ABSTRACT
Last to be added to the list of micronutrients (Broyer et al. 1954), chlorine is group VII halogen element. It has only one stable oxidation valency state (Cl“) and exists in plants as free anion (Cl ), bound to exchange sites or as organic molecules. More than 130 chlorine-containing organic compounds have been reported from plants (Engvild, 1986). Their significance is currently not known, but at least one of these-4-chloroindole acetic acidshows high auxin activity (Flowers, 1988). Chlorine is a structural component of the manganese cluster of photosystem II that catalyzes the oxidation of water. Large accumulation of chloride in the vacuoles suggests its involvement in maintenance of turgor and osmoregulation. Chlorine has also been shown to be involved in regulation of enzyme activities and stomatal functioning (Xu et al. 2000).
