transpirationssog

Transpirationssog, also called transpiration suction, is a term used in plant physiology to describe the suction force generated by the process of transpiration that pulls water from the soil into the plant and upward through the xylem. According to the cohesion-tension theory, evaporation of water from stomata creates negative pressure in the leaf's xylem, which propagates through the continuous water column, producing a tension that draws water from the soil. The magnitude of transpirationssog depends on transpiration rate, which is influenced by stomatal conductance, leaf area, temperature, humidity, and wind speed, as well as soil moisture and texture.

In practice, transpirationssog interacts with soil water potential and root system architecture to determine the rate and depth of water uptake. It can contribute to hydraulic lift and redistribution in some plant communities, and it is a key factor in plant drought responses. If the tension becomes too great, cavitation can occur, leading to embolism and reduced hydraulic conductivity.

Measurements of transpirationssog are indirect, often inferred from changes in soil moisture, sap flow, or leaf water potential, and are central to models of soil-plant-atmosphere water transfer. While the term is more common in German-language literature, its underlying concept is widely recognized in plant hydraulics. See also transpiration, water potential, and cohesion-tension theory.