cells.