Question

When the stem of a herbaceous plant of cut, water or sap oozes out, this is due to?
A. Guttation
B. Transpiration pull
C. Root pressure
D. Imbibition

Answer 1

Hint: Water is very much useful to both plants and animals. In plants, water is one of the main components in photosynthesis. Water has to be observed by plants and also the excess amount has to be released from plants. This mechanism is carried out by plants by many processes such as transpiration, ascent of sap, root pressure, guttation, imbibition and more.

Complete answer:
Guttation is a process where collection of water is seen as drops at the apex or tip of a leaves, guttation is the release of water from the body to maintain water levels within the plant body. This is mostly seen during night and it is not dew drops. Transpiration is a process where water is expelled from the leaves through stomata due to excess heat in the atmosphere and also maintain the temperature of the plant and also check the water levels which is absorbed from roots of the plant. Transpiration pull is a phenomenon where a water molecule is pulled out of the stomata as soon as it opens from the sun in day times. Transpiration pull cannot be seen in the stem when it is cut as they consist of a very low amount of stomata. Imbibition is a process where there is movement of water from a region of higher concentration to a region of lower concentration by solids such as seeds. This is not concerned with stem. Root pressure is the traverse osmotic pressure in the cells of root embedded in the soil which is contact with water, root is responsible in absorbing water and also for its movement within the plant through xylem, water entered through root moves to various parts of the plants due to pressure induced by the other water molecules which is been absorbed and helps in movement of water within the plant upwards.

Hence the correct answer is OPTION(C)

Note: Upward movement of water in plants is explained by a theory known as the ascent of sap. Water in the xylem continues to flow due to two major forces of attraction: adhesive force and cohesive force. Adhesive force is the force of attraction between the water molecules and the walls of xylem tissue whereas cohesive force is the force of attraction between neighbouring water molecules which can make water to flow continuously within the plant.