Putrescine treatment reduces yellowing during senescence of broccoli (Brassica oleracea L. var. italica)

Broccoli undergoes yellowing very quickly in storage, which impacts its' quality and economic value. The current study examined the ability of putrescine to inhibit postharvest yellowing of broccoli florets. Broccoli heads were dipped in a 0.25 mmol L-1 solution of putrescine for 10 min, air dried, and then stored at 20 degrees C in the dark. Results indicated that, relative to the untreated control, putrescine treatment effectively suppressed changes in fruit color from green to yellow, reduced the degradation of chlorophyll, decreased electrolyte leakage, inhibited the accumulation of malondialdehyde, and maintained the enzyme activity and gene expression of peroxidase, catalase, and ascorbate peroxidase. The relative expression of chlorophyllase. (BoCLH1) and chlorophyllase. (BoCLH3) was enhanced while the relative expression of chlorophyllase. (BoCLH2), pheophorbide a oxygenase (BoPAO), and pheophytinase (BoPPH) was reduced by putrescine. The data clearly indicate that putrescine reduces the yellowing of broccoli florets and may represent an effective approach for reducing postharvest losses in broccoli.