Open AccessAbscisic Acid Biosynthesis in Isolated Embryos of Zea mays L.
Author(s) -
Douglas A. Gage,
Franklin Fong,
Jan A. D. Zeevaart
Publication year - 1989
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.89.4.1039
Subject(s) - abscisic acid , zea mays , biosynthesis , xanthophyll , embryo , incubation , carotenoid , biology , biochemistry , chemistry , enzyme , microbiology and biotechnology , gene , agronomy
Previous labeling experiments with (18)O(2) have supported the hypothesis that stress-induced abscisic acid (ABA) is synthesized through an indirect pathway involving an oxygenated carotenoid (xanthophyll) as a precursor. To investigate ABA formation under nonstress conditions, an (18)O(2) labeling experiment was conducted with isolated embryos from in vitro grown maize (Zea mays L.) kernels. Of the ABA produced during the incubation in (18)O(2), three-fourths contained a single (18)O atom located in the carboxyl group. Approximately one-fourth of the ABA synthesized during the experiment contained two (18)O atoms. These results suggest that ABA synthesized in maize embryos under nonstress conditions also proceeds via the indirect pathway, requiring a xanthophyll precursor. It was also found that the newly synthesized ABA was preferentially released into the surrounding medium.