Question

Define : Root pressure / Transpiration pull / Cohesion / Vital theories.

Answer 1

$Root$ $pressure$ is a positive pressure which is responsible for the movement of ions and water into the root xylem and pushes it to a small height in the stem of plants. It is generated due to the osmotic pressure in the root cells when the soil moisture is high.

$Transpirational$ $pull$ is a biological process in the plants, in which the force of pulling is produced inside the xylem elements due to constant transpiration. It is transmitted down and finally transmitted to root, resulting in the upward movements of water.

$Cohesion$ is a molecular attraction among like molecules, such as the hydrogen bonding that occurs among molecules in water.

$Vital$ $theories$ are mostly based on the assumption that living cells play a vital role in pushing or pumping the water upwards.