The interactive effect of heavy metals and UV-B radiation on two cucumber cultivars

The effects of supplemental UV-B (sUV-B) irradiance, and Cd and Ni treatment alone and in combination were evaluated on heavy metal accumulation, and growth, biomass, and yield responses in 2 cucumber cultivars (Cucumis sativus L. cultivars Local Super Green and Tripti-19). Responses to the combined application of Cd and Ni in both cultivars were antagonistic. Cultivar Tripti-19 showed more sensitivity in terms of yield response towards sUV-B and heavy metals than did Local Super Green. sUV-B exposure increased the concentration of Cd/Ni in the roots, shoots, and fruits of cucumber plants, as compared to the unexposed plants. Bioaccumulation of Cd, vis-a-vis its translocation to different parts of the plants, was higher than that of Ni under sUV-B exposure conditions. The present results clearly suggest that heavy metals and sUV-B in combination had more of a detrimental effect on the test cucumber cultivars than when they were administered separately. As such, cultivation of cucumber cultivars is recommended under greenhouse or other controlled environmental conditions in order to avoid accumulation of heavy metals.