Damaged Tannia leaves present yellowing and browning. The objective of this study was to evaluate the effect of physical damage on the postharvest metabolism of tannia leaves. Chlorophyll content and the accumulation of soluble phenolic compounds were evaluated in tannia leaf discs containing holes made with a needle in one leaf side, simulating the damage in the field and transport. The undamaged side was used as control treatment. To evaluate the ethylene and CO2 production, damaged and intact leaf discs were infiltrated with 1-aminocyclopropane-1-carboxilic acid (ACC) or deionized water. Intense degradation of chlorophyll occurred within the first 24 hours after harvest, but the damage did not stimulate the degradation of chlorophyll or ethylene production. The damaged discs infiltrated with ACC had transient increase in ethylene production after 4 hours of damage. This response demonstrates that the ACC synthase enzyme is not stimulated by physical damage and ACC oxidase enzyme has its activity increased only for a short period. In contrast, the damaged leaves had a higher accumulation of phenolic compounds and higher respiratory rate than undamaged leaves.
ethylene; respiration; chlorophyll; phenolics compounds; Xanthosoma sagittifolium (L.) Schott
