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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 ...
The leaf is an integral part of the stem system, and most leaves are flattened and have distinct upper and lower surfaces that differ in color, hairiness, the number of stomata (pores that intake and output gases), the amount and structure of epicuticular wax, and other features.
Photosynthesis depends on the diffusion of carbon dioxide (CO 2) from the air through the stomata into the mesophyll tissues. Oxygen (O 2), produced as a byproduct of photosynthesis, exits the plant via the stomata. When the stomata are open, water is lost by evaporation and must be replaced via the transpiration stream, with water taken up by ...
The plant cuticle is one of a series of innovations, together with stomata, xylem and phloem and intercellular spaces in stem and later leaf mesophyll tissue, that plants evolved more than 450 million years ago during the transition between life in water and life on land. [11]
The upper angle between one part of a plant and another, e.g. the stem and a leaf. axile On an axis; of a placenta, on the central axis of the ovary. axillary Borne in or arising from the axil, usually referring to the axil of a leaf. axis The main stem of a whole plant or inflorescence; also, the line along which this stem extends.
Bulbs are a combination of stem and leaves so may better be considered as leaves because the leaves make up the greater part. Caespitose: When stems grow in a tangled mass or clump or in low growing mats. Cladode (including phylloclade): A flattened stem that appears leaf-like and is specialized for photosynthesis, [4] e.g. cactus pads.
Cladode – a flattened stem that performs the function of a leaf; an example is the pad of the opuntia cactus. Cladophyll – a flattened stem that is leaf-like and green – used for photosynthesis. Normally such plants have no, or greatly reduced, leaves. Climbing – typically long stems that cling to other objects.