Question

Guttation is mainly due to-
A-Root pressure
B-Osmosis
C-Transpiration
D-Imbibition

Answer 1

Hint:
Guttation, the process of secretion of water droplets from the edges/pores of some vascular plants like grass. Guttation is often confused with dew droplets that condense from the atmosphere onto the plant's surface; instead they are excess water present in the plant. A white crust remains on the leaf surface.

Complete answer:
Guttation is the process of loss of water from plants, mostly from margins of leaves.
It occurs when the rate of water absorption is higher than the rate of transpiration and soil is well watered. Due to this a positive root pressure is developed and water is pushed out through pores at vein endings of the leaf called hydathodes.
A group of loosely arranged achlorophyllous or colorless hydathode is made up of parenchymatous cells called epithem. These help in absorbing inorganic and organic solutes present in the exudate. Thus guttation occurs due to the positive pressure in the xylem developed due to the root pressure.

Hence, root pressure is the cause of guttation. So the correct option is (A).

Additional information-
Osmosis is defined as the tendency of the fluid to pass through a semipermeable membrane from a region of higher concentration to a lower concentration.
Transpiration is the process of removal of excess water from the aerial parts of the plant, it keeps the cell turgid and helps in the movement of minerals from the soil to parts of the plant.
Imbibition is the process of water adsorption by solid substances without forming a solution.

Note: Guttation occurs during night time. It is an uncontrolled phenomenon. In this, the plant’s root system absorbs extra water. Stomata are filled with water due to root pressure. When stomata offer no resistance, water is poured out through the pores. Guttation helps achieve the balance of water in a plant.