Study on individual and interactive effects of supplemental UV-B radiation and heavy metals on Spinacea oleracea

The effects of supplemental ultraviolet-B (sUV-B) irradiation and heavy metals (Cd and Ni) treatment alone and in combination were evaluated on the growth, biomass and yield of spinach plants. All the stresses caused reduction in biomass yield vis-a-vis alteration in its distribution pattern with more retention in below ground parts leading to higher root shoot ratio. Absolute growth rate (AGR) decreased in all treated plants due to reduction in their height at successive growth stages. Decrease in leaf area and number of leaves due to various stresses was responsible for decline in net assimilation rate (NAR), an index of photosynthetic assimilatory capacity of the plant. Supplemental UV-B increased the bioaccumulation of Cd and Ni in the root and shoot of exposed plants as compared to the control ones. The present study suggested that soil contaminated with Cd or Ni had a more negative impact on yield with higher retention of heavy metals in spinach growing under natural field conditions and exposed with elevated UV-B.