Search results
Results from the WOW.Com Content Network
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 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]
Through photosynthesis, plants use CO 2 from the atmosphere, water from the ground, and energy from the sun to create sugars used for growth and fuel. [22] While using these sugars as fuel releases carbon back into the atmosphere (photorespiration), growth stores carbon in the physical structures of the plant (i.e. leaves, wood, or non-woody stems). [23]
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 CO 2 concentrating mechanism also maintains high gradients of CO 2 concentration across the stomatal pores. This means that C 4 plants have generally lower stomatal conductance, reduced water losses and have generally higher water-use efficiency. [2]
The rate of transpiration is controlled by the stomatal aperture, and these small pores open especially for photosynthesis. While there are exceptions to this (such as night or CAM photosynthesis), in general, a light supply will encourage open stomata. Temperature: Temperature affects the rate in two ways:
(Reuters) - U.S. homebuilder sentiment rose to a seven-month high in November and expectations for sales in the next six months surged to the highest in about two-and-a-half years after a ...
The stomatal pores are largest when water is freely available and the guard cells become turgid, and closed when water availability is critically low and the guard cells become flaccid. Photosynthesis depends on the diffusion of carbon dioxide (CO 2) from the air through the stomata into the mesophyll tissues.