Changes in Abscisic Acid Levels During Imbibition and Germination of Non-Dormant and Thermodormant Lettuce Seeds

Abstract

Non-dormant lettuce seeds (Lactuca sativa L. cv. Great Lakes) have an optimum temperature for germination of about 25°C. When the seeds were imbibed for 20 h at this temperature their content of abscisic acid fell from 98.0 ng per g fresh weight to less than 6 ng per g original fresh weight. When seeds were imbibed at 10 and 32°C, they exhibited dormancy. An inverse relationship was found between the abscisic acid content of the seeds and their percentage germination.