Endogenous IAA and 4-chloroindole-3-acetic acid (4-CI-IAA) were analysed in vegetative and reproductive tissues of the garden pea (Pisum sativum) using GC-MS selected ion monitoring in the presence of stable-isotope labelled internal standards. In fruit collected 3-8 days after anthesis (DAA) conjugates of both auxins were more abundant than the free hormones. Auxin levels (ng g-1 fr. wt) in the seeds were higher by 1-2 orders of magnitude than in the pericarps. However, as seeds are small at this stage, the pericarp nevertheless contains a substantial fraction of the overall quantity of IAA and 4-CI-IAA. While, in young fruit tissues, IAA was more abundant than 4-CI-IAA, the opposite was true for seeds at the 'table-ready' stage and for roots of nine-day-old seedlings. Our data suggest that both IAA and 4- CI-IAA are required to coordinate the vegetative and reproductive growth of pea plants.
Bibliographical noteFunding Information:
Acknowledgements-Supported in part by the Min-nesotaA gricultural ExperimentS tation, Publication Number 961210001A.d ditional funding by grantsn o. IBN-9106039-02 (NSF), OGP0138166 (NSERC), DE-AI02-94ER20153 (DOE), and JF202 (U.S.-Croatian ResearchA greement)t o Mark L. Brermer, Jocelyn A. Ozga,J erry D. Cohen,a nd Volker Magnus is gratefully acknowledgedW. e thank Thomas P. Krick (Departmento f Biochemistry,U niversity of Minnesota) for help and advice with the GC-MS work.
- 4-chloroindole-3-acetic acid
- Free and conjugated auxin
- Garden pea
- Hormone analysis
- Pisum sativum