Photosynthetic response of cabbage in cadmium-spiked soil

Abstract

Efficiency of a photosynthetic apparatus in plants growing in cadmium-spiked soil as well as plant biomass and cadmium accumulation were assessed in two cabbage cultivars (early and late) in a long-term pot experiment. Cadmium concentrations were 10 and 40 mg(Cd) per kg of dry mass of soil. The early cultivar showed a dose-dependent and stable decrease in SPAD index, while in plants of the late cultivar the response was reversible and less pronounced. A huge drop in the effective quantum yield of PSII photochemistry, photochemical quenching, nonphotochemical quenching, and electron transport rate in the third week of vegetation indicated susceptibility of the early cultivar to cadmium, contrary to the late one. Fresh mass of plants of the early cultivar was diminished by both doses of Cd. For the late cultivar, there was no change in these parameters, indicating its possible usability for phytoremediation, provided the reclaimed area is fenced and protected. Particular attention should also be paid towards late cultivars cabbage farming in areas with a high Cd content. On the other hand, the early cultivar may serve as a bioindicator of Cd-contamination.