DISTRIBUTION OF GIBBERELLINS IN THE SEEDS OF 2 APPLE CULTIVARS
Abstract
Inclusion of 4-hydroxy-5-isopropyl-2-methyl trimethylammonium chloride piperidine carboxylate (AMO-1618) in the stratification medium reduced germination in both ''McIntosh'' and ''Jonathan'' apple seeds from 94% to 17 and 30%, respectively, showing no effect on ''Golden Delicious''. Free and bound levels of gibberellins were also reduced in ''Jonathan'' after 30 days of chilling; this decrease suggests no interconversion of the free form into the bound form. In ''McIntosh'' after 30 days at 5.degree. C the seed coat accumulated the highest level of gibberellins (GAs) (5353 ng/g fresh weight) followed by embryonic axes (14.1 ng/g) and cotyledons (0.33 ng/g) but in ''Jonathan'' embryonic axes contained most of the gibberellins (130 ng/g).