Tobias Ntuli

Effects of the Rate of Drying on the Physiology and Biochemistry: of Excised Embryonic Axes from Desiccation-sensitive Seeds Tobias Ntuli

The results presented here are consistent with the observation that drying and wet storage adversely affected the respiratory enzymes, PFK, MDH and NADH dehydrogenase. It is suggested that the resultant metabolic imbalance led to more leakage of electrons from the mitochondrial electron transport chain than normal, and through lipid peroxidation increased levels of hydroperoxides. In addition, dehydration and hydrated storage may depress the activities of free radical processing enzymes, SOD, CAT and GR and levels of antioxidant, AsA. This phenomenon was less pronounced during rapid, in comparison to slow, desiccation and moist storage. However, it appears that the above biochemical events are overtaken by physical damage at higher water contents in the highly recalcitrant seeds. It was concluded that the differential effects of the drying rate and wet storage on responses of desiccation-sensitive seeds varies with tissue, harvest, species and the degree of desiccation sensitivity.