Dados do Trabalho

Título

PHYSIOLOGY AND UPTAKE OF SILICON AND METALS IN MAIZE GROWN IN A POLLUTED SOIL AMENDED WITH BIOCHAR

Resumo

Biochars in soils polluted by heavy metals can improve plant nutrition by Si and photosynthetic capacity of energy crops and alleviate toxicity, promoting greater tolerance to stress. In this sense, the objective of this work was to evaluate the accumulation of Si and heavy metals (Cd, Pb and Zn) in maize plants, as well as to investigate the mitigation of the stress caused by metals through the functioning of the photosynthetic apparatus of maize leaves, grown in soil polluted by metallurgical slag and treated with rice straw biochar (RSB). Maize plants were cultivated in a greenhouse for 45 days using soil polluted by metals and treated with doses of RSB (0.0, 5.0, 10.0, 20.0 and 30.0 t ha−1). The physiological indicators investigated were chlorophyll fluorescence, levels of photosynthetic pigments and gas exchange parameters. Accumulations of Si, Cd, Pb and Zn were investigated in the aerial part of the plant. Doses of RSB significantly increased Si absorption, while reducing Cd, Pb and Zn accumulation in maize shoots. The addition of 30.0 t ha−1 RSB promoted reductions of 18, 34 and 37% for Zn, Cd and Pb in maize leaves, respectively, in relation to the control. Gas exchange parameters increased by 63%; similarly, chlorophyll a/b and carotenoid contents increased by 77, 57 and 42%, respectively. Chlorophyll fluorescence results indicated a linear and positive relationship between photosystem II energy consumption efficiency (Fv/Fm) and RSB doses. The application of RSB in soil polluted by Cd, Pb and Zn was efficient in reducing the stress of metals caused to maize plants and is a promising phytotechnology to phytoattenuate polluted sites, through the generation of energy via plant biomass and income gain with land use.

Palavras-chave

phytoattenuation, immobilization, soil remediation, photosynthesis.

Instituição financiadora

CAPES, CNPq e FACEPE