Ethylene emission during ripening is associated with which change in fruits?

• A. Softening of the plant cell wall
• B. Dehydration
• C. Increase in chlorophyll synthesis
• D. Decrease in respiration rate

Answer: (A)

Ethylene acts as a ripening hormone and triggers texture changes in fruit by remodeling the cell wall. It signals enzymes such as polygalacturonase and pectin methylesterase to break down pectin and other wall polysaccharides in the middle lamella, weakening the connections between cells. This loosening and eventual separation of cells leads to softening, a hallmark of ripening. For context, chlorophyll is typically degraded during ripening, not synthesized, so color changes reflect pigment breakdown rather than increased chlorophyll. Also, respiration often rises during climacteric ripening, not decreases, which contrasts with the option about lower respiration. Dehydration isn’t the defining ethylene-driven change in ripening.