Salt Tolerance in the Triticeae: Growth and Solute Accumulation in Leaves ofThinopyrum bessarabicum

Abstract

Gorham, J., McDonnell, E., Budrewicz, E. and Wyn Jones, R. G. 1985. Salt tolerance in the Triticeae: growth and solute accumulation in leaves of Thinopyrum bessarabicum.—J. exp. Bot. 36: 1021–1031. The diploid wheatgrass Thinopyrum bessarabicum was found to withstand prolonged exposure to 350 mol m⁻³ NaCl in hydroponic culture. During the gradual addition of salt to the external medium, osmotic adjustment was rapidly achieved by the accumulation of Na and Cl. Following osmotic adjustment constant leaf Na and Cl concentrations were maintained, and K was retained at a high level. Thinopyrum bessarabicum may be described as an osmoconformer, adjusting its internal osmotic pressure to 400–500 mOsmol kg⁻¹ above that of the external medium in hydroponic culture. Both slower shoot initiation and reduced leaf length contributed to the reduced growth rates at higher salinities. Leaf width was not affected. Increasing salinity resulted in increases in leaf concentrations of phosphate, glycinebetaine, sucrose and proline, and in decreases in the concentrations of nitrate, sulphate, magnesium, calcium, total amino acids and organic acids. Thinopyrum bessarabicum exhibits salt tolerance characters which may be useful in wheat breeding.