Question

With an increase in temperature, the rate of transpiration becomes
A. Low
B. High
C. Low in herbs and high in trees
D. Immediately stops

Answer 1

Hint: The transpiration is the loss of water in the form of vapour through the stomatal opening of the plants. It helps to maintain the water level in plants and provide a cooling effect to the plant body.

Complete answer: The water travels in plant tissues via specialized tissues called the xylem. It involves a mechanism called the ascent of sap that helps in the upward movement of water and minerals from the soil to the upper part of the plant. Xylem is complex vascular tissues which support
water conduction in a plant. It is composed of both living and non-living tissues. The transpiration is influenced by environmental factors such as humidity and temperature. If the temperature of the environment is higher, then the transpiration increases and if the environmental temperature is low, the transpiration rate is also lower. Not only the temperature but also the wind and humidity influence the transpiration rate of a plant. If the humidity is high in the surrounding area, then the rate of the transpiration is low, but in the case of low humidity, the transpiration rate is high. The water moves from the lower tissue of the plant to the upper part of the plant via the transpiration pull. It causes loss of water from the mesophyll cell to intercellular spaces and the vapour moves out of the plant through stomata. The DPD of a mesophyll cell increases and these cells absorb water from adjacent cells and ultimately the water from the xylem elements of the vascular bundle of a leaf creates a tension of pull which causes upward movement of the water.
Hence, the correct answer is option B.

Note: Certain types of plants have specialized features that prevent high transpiration rate due to low availability of water, for example, some plants have their leaf modified into spines, some develop cuticle layers to prevent water loss by minimum surface area exposure. Some plants develop stress hormones to resist water loss.