Carbon isotope discrimination in the C4 shrub Atriplex confertifolia along a salinity gradient

Carbon isotope discrimination (∆) was measured for leaves of Atriplex confertifolia along a salinity gradi~ ent in northern Utah. Over this gradient, the variation of ∆ values was high for a C4 species, and the ∆ values were positively correlated with salinity in both years of the study. Of the possible explanations for this pattern, the ∆ results are consistent with the notion that salinity induces an increase in the bundle sheath leakiness of these C4 plants.