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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.
Stroma (from Ancient Greek στρῶμα 'layer, bed, bed covering') is the part of a tissue or organ with a structural or connective role. It is made up of all the parts without specific functions of the organ - for example, connective tissue, blood vessels, ducts, etc.
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 N-terminus of the chlorophyll a-b binding protein extends into the stroma where it is involved with adhesion of granal membranes and photo-regulated by reversible phosphorylation of its threonine residues. [2] Both these processes are believed to mediate the distribution of excitation energy between photosystems I and II.
Stroma (tissue), the connective, functionally supportive framework of a biological cell, tissue, or organ (in contrast, the parenchyma is the functional aspect of a tissue) Stroma of ovary, a soft tissue, well supplied with blood, consisting of spindle-shaped cells with a small amount of connective tissue; Stroma of iris, fibres and cells in ...
Stomatal conductance, usually measured in mmol m −2 s −1 by a porometer, estimates the rate of gas exchange (i.e., carbon dioxide uptake) and transpiration (i.e., water loss as water vapor) through the leaf stomata as determined by the degree of stomatal aperture (and therefore the physical resistances to the movement of gases between the air and the interior of the leaf).
The cross-talk between the host stroma and tumor cells is essential for tumor growth and progression. Tumor stromal production exhibits similar qualities as normal wound repair such as new blood vessel formation, immune cell and fibroblast infiltration, and considerable remodeling of the extracellular matrix.
Early plants sucked water between the walls of their cells, then evolved the ability to control water loss (and CO 2 acquisition) through the use of stomata. Specialized water transport tissues soon evolved in the form of hydroids, tracheids, then secondary xylem, followed by an endodermis and ultimately vessels.