Sensitivities of lipoxygenase-lacking soybean seeds to accelerated aging and their chemiluminescence levels

Lipoxygenase (LOX, EC 1.13.11.12)-lacking mutant seeds of soybean (Glycine max), deficient in LOX 1 and 3 (L-1,L-3 less), or LOX 2 and 3 (L-2,L-3 less) activities, were used to study the physiological role of these LOX types in the process of accelerated aging in comparison with normal soybean cv Suzuyutaka. When stored at 40°, 100% relative humidity for 1-10 days, germination data indicated that the absence of LOX land 3 or LOX 2 and 3 did not increase the resistance of seeds to accelerated aging, whereas L-2,L-3 less seeds were more sensitive to the treatment than normal seeds and L-1,L-3 less seeds less sensitive. There were significant differences between normal and L-2,L-3 less seeds, also between L-1,L-3 less and L-2,L-3 less ones, but not between normal and L-1,L-3 less ones. Spontaneous chemiluminescence (CL) of soybean seed homogenates showed that L-2,L-3 less seeds had the lowest CL both at pH 6.6 and pH 9.0. There were no LOX mutation derived differences in phospholipid content and fatty acid composition. Such data suggested that LOX, especially LOX 2, may play some important physiological role in maintaining viability rather than promoting senescence of soybean seeds.