Factors affecting13C/12C ratios of inland halophytes. II. Ecophysiological interpretations of patterns in the field

摘要

By measuring delta;13C values, 9 of 42 species inhabiting saline sites in Alberta were found to be C4plants. None of these, however, are dominant species in wet saline situations. A salinity gradient was studied along a transect to provide improved field data on delta;13C variations among C3halophytes. Soils were dominated by sulphates of sodium and, less so, magnesium. Soil water potentialwas highest at a depth of about 10ensp;cm and, on a daily basis, changed little. The delta;13C values ofPuccinellia nuttalliana(Schultes) Hitch, were well correlated with. The same appeared true forSalicornia europaeaL. ssp.rubra(Nels.) Brietung. In a scattergram representing five major species, a close correlation was also evident forHordeum jubatumL. The relationship could not be extended toTriglochin maritimaL. andSonchus arvensisL., but values for these two species were not separable from those ofP.nuttallianaandH.jubatum.Salicornia europaeassp.rubra, however, differed by having delta;13C values that were markedly more negative. Although partly associated with cover by other species, this tendency may reflect a lower water-use efficiency as afforded by a greater reliance on the uptake of readily available salt for osmotic adjustment.