Freezing tolerance in Algerian populations of Atriplex halimus and Atriplex canescens

Abstract

The freezing tolerance of populations of the fodder species Atriplex halimus L. and Atriplex canescens (Pursh.) Nutt (Chenopodiaceae) from different locations in Algeria was investigated, in relation to plant provenance and leaf cation concentrations. For two populations of A. halimus, the effect of increased soil salinity (addition of NaCl) on tolerance was determined. Tolerance was determined in leaf electrolyte leakage assays and by assessment of visual damage, after exposure to temperatures between -5 and -25 C deg. There was significant correlation (P <0.005) between freezing tolerance and the leaf sap concentrations of Na and Na+K, tolerance being improved markedly by soil salinisation, but no relationship between tolerance and the soil salinity or minimum winter temperatures of the original sites of the populations. It is concluded that, for these halophytic species, the soil salinity (supply of ionic osmolytes) at cold-winter sites will be of great importance regarding the likely freezing damage.