transpirational

Root pressure provides the impetus for this flow, rather than transpirational pull.

This phenomenon is important in transpirational pull in plants.

Numerous morphological adaptations are therefore situated around reducing transpirational water loss.

Maternal body contact increases at lower moisture levels potentially reducing transpirational loss of the eggs.

The main contributor to the movement of water and mineral nutrients upward in vascular plants is considered to be the transpirational pull.

Transpirational pull results from the evaporation of water from the surfaces of cells in the leaves.

Physical arguments, in particular transpirational pull and root pressure, have since been shown to be adequate for explaining the ascent of sap.

Movement of a chemical signal could be through the xylem, although this would require a reversal in the direction of transpirational water flow.

Then, transpirational cooling of leaves would decline and leaf temperature and transpiration rate per unit g would rise.

Transpirational pull requires that the vessels transporting the water are very small in diameter, otherwise cavitation would break the water column.

When transpiration is high, xylem sap is usually under tension, rather than under pressure, due to transpirational pull.

Further, in other settings water transport does occur via tension, most significantly in transpirational pull in the xylem of vascular plants.

Xylem transport is driven by a combination of transpirational pull from above and root pressure from below, which makes the interpretation of measurements more complicated.

Until recently, the differential pressure (suction) of transpirational pull could only be measured indirectly, by applying external pressure with a pressure bomb to counteract it.

Frequent hot northerly airflows also occur during January-March which have a strong desiccating effect on the alpine soils, placing the plants under transpirational stress.

Physiologist Von Mohl explored solute transport and the theory of water uptake by the roots using the concepts of cohesion, transpirational pull, capillarity and root pressure.

This capillary action has profound consequences for biological systems as it is part of one of the two driving mechanisms of the flow of water in plant xylem, the transpirational pull.

The velamen also serves a mechanical function, protecting the vascular tissues in the root cortex, shielding the root from transpirational water loss, and, in many cases, adhering the plant to the substrate.

In plants that exhibit hydraulic redistribution, there are xylem pathways from the taproots to the laterals, so the loss of water from the laterals creates a pressure potential analogous to that of transpirational pull.

Note that when the transpirational stress is low (for example humid days, or if you a plastic bag over a plant for instance) the exiting of water molecules from the leaves is lessened and the plant can operated under conditions of either lower root mass or less watering.