Which of the following is a hormonal defoliant that increases ethylene synthesis?

Thidiazuron is specifically a hormonal defoliant that promotes the synthesis of ethylene, a plant hormone that plays a significant role in the abscission process, where leaves detach from plants. This compound is utilized in cotton production to effectively promote leaf drop, facilitating easier harvest by reducing the amount of foliage present during picking. The increased ethylene synthesis stimulated by thidiazuron accelerates the natural processes of leaf senescence and abscission, which is particularly beneficial in cotton production, where timely harvesting is crucial.

The other options listed do not influence ethylene production in the same way. Glyphosate is a non-selective herbicide that targets specific plant enzymes, and while it can cause stress that might indirectly influence plant hormones, it is not categorized as a hormonal defoliant. Chlorothalonil is a fungicide used to control fungal diseases and does not have any known role in ethylene production or defoliation. Acetamiprid is an insecticide belonging to the neonicotinoid class and its primary function is to control pest populations rather than impact hormonal processes related to leaf abscission. Thus, thidiazuron is distinctly recognized for its role in enhancing ethylene synthesis as a means to facilitate def