Question

The process by which plants lose water by evaporation is called
(a)Respiration
(b)Photosynthesis
(c)Transpiration
(d)Absorption

Answer 1

Hint: It is the process of water movement by plant and evaporation from aerial parts like leaves, flowers, and stem. Plants regulate this process by controlling the size of stomatal apertures.

Complete answer:
The process by which plants lose water by evaporation is called Transpiration. Transpiration is the loss of water by plants through evaporation. It mainly occurs through the stomata in the leaves. Water is transient in plants. In photosynthesis and plant growth, less than one percent of the water reaching the leaves is used and most of it is lost through the stomata during transpiration.

Transpiration has more than one purpose:
-It creates a transpiration pull for absorption and transport.
-Supplies water for photosynthesis.
-It transports the minerals from the soil to all parts of the plant.
-Cool the leaf’s surface, sometimes 10-15 degrees, by evaporative cooling.
-It keeps cells turgid and maintains the shape and structure of the plants.

Transpirational pull depends on the following factors of water -
> Cohesion: Mutual attraction between water molecules.
> Adhesion: Attraction of water molecules to polar surfaces.
> Surface tension: Water molecules are more attracted to each other in the liquid phase than in the gaseous phase.

So, the answer is ‘Transpiration’.

Notes:
-Guttation is the loss of water in the form of water droplets from hydathodes (small pores) on the leaf margin of a small herbaceous plant.
-Cohesion tension transpiration pull model explains the transport of water through the xylem.
-C4 plants lose only half as much water as C3 plants for the same amount of fixed carbon dioxide, due to their evolved anatomy.
-A mustard plant absorbs water equal to its weight in about just 5 hours and a mature corn plant absorbs 3L of water per day.