Transport in Plants Test - 8

In plants capillarity is aided by the small diameter of the tracheary elements – the tracheids and vessel elements.

Surface Tension is the physical property of the water due to which molecules of water are attracted to each other in liquid phase more than to water in gas phase.

As various ions from the soil are actively transported into the vascular tissues of the roots, water follows (its potential gradient) and increases the pressure inside the xylem. This positive pressure is called rootpressure, and can be responsible for pushing up water to small heights.

Generally the concentration of minerals and its components found in soil solution is far below the levels of the same found in the cell sap. It means that the absorption of ions takes place against concentration gradient. The relative concentration of ions found in the cell sap and soil solution gives absorption ratio.

An important aspect that needs to be considered is the direction of transport organic and mineral nutrients however, undergo multidirectional transport.

Solute potential of a solution is always less than 0 as solute potential of distilled water is 0 and addition of solute decrease the solute potential.

Reverse osmosis is the movement of pure water form a solution through a semi permeable membrane under the influence of pressure higher than the osmotic pressure. This process is used to obtain drinking water from salty water.

Closing of stomata depends on increases CO₂ concentration in and around guard cell due to release of CO₂ in respiration combined with the absence of photosynthetic activity in dark. Closure of stomata cause decrease in transpiration.

In phloem transportation takes place in both direction from leaves to other part of plant or from lower to higher parts of plants. So, transport in phloem is bidirectional.

There are 8 types of aquaporins recorded. Aquaporinsare transport protein that rotate and release the molecules inside the cell. They are also called as water channels.