Arsenic and vanadium in soils: effects on photosynthetic chain dynamics in Ocimum basilicum L.

The effects on the growth of basil (Ocimum basilicum L.) due to the presence of arsenic and vanadium, recently incorporated on the soil, were studied. Besides biomass and morphology, particular emphasis was placed in studying the effect on photosynthetic systems by spectroscopical methods, including reflectance and fluorescence (both stationary and variable) measurements. Assays were conducted in quadruplicate in the presence of arsenic, vanadium and both together, as well as control assays. Arsenic showed stronger effect on growth compared with vanadium, whereas both combined almost stopped growth. The presence of arsenic disrupted the photosynthetic machinery in basil, significantly impairing electron transfer processes within the chloroplasts. Notably, the negative effects on plants were most severe under both contaminants jointly, followed by arsenic alone, whereas vanadium alone showed the lesser effect.