Effect of heavy metals (Hg, As and La) on biochemical constituents of Spinacia oleracea

Toxic heavy metals contamination of soil, water and air by various human activities is a critical environmental problem. Due to increase in geological and anthropogenic activities soil polluted with heavy metals have become common throughout the world. Reduction in growth, performance, and yield is seen in plants growing in these soils. Growing medicinal plants in heavy metal polluted soils affects the biosynthesis of secondary metabolites, causing considerable changes in the quality and quantity of these compounds. The aim of this study was to investigate the effects of Mercury (Hg), Lanthanum (La), and Arsenic (As) on the biochemical constituents (Chlorophyll A and B, protein, phenols, flavonoids, metal chelators and radical scavengers respectively) of Spinacia oleracea. The experimental set-ups were prepared as per standard protocol for plant toxicity testing. Four concentrations of heavy metal salts viz., HgCl2, LaCl3 and As2O3 (25mM, 50mM, 75mM and 100mM) were tested for plant toxicity assessment. A set-up without metal was used as the experimental control. The set-up with Hg showed drastic decrease in vital biochemical constituents that contribute to the growth of the plant; La and as did not seem to have a considerable impact except for slight variations. The apparent ineffectiveness of as and La remains yet to be explored.