Membrane effects in postharvest physiology

Plant tissue deterioration is of prime importance to food and horticultural scientists. Experimental evidence continues to be gathered supporting membrane damage as the key event leading tn a cascade nf biochemical reactions culminating in tissue deterioration and economic loss. In this paper, the sequence of occurrences in plant membranes during natural senescence and resulting from postharvest stresses are reviewed and compared. The picture emerging from numerous studies devoted to this topic is of membrane lipids undergoing extensive chemical degradation. Biophysical changes in membrane lipids and enzymatic and non-enzymatic lipid peroxidation leads to altered membrane properties and result in defects such as ion leakage and cellular decompartmentation. Postharvest stresses including chilling injury and freezing injury often lead to similar patterns of deterioration. However, it is too early to conclude positively that a truly universal mechanism for both senescence and postharvest stress-induced membrane damage exists.