To elucidate the physiological and morphological responses generated by vanadium (V) in plants, hydroponic culture experiments were performed with swamp morning glory (Ipomoea aquatica Forsk) exposed to 0 to 2.50 mg L(-1) pentavalent V [V(V)] in Hoagland nutrient solutions. The concentration of chlorophyll a, chlorophyll b, and carotene peaked at a V(V) concentration of 0.05 mg L(-1) and gradually decreased at higher V(V) concentrations. Similarly, the plant biomass was stimulated at low levels of V(V) and was inhibited when V(V) concentrations exceeded 0.1 mg L(-1). V(V) had negative effects on the uptake of phosphorus (P) by roots, shoots, and leaves. The biological absorption coefficients of V of the roots were higher than those of the aerial parts. Under low concentrations of V(V) exposure, the predominant species of V in the aerial parts was tetravalent V [V(IV)], whereas V(V) became more prevalent when concentrations of V(V) in the solution was higher than 0.50 mg L(-1) . However, in the roots the concentrations of V(V) were always higher than those of the V(IV) besides the control group. Organelles in the V(V)-treated leaves were distorted, and the periplasmic space became wider. The authors concluded that these results indicate V(V) has concentration-dependent effects on the physiological properties of swamp morning glory, whereas the plant has the ability to develop self-protective function to adapt to the toxicity of V(V).
Authors: Chen T, Li TQ, Yang JY. ;Full Source: Environmental Toxicology & Chemistry. 2015 Aug 28. doi: 10.1002/etc.3226. [Epub ahead of print] ;