Root primordia and endogenous auxin in maize roots cultured in vitro

Quantitative analyses of indol-3yl-acetic acid (I aa ) in Zea mays L. (cv. LG 11) root segments cultured in vitro were performed by gas chromatography-mass spectrometry with selected ion monitoring. The root extracts were first purified by highperformance liquid chromatography. Root primordia initiation in intact and decapitated roots showed different patterns: decapitation strongly enhanced primordia initiation in their first 10 mm. During the culture (5 days), I aa content decreased in both intact and decapitated roots. No correlation was found between the level of endogenous auxin and the numher of root primordia initiated from either intact or decapitated maize root segments.