Endogenous abscisic Acid levels in germinating and nongerminating lettuce seed.

The concentrations of abscisic acid in Grand Rapids lettuce (Lactuca sativa L.) seeds imbibed under conditions which promote or inhibit germination were determined by electron capture-gas chromatography. The concentration of abscisic acid in dry seeds was 12 to 14 nanograms per 100 milligrams. During 24-hour imbibition, the abscisic acid content diminished more rapidly during conditions which allow germination (25 C in light) than in conditions which inhibited germination (35 C in light or darkness at 25 C). A decrease in endogenous levels of abscisic acid was not always correlated with germination.