What is transpiration?

• A. The loss of water vapor from plant surfaces, mainly through stomata.
• B. The process of photosynthesis using light energy.
• C. The uptake of minerals from soil by roots.
• D. The transport of sugars in the phloem.

Answer: (A)

Transpiration is the loss of water vapor from plant surfaces, mainly through stomata. Stomata are tiny openings on the leaf surface that control gas exchange. When they are open, water vapor escapes to the air, and this loss creates a pull that draws water up from the roots through the xylem by cohesion and tension. This movement of water helps transport minerals from the soil and also cools the leaf. The rate of transpiration depends on environmental conditions such as temperature, humidity, wind, and light, as well as how much water is available in the soil. This concept is distinct from photosynthesis (which uses light to make sugars), mineral uptake (root absorption of nutrients), and phloem transport (movement of sugars in the phloem).