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Photosynthesis, plant water transport and gas exchange are regulated by stomatal function which is important in the functioning of plants. [30] Stomata are responsive to light with blue light being almost 10 times as effective as red light in causing stomatal response.
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 ...
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).
As a consequence of these important functions, differentiation of cells to form stomata is also subject to environmental conditions to a much greater degree than other epidermal cell types. Stomata are pores in the plant epidermis that are surrounded by two guard cells, which control the opening and closing of the aperture.
Other plants show "inducible CAM", in which they are able to switch between using either the C 3 or C 4 mechanism and CAM depending on environmental conditions. Another group of plants employ "CAM-cycling", in which their stomata do not open at night; the plants instead recycle CO 2 produced by respiration as well as storing some CO 2 during ...
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]
A germination rate experiment. Plant physiology is a subdiscipline of botany concerned with the functioning, or physiology, of plants. [1]Plant physiologists study fundamental processes of plants, such as photosynthesis, respiration, plant nutrition, plant hormone functions, tropisms, nastic movements, photoperiodism, photomorphogenesis, circadian rhythms, environmental stress physiology, seed ...
However, in woody plants, while the respiratory function of stomata is retained in the living epidermis of leaves and green stems, that function is lost where the epidermis of trunks and branches is displaced by vascular and cork cambial activity and by secondary growth.