Which physiological process is primarily regulated by ethylene in plants?

Ethylene is a plant hormone that plays a crucial role in regulating several physiological processes, with fruit ripening and flower wilting being two of its most significant functions. Ethylene acts as a signaling molecule that triggers the complex biochemical pathways associated with ripening. When fruits mature, ethylene production increases, leading to changes that soften the fruit, alter color, and develop flavor, all of which are characteristics of ripening.

Additionally, ethylene influences flower wilting by promoting senescence, which is the process leading to the aging and deterioration of plant tissues. This regulation is important for the lifecycle of the plant, allowing for timely completion of reproductive phases and ensuring that energy resources are allocated efficiently.

Other processes listed, such as photosynthesis efficiency, water absorption, and root growth direction, are influenced by different hormones and environmental factors rather than being primarily regulated by ethylene. Therefore, the link between ethylene and its role in fruit ripening and flower wilting highlights its importance in plant growth and development.