Phloem mobility of fluorescent xenobiotics inArabidopsisin relation to their physicochemical properties

Abstract

The transport of a range of fluorescent probes within the root phloem of Arabidopsis thaliana has been imaged using the confocal laser scanning microscope. The phloem mobility of these probes and their subsequent subcellular distribution in the cells of the ‘unloading zone’, close to the root tip, are discussed in relation to a structure-activity relations (SAR) model. This is a generalized model describing the interaction of low molecular weight xenobiotics with living cells, based on the physicochemical properties of the former. The work demonstrates that the model can be used to predict the phloem mobility of xenobiotics, but only partly predicts the subcellular distribution of phloem-mobile probes following unloading. The potential use of phloem-mobile fluorescent probes as physiological indicators is discussed.