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3- Water moves from the xylem into the mesophyll cells, evaporates from their surfaces and leaves the plant by diffusion through the stomata. In plants, the transpiration stream is the uninterrupted stream of water and solutes which is taken up by the roots and transported via the xylem to the leaves where it evaporates into the air/ apoplast ...
Water-use efficiency is also a much studied trait in Plant ecology, where it has been used already in the early 20th century to study the ecological requirements of Herbaceous plants [12] or forest trees, [13] and is still used today, for example related to a drought-induced limitation of tree growth [14]
Different plant species can have different root pressures even in a similar environment; examples include up to 145 kPa in Vitis riparia but around zero in Celastrus orbiculatus. [13] The primary force that creates the capillary action movement of water upwards in plants is the adhesion between the water and the surface of the xylem conduits.
As a water molecule evaporates from the leaf's surface it pulls on the adjacent water molecule, creating a continuous water flow through the plant. [ 6 ] Two major factors influence the rate of water flow from the soil to the roots: the hydraulic conductivity of the soil and the magnitude of the pressure gradient through the soil.
Guttation is the exudation of drops of xylem and phloem sap on the tips or edges of leaves of some vascular plants, such as grasses, and also a number of fungi. Ancient Latin gutta means "a drop of fluid", whence modern botany formed the word guttation to designate that a plant exudes drops of fluid onto the outer surface of the plant, when the ...
Water potential is the potential energy of water per unit volume relative to pure water in reference conditions. Water potential quantifies the tendency of water to move from one area to another due to osmosis , gravity , mechanical pressure and matrix effects such as capillary action (which is caused by surface tension ).
Also, plants with deep reaching roots can transpire water more constantly, because those roots can pull more water into the plant and leaves. Another example is that conifer forests tend to have higher rates of evapotranspiration than deciduous broadleaf forests, particularly in the dormant winter and early spring seasons, because they are ...
The pressure flow hypothesis, also known as the mass flow hypothesis, is the best-supported theory to explain the movement of sap through the phloem of plants. [1] [2] It was proposed in 1930 by Ernst Münch, a German plant physiologist. [3]