Water use efficiency
Under water use efficiency (engl. Water-use efficiency, abbreviation WUE) is the ratio of fixed carbon to transpired water in plants. Plants fix carbon dioxide in the so-called dark reaction of photosynthesis . This CO 2 is absorbed through the opened stomata , but water vapor escapes. Plants in arid areas in particular therefore have to fix as much CO 2 as possible in a short time in order not to lose too much water. Such plants, e.g. B. C4 plants or plants with the Crassulaceae acid metabolism have a high water use efficiency.
Under drought stress ( water stress ), the induced abscisic acid closes the stomata in the leaves of the plants and the water use efficiency increases.
Depending on the determination of the water use efficiency, a distinction is made between:
- Water-use efficiency of productivity or integrated water-use efficiency: it is the ratio of biomass gained to water loss during biomass production.
- Photosynthetic of water-use efficiency: it is determined by gas exchange measurements. If it represents the ratio of the carbon obtained during photosynthesis to the water loss through transpiration, it is referred to as "instantaneous water-use efficiency". If the water vapor conductivity of the stomata is used instead of the transpiration rate, it is called "intrinsic water-use efficiency".
credentials
- ↑ B. Steuer, T. Stuhlfauth and HP Fock, The efficiency of water use in water stressed plants increased due to ABA induced stomatal closure, Photosynthesis Research 18: 327-336 (1988) doi: 10.1007 / BF00034837