Details

Autor(en) / Beteiligte

• SARWAR, MUHAMMAD
• ARSHAD, MUHAMMAD
• MARTENS, DEAN A.
• FRANKENBERGER, W.T.

Titel

Tryptophan-dependent biosynthesis of auxins in soil

Ist Teil von

• Plant and soil, 1992-12, Vol.147 (2), p.207-215

Ort / Verlag

Kluwer Academic Publishers

Erscheinungsjahr

1992

Quelle

SpringerLINK Contemporary (Konsortium Baden-Württemberg)

Beschreibungen/Notizen

• The presence of auxins in soil may have an ecological impact affecting plant growth and development. A rapid and simple colorimetrie method was used to assess California soils for their potential to produce auxins upon the addition of L-tryptophan (L-TRP). The auxin content measured by colorimetry was expressed as indole-3-acetic acid (IAA)-equivalents. A substrate (L-TRP) concentration of 5.3 g kg⁻¹, glucose concentration of 6.7 g kg⁻¹, no nitrogen, pH 7.0, 40°C, shaking (aeration) and 48 h incubation time were selected as standardized conditions to assay for auxin biosynthesis in soil. IAA was confirmed as a major microbial metabolite derived from L-TRP in soil by use of high performance liquid chromatography (HPLC). Under standardized conditions, L-TRP-derived auxins in 19 soils varied greatly ranging from 18.2 to 303.2 mg IAA equivalents (auxins) kg⁻¹ soil. This study suggests that the phenotypic character of the soil microbiota has more of an influence on auxin production than the soil physicochemical properties (e.g., pH, organic C content, CEC, etc.).