Abstract: The objective of this study was to relate membrane lipid peroxidation and browning in lily bulbs (Lilium lancifolium Thunb.) grown in Yixing, Jiangsu during postharvest cold storage. It was demonstrated that browning degree, cell membrane permeability, superoxide anion radicals production rate, hydrogen peroxide (H2O2) and malondialdehyde contents increased in all bulb parts with storage time. The rate of increase in these parameters was always higher in the middle layer than in the outer and inner layers of bulbs. The activities of exogenous peroxidase (POD), superoxide dismutase (SOD), catalase (CAT) and lipoxygenase (LOX) increased initially and decreased thereafter. The middle layer of bulbs showed higher SOD and CAT activities but lower POD and LOX activity than that of the two other layers. Cell viability in lily bulbs gradually decreased with storage time, and it was higher in the middle layer than in the two others. Browning was closely related to membrane lipid peroxidation in lily bulbs. The rate of browning was different among different bulb parts, in the decreasing order of inner > outer > middle layers. The results from this study can provide an experimental basis for understanding the mechanism of lily browning.

Key words: lily bulbs, browning, membrane lipid peroxide