Question

The process responsible for the movement of water from roots to all other parts of plants is
A. Evaporation of water from the leaves
B. Capillary action
C. Hydrophilic compounds
D. Active transport
E. Both A and B

Answer 1

Transportation of water, minerals, organic nutrients and plant growth regulators is essential in a flowering plant. Higher plants have specialised tissues for the conduction of these substances to each and every part of the plant body. Mainly these are of two types- xylem and phloem. The conduction of water and mineral salts upwards from the roots to stem and leaves occurs through xylem and the conduction of food material from the leaves to other parts of plants occurs through phloem

Complete answer:
As the roots absorb water, it has to move upwards against gravity to the higher parts of the plant. Xylem is responsible for this conduction movement of water up the plant. Aerial parts of a plant undergoes evaporative loss of water in the form of vapours. This process is called transpiration.
There occurs some specialised pore like structures on the green parts of plants (mainly leaves) that are responsible for the evaporative loss of water from the plants. These are called stomata. Stomatal transpiration is the major cause of water loss from the plant. As water evaporates through the stomata, since a thin film of water over the cells is continuous, it results in the pulling of water, molecule by molecule into the leaf from the xylem.
Due to this evaporative loss of water, a negative hydrostatic pressure is developed in the aerial parts of the plant. This is called a transpiration pull. Water is mainly pulled upwards in the plant through this transpiration pull. This upward pull depends on three major properties of water namely- cohesion, adhesion and surface tension.
The mutual attraction between water molecules is called cohesion and the attraction of water molecules to the surface of conducting tissue is called adhesion. This ability of water to rise in thin tubular conducting tissues (xylem) is called capillarity.
Thus the correct answer is option E.

Note: Apart from stomata, transpiration may also occur from cuticles on the epidermis of aerial parts (cuticular transpiration) and from minute pores called lenticels (lenticular transpiration). The transport of food occurs through the phloem from leaves to other parts of the plant. This transport occurs completely through an active pathway. Both loading and unloading of food material from leaves to other parts occurs against the concentration gradient through active transport.