Determinations of indole-3-acetic acid in xylem sap of Ricinus communis L. using mass fragmentography.

Mass fragmentography employing a deuterated internal standard was used to make quantitative analyses of indole-3-acetic acid in xylem sap collected from Ricinus communis L. When contamination of the sap by microorganisms was reduced by frequent collection, levels of IAA were found to be less than 0.5 ng ml(-1). It is therefore proposed that the transpiration stream does not play a significant role in the transport of IAA within the plant.