Germination ofProsopis argentinaandP. alpatacoseeds under saline conditions

Prosopis argentinaandP. alpatacoare shrubs occupying areas with different soil characteristics within the temperate arid zone of Argentina:P. alpatacooccurs in periodically flooded, clayish and saline areas;P. argentinaoccurs in non-saline sand dunes. The former may have developed adaptive tolerance to salt stress while the latter did not. The objective of this work was to determine the effects of salinity, and its interaction with temperature, on the germination of these species. Increasing concentrations of NaCl solutions (0, 0•2, 0•3, 0•4 and 0•6 mol kg−1NaCl) at 25°C and 35°C were tested. Daily and final germination percentages, as well as germination rate, were recorded under controlled conditions. Results show that increasing salinity caused a decrease in both rate of germination and final percentages for both species,P. alpatacobeing more salt-tolerant thanP. argentina. The greatest differences appeared between 0•3 and 0•4 mol kg−1NaCl. Germination was more affected by salinity at 35°C than at 25°C for both species