Occurrence and in Vivo Biosynthesis of Indole-3-Butyric Acid in Corn (Zea mays L.)

Abstract

Indole-3-butyric acid (IBA) was identified as an endogenous compound in leaves and roots of maize (Zea mays L.) var Inrakom by thin layer chromatography, high-performance liquid chromatography, and gas chromatography-mass spectrometry. Its presence was also confirmed in the variety Hazera 224. lndole-3-acetic acid (IAA) was metabolized to IBA in vivo by seedlings of the two maize varieties. The reaction product was identified by thin layer chromatography, high performance liquid chromatography, and gas chromatography-mass spectrometry after incu- showed that maximum activity was reached in inrakom after 1 hour and in Hazera after 2 hours. The pH optimum for the uptake of IAA was 6.0, and that for IBA formation was 7.0. The Km value for IBA formation was 17 micromolar for Inrakom and 25 micromolar for Hazera 224. The results are discussed with respect to the possible functions of IBA in the plant.

Auxin stability and accumulation during in vitro shoot morphogenesis influences subsequent root induction and development in Eucalyptus grandis

“…This could be attributed to the fact that TIBA treatment may actually have led to the cellular accumulation of IAA through the inhibition of IAA efflux, resulting in root induction, or the in vitro conversion of IAA to IBA for root induction. Such a conversion has been previously reported in roots, coleoptiles and leaves of maize (Ludwig-Müller and Epstein 1991). Although the conversion of NAA to IBA has not been reported, it would explain the lowest percentage rooting by NAA-treated shoots (not discounting the influence of endogenous auxins), compared with those supplied with IBA and IAA, all in the presence of TIBA.…”

Auxins in the development of an arbuscular mycorrhizal symbiosis in maize

“…Alize) were cultivated under sterile conditions in the light (28 mmol m À2 s À1 ; Philips fluorescent tubes TL55 and TL32) at 23 1C as previously described (Ludwig-Müller and Epstein, 1991;Ludwig-Müller et al, 1997). Seedlings were harvested after 6 days of culture.…”

Indole-3-butyric acid synthesis in ecotypes and mutants of Arabidopsis thaliana under different growth conditions

“…Zea mays seedlings were found to convert IAA to IBA in vivo (Ludwig-Müller and Epstein, 1991). The in vitro conversion of IAA to IBA in maize seedlings is dependent on a microsomal membrane preparation which forms IBA in the presence of acetyl-CoA and ATP (Ludwig-Müller et al, 1995a).…”