Question

Which of the following is not purpose of transpiration ?

• A. Supplies water for photosynthesis
• B. Maintains shape and structure of plants
• C. Helps in translocation of sugar from source to sink
• D. Cools leaf surfaces

Answer 1

Answer: (C)

Helps in translocation of sugar from source to sink

Answer 2

The loss of water in the vapour form from the exposed parts of a plant is called transpiration. Transpiration supplies water for photosynthesis. As water evaporates through the stomata, it results in pulling of water, molecule by molecule into the leaf from the xylem. This ascent of sap is helpful in transporting minerals from the soil to all parts of the plants. Transpiration maintains the shape and structure of plant parts by keeping cells turgid. Radiant heat falling on the plants increases their temperature which may be dangerous to the plants. Transpiration, cools leaf surfaces by evaporating water and lowering down their temperature by $10^{\circ} - 15^{\circ}C$. Mineral salts are mostly distributed by rising column of sap.