Santana K.B.,University Estadual Of Santa Cruz |
de Almeida A.A.F.,University Estadual Of Santa Cruz |
Souza V.L.,University Estadual Of Santa Cruz |
Mangabeira P.A.O.,University Estadual Of Santa Cruz |
And 4 more authors.
Environmental and Experimental Botany | Year: 2012
Genipa americana L. is a tree that tolerates soil flooding and high levels of Cr 3+, therefore it can be used in recomposition of ciliary forests at chromium-polluted watersheds. In this study, the ability of G. americana to phytoremediate the two major ionic Cr forms was assessed through Cr 3+ and Cr 6+ speciation, leaf gas exchange, growth and chemical composition of seedlings under Cr 3+ and Cr 6+ treatments. In greenhouse experiment, 4-month old seedlings were transferred to nutrient solution and, after three months, were submitted to 15 and 30mgL -1 of each ionic Cr form. After 15-days, leaf gas exchanges were measured and seedlings were sampled for evaluation of growth and chemical composition. Results showed that Cr 6+ is fully converted into Cr 3+ inside the plant; the absorption of Cr 3+ and Cr 6+ interfered with the absorption kinetics of Zn, Cu, Fe, K, Mg, Ca and P; increments in nutrient solution of Cr 6+ decreased root biomass and of both forms decreased shoot biomass; both Cr ions increased leaf area; mainly the exposure to Cr 6+ form decreased net photosynthesis per unit leaf area, stomatal conductance to water vapor and leaf transpiration; and Cr highly accumulated in roots only as Cr 3+, independently from the ionic form applied to seedlings. Hence, although exposure to Cr 3+ and Cr 6+ affected growth and development of G. americana seedlings, this woody species demonstrated a relevant capacity for phytoremediation of chromium, by phytostabilizing Cr 6+ and rhizofiltering Cr 3+. © 2012 Elsevier B.V.