Genetic and analitical techniques for auxin studies

New techniques and applications are described for the stdying problems related to the biochemical regulation of auxin levels in higher plants. Use of mass spectrometry with stable isotope labeled internal standards allows rapid and precise analysis of endogenous auxin. A simple purification protocol is described to enhance the power of quantitative gas chromatography-mass spectrometry. Careful applications of hydrolysis tehniques also allow studies of complex conjugated forms of IAA and recent findings on use of such procedures are reported. All of these methods can be applied to a variety of plant materials, however special techniques must be used with woody plants and these are described. Finally, a system using cultures of the aquatic monocot, Lemma gibba, for the selection of hormone metabolism mutants is described. One mutant obtained has an auxin level over 100 times normal and is an excellent model plant for use in modern studies of auxin biosynthesis and its regulation.