Variation in germination response to temperature and salinity in shrubby Atriplex species

Abstract

Germination response to temperature and salinity was measured for 13 seed accessions of shrubby Atriplex belonging to five species. Optimum germination temperature varied both among and within species, as did maximum germination expressed as percentage of filled seed. All accessions showed depressed germination with increasing salinity at high temperature, while germination percentages at low salt levels frequently exceeded the water control values at intermediate or low temperatures. Within-species variation was not clearly correlated with any habitat attribute. The high degree of variation emphasises that between-species comparisons can only be meaningful if an adequate evaluation of within-species variation is available.