THE GERMINATION OF FOUR ANNUAL STRAND-LINE SPECIES

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Summary

The germination of four strand-line annuals, Atriplex glabriuscula, Atriplex lacimata, Cakile maritima and Salsola kali, was studied in the field and laboratory. Germination in the field began approximately 1 month after the spring equinox. Thus, seedling establishment was not directly affected by high spring tides. The relative importance of the various biological and environmental factors influencing the timing of germination of these species is discussed.

The effects on germination of salinity and temperature and various interactions between these two factors were characterized. From experiments designed to determine the nature of the inhibition of germination by saline solutions, it was concluded that, in the Atriplex spp., the inhibition was purely osmotic but, in C. maritima and S. kali, ionic toxicity is important. The potential for dispersal of strand-line species by sea-currents depends upon the buoyancy of the fruit and the ability of the seed to survive prolonged immersion in seawater. Laboratory experiments showed that the four species differed considerably in these characteristics.

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