Final answer:
Ethrel affects tomato ripening by releasing ethylene, which accelerates the natural ripening process, converting starch to sugar and changing the fruit's color. This method is used by commercial growers to control the timing of ripening, although such ripened tomatoes may lack the full flavor of those ripened on the vine.
Step-by-step explanation:
Ethrel, which releases ethylene, effectively influences tomato ripening by simulating the natural ripening process. Ethylene is a volatile plant hormone responsible for stimulating a series of reactions in the fruit which promote the conversion of starch and acids to sugars, increase in softness, and change in skin color due to the breakdown of green chlorophyll and synthesis of red lycopene and yellow carotene. These alterations enhance the overall palatability of the tomato and prepare it for consumption. Commercial fruit growers utilize this method to control the timing of ripening, allowing tomatoes to be picked while they are still green and less susceptible to bruising and then treated with ethylene to ripen before sale. However, it's worth noting that tomatoes ripened this way may not taste like vine-ripened tomatoes due to subtle differences in the ripening process.
Application of ethylene gas is commonplace in agricultural practices for controlling not only ripening but also for inhibiting leaf dropping in ornamental plants. In closed environments like greenhouses, the removal of ethylene using fans and ventilation is sometimes necessary to prevent premature wilting or falling of leaves. Ethylene's role extends beyond ripening; it also triggers leaf and fruit abscission, flower fading, and promotes germination in some plants