Significant variation in tolerance was found in natural populations of Diplachne fusca (L.) Beauv, grown under a range of NaCl concentrations, with greatest variation in accessions from different sites and a narrower range of tolerance from those within sites. Significant differences were found between accessions for Na, Cl and K uptake. Ma and Cl concentrations were found to be higher in sheaths than in leaf blades, indicating that D. fusca has the capacity to sequester high levels of Na and Cl in the sheath away from the leaf blade as well as maintaining a high selectivity for K. over Na. The salinity level of the site from which an accession was collected did not show any correlation with the salt-tolerance of that accession. While D. fusca was found generally to be highly tolerant of NaCl (with plants surviving at 400 mol m-3 NaCl) there was variation in tolerance in its natural populations, indicating the potential for selecting to increase tolerance further.
Keywords: Diplachne fusca; salinity; sodium; tolerance; variation.