Does transpiration also occur in aquatic plants

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Transpiration of plants

[666]Transpiration of plants, the release of water through evaporation on its surface. Transpiration is primarily a physical process, the intensity of which depends on the one hand on the size of the evaporating surface and on the other hand on the heat, the moisture content of the air and its state of movement. The organization of the plant influences the process biologically, insofar as the surface is covered with a layer of cork or wax or with hair (see skin tissue), inhibiting or promoting the formation of adjustable stomata in connection with a ventilation system (see ventilation tissue) acts on the physical process. For the life phenomena of plants, transpiration is particularly important insofar as it provides an energy source for the movement of water and thus for the migration of substances in general (see Nutrition of Plants, p. 60). It also makes plants dependent on the roots' ability to absorb water from the soil. In water-poor soils, in cold, oxygen-poor swamp soils, in which the roots can only develop a small amount of sucking activity, only those plants are able to live in which transpiration is reduced to a minimum due to special organizational conditions. At locations with strongly fluctuating moisture content of the substrate, special water reservoirs (see storage tissue) are often formed on or in the plants that thrive there, from which the loss of perspiration during the dry season can be covered. Under conditions in which the intensity of the transpiration does not suffice for the movement of water in the plant body, in addition to the transpiration there is an excretion of liquid water, which is usually caused by special organs (hydathodes, see d.). The amount of water released from living plants through transpiration is more than 1 liter for a sun rose approx. 2 m high, for a free-standing, medium-sized birch with around 200,000 leaves, an average of 60–70 L., on a hot, dry day approx 400 L. daily. One hectare of beech forest gives off an average of 30,000 liters of water per day, a morning with cabbage plants evaporates 2 million liters, and one with hops 3–4 million liters of water. Cf. Burgerstein, The Transpiration of Plants (Jena 1904).