PHLOEM MOBILITY OF FLUORESCENT XENOBIOTICS IN ARABIDOPSIS IN RELATIONTO THEIR PHYSICOCHEMICAL PROPERTIES

The transport of a range of fluorescent probes within the root phloem of Arabidopsis thaliana has been imaged using the confocal laser scann ing microscope. The phloem mobility of these probes and their subseque nt subcellular distribution in the cells of the 'unloading zone', clos e to the root tip, are discussed in relation to a structure-activity r elations (SAR) model. This is a generalized model describing the inter action of low molecular weight xenobiotics with living cells, based on the physicochemical properties of the former. The work demonstrates t hat the model can be used to predict the phloem mobility of xenobiotic s, but only partly predicts the subcellular distribution of phloem-mob ile probes following unloading, The potential use of phloem-mobile flu orescent probes as physiological indicators is discussed.