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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).
Since photosynthesis, transpiration and stomatal conductance are an integral part of basic plant physiology, estimates of these parameters can be used to investigate numerous aspects of plant biology. The plant-scientific community has generally accepted photosynthetic systems as reliable and accurate tools to assist research.
The overall 13 C fractionation for C3 photosynthesis ranges between -20 and -37‰. [2] The wide range of variation in delta values expressed in C3 plants is modulated by the stomatal conductance, or the rate of CO 2 entering, or water vapor exiting, the small pores in the epidermis of a leaf. [1]
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 primary function of kranz anatomy is to provide a site in which CO 2 can be concentrated around RuBisCO, thereby avoiding photorespiration. Mesophyll and bundle sheath cells are connected through numerous cytoplasmic sleeves called plasmodesmata whose permeability at leaf level is called bundle sheath conductance.
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.
Moisture stress is a form of abiotic stress that occurs when the moisture of plant tissues is reduced to suboptimal levels. Water stress occurs in response to atmospheric and soil water availability when the transpiration rate exceeds the rate of water uptake by the roots and cells lose turgor pressure.
The stomatal conductance g s accounts for the effect of leaf density (Leaf Area Index), water stress, and CO 2 concentration in the air, that is to say plant reaction to external factors. Different models exist to link the stomatal conductance to these vegetation characteristics, like the ones from P.G. Jarvis (1976) [4] or Jacobs et al. (1996 ...