What is the process by which plants lose water vapor called?

The process by which plants lose water vapor is called transpiration. This phenomenon occurs primarily through tiny openings in the leaves known as stomata. During transpiration, water absorbed by the roots is transported through the plant and eventually released into the atmosphere as water vapor. This process plays a critical role in regulating plant temperature, maintaining nutrient flow, and facilitating the movement of minerals from the soil to the plant. Transpiration also contributes to the water cycle, as the released water vapor eventually condenses and falls back to the earth as precipitation.

The other terms mentioned relate to different processes: absorption refers to the uptake of water and nutrients by plant roots, evaporation is the conversion of water from liquid to vapor, typically in non-biological contexts, and respiration involves the process through which plants (and animals) convert glucose and oxygen into energy, often producing carbon dioxide and water as by-products. None of these processes accurately describe the specific mechanism of water vapor loss from plants, making transpiration the correct term.