SUN, XIAOYONG AND ROGER D. MEICENHEIMER.* Department of Botany, Miami University, Oxford, OH 45056. - Auxin Distribution in Pisum sativum Shoot Apical Meristems.
Pisum sativum cv. Telephone were grown in a 8:16/27:22 L:D
controlled environment to prolong vegetative shoot development.
Shoot apices were sampled at various times during the plastochron
using a stipule length plastochron index. Stems were prefixed with
1-ethyl-3-(dimethyl-aminopropyl)-carbodiimide hydrochloride to
stabilize the location of free endogenous indole-3-acetic acid (IAA)
in the shoot apical meristem and leaf primordia. Serial transverse
sections were immunolabeled with a commercially available primary
monoclonal antibody against IAA. IAA location was visualized using
Western Blue stabilized substrate for alkaline phosphatase secondary
antibody. Quantitative comparisons between the amount of label on the
halves of the shoot apical meristem adjacent to and opposite the
youngest leaf primordium were performed to test the hypothesis that
just prior to leaf primordium initiation a population of shoot apical
meristem cells is transformed from auxin sink cells to auxin source
cells.
Key words: Auxin, Immunolabelling, Leaf Primordia, Pisum sativum, Shoot Apical Meristem