Influence of UV-B radiation and Cd2+ on chlorophyll fluorescence, growth and nutrient content in Brassica napus

photochemical quenching (q NPQ ) was measured using a pulse amplitude modulated fluorometer. The q NPQ The possible interaction of two stresses, UV-B radiincreased with increasing Cd, while the combination ation and cadmium, applied simultaneously, was of cadmium and UV-B reduced the q NPQ compared to investigated in Brassica napus L. cv. Paroll with that in plants exposed only to cadmium or UV-B radirespect to chlorophyll fluorescence, growth and ation. The chlorophyll a5b ratio showed a reduction uptake of selected elements. Plants were grown in with UV-B at no or low Cd concentrations (0 mM, 0.5 mM nutrient solution containing CdCl 2 , (0, 0.5, 2 or 5 mM) CdCl 2 ), but not at the higher Cd concentrations used and irradiated with photosynthetically active radiation (2 mM, 5 mM CdCl 2 ). Thus in some instances there (PAR, 400–700 nm, 800 mmol m−2 s−1) with or withappeared to be a UV-B and Cd interaction, while in out supplemental ultraviolet-B radiation (UV-B, 280– others plant response could be attributed to either 320 nm, 15 kJ m−2 d−1, weighted irradiance). After treatment alone. 14 d of treatment, the most pronounced effects were found at 2 and 5 mM CdCl 2 with and without supple