Assessment of photochemical performance of photosystem II in Limbarda crithmoides and Helianthus annuus under Pb stress using chlorophyll a fluorescence kinetics

In the present work, effectiveness of chlorophyll a fluorescence as quick tool to detect effect Pb–stress on Limbarda crithmoides and Helianthus annuus species, when exposed increasing Pb concentrations (0–500 µmol.L–1) for 45 days, was evaluated. The level in plant leaves, well fresh weight content shoots roots both were also determined. L. did not show any significant variation photochemical quenching parameters energy fluxes all despite change OJIP plot 100 µmol.L–1 Pb. addition, increase noted along with an biomass production. However, H. annuus, stress increased absorption, dissipation trapping decreased transport electron rate. curve showed notable modification at 300 500 Pb, without changes contents production under concentrations. Results revealed that accumulated accumulation more notorious treated plants. Lead exhibited different influence photosystem II performance thus, evaluation very efficacious reflect physiological status stress.