ABSTRACT
Photosynthetic responses to salinity are species specific, and the chief difference between halophytes and glycophytes is that the former can tolerate higher salinity levels than the latter. The photosynthetic capacity of some halophytes has been reported by L. B. Flanagan and R. L. Jefferies to be directly under the control of stomatal conductance, but the relative effects of stomatal vs. nonstomatal control of photosynthesis in halophytes exposed to salinity stress appears to vary between taxa. Halophytes differ among species in their net assimilation rate response to increased salinity, but most species will have a decrease in photosynthetic activity at some salinity level. Carbon isotope ratios became more positive with increased salinity. Luttge et al. determined from an analysis of carbon isotope ratios that two succulent halophytes from the northern coast of Venezuela, Batis maritima and Sesuvium portulacastrum carried out the C3 pathway of photosynthesis.
