Effect of increased salinity on CO2assimilation, O2evolution and the δ13C values of leaves ofPlantago maritimaL. developed at low and high NaCl levels

摘要

The effect of increased salinity on photosynthesis was studied in leaves ofPlantago maritimaL. that developed while plants were at low and high NaCl levels. In leaves that developed while plants were grown at 50 mol·m-3, exposure to 200 and 350 mol·m-3NaCl resulted in reductions in net CO2assimilation and stomatal conductance. The decline in CO2assimilation in plants at 200 and 350 mol·m-3NaCl occurred almost exclusively at high intercellular CO2concentrations. The initial slope of the CO2assimilation-intercellular CO2(A-Ci) curve, determined after salinity was increased, was identical or very similar to that measured initially. In contrast to the reductions observed in CO2assimilation, there were no significant differences in O2evolution rates measured at 5 CO2among leaves from plants exposed to higher salinity and plants remaining at low salini