Peroxidative changes associated with chilling injury in soybean seeds during imbibition

The relationship between lipid peroxidation and fatty acid unsaturation was investigated during imbibitional chilling injury in soybean seeds. Transient changes in lipid hydroperoxide levels were observed in both chilled and non-chilled seeds and axes. However in axes the increase in lipid hg hydroperoxides after 12 hours of imbibition at chilling temperatures was associated with small bur non-significant declines in the levels of linoleic acid, and linolenic acids (9% and 8% respectively) of the total lipid fraction. Increases in lipid hydroperoxides during the chilling of whole seeds and embryonic axes preceded ion leakage by some 40 hours. In an attempt to separate temperature effects from the imbibition process, seeds and axes were imbibed for 12 hours at 5 degrees C or 25 degrees C before transfer to 25 degrees C or 5 degrees C, respectively. Seeds showed no significant changes in fatty acid levels, although axes showed marked changes in the levels of linoleic acid. The capacity of soybean seeds to control lipid peroxidation may be an important component in chilling injury and lead to a loss of unsaturated fatty acids.