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In botany, a stoma (pl.: stomata, from Greek στόμα, "mouth"), also called a stomate (pl.: stomates), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange between the internal air spaces of the leaf and the atmosphere.
The leaf and stem epidermis is covered with pores called stomata (sing; stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The stomata complex regulates the exchange of gases and water vapor between the outside air and the ...
A hydathode is a type of pore, commonly found in vascular plants, [1] that secretes water through pores in the epidermis or leaf margin, typically at the tip of a marginal tooth or serration. Hydathodes occur in the leaves of submerged aquatic plants such as Ranunculus fluitans [ 2 ] as well as herbaceous plants of drier habitats such as ...
A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of gymnosperms and dicotyledonous flowering plants. [2] It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and ...
Drought tolerance of plants is mediated by several mechanisms that work together, including stabilizing and protecting the plant from damage caused by desiccation and also controlling how much water plants lose through the stomatal pores during drought. A plant hormone, abscisic acid (ABA), is produced in response to drought. A major type of ...
When water uptake by the roots is less than the water lost to the atmosphere by evaporation, plants close small pores called stomata to decrease water loss, which slows down nutrient uptake and decreases CO 2 absorption from the atmosphere limiting metabolic processes, photosynthesis, and growth. [2]
Their narrow pores are necessary in their function in most seedless vascular plants and gymnosperms which lack sieve-tube members and only have sieve cells to transport molecules. [1] While sieve cells have smaller sieve areas, they are still distributed across several cells to still effectively transport material to various tissue within the ...
The gating of an aquaporin is carried out by an interaction between a gating mechanism and the aquaporin, which causes a 3D change in the protein so that it blocks the pore and, thus, disallows the flow of water through the pore. In plants, there are at least two forms of aquaporin gating: gating by the dephosphorylation of certain serine ...