Studies on abscisic acid in apple seeds.

Abscisic acid (AbA) was found to be present in non-stratified apple seeds. The evidence is based on chromatographic behaviour, fluorescence, UV-spectrum and growth inhibition in a wheat-coleoptile straight-growth test.The AbA level, as measured by this bioassay, falls considerably with progressing stratification; after 3 weeks of after-ripening no AbA could be detected in the seeds.The longer the period of stratification, the higher was the concentration of synthetic AbA necessary to inhibit germination.