Resumo

OROCIO-CARRILLO, J.A. et al. Response in the antioxidant defense system of Leersia hexandra Sw. to the exposure of petroleum hydrocarbons. Polibotánica [online]. 2023, n.55, pp.245-262.  Epub 26-Maio-2023. ISSN 1405-2768.  https://doi.org/10.18387/polibotanica.55.16.

This study was conducted to assess the impact of petroleum hydrocarbon toxicity on growth, fresh biomass production, photosynthetic pigments and antioxidant response in Leersia hexandra after 180 days. A completely randomized experimental design was performed under semi-controlled conditions in a micro-tunnel, with four treatments and four replicates per treatment. The concentrations were: 0 (control), 30, 60 and 90 g kg-1 of total petroleum hydrocarbons (TPH). The results showed that TPH concentrations in the soil affected growth by reducing height (r= -0.940**), primary root length (r= -0.961**) and aerial fresh matter production (r= - 0.901**), however, they induced an increase in the number of shoots in the tiller (r= 0.970**), number of primary roots (r= 0.995**), production of fresh root matter (r= 0.882**), content of photosynthetic pigments and total proteins (TPr) (r= 0.716**). When L. hexandra is exposed to high doses of HTP (60 and 90 g kg-1) it does not show evidence of oxidative stress because the H2O2 content in these concentrations were statistically equal to the control, this could be related to the relationship positive that it has with total phenols (r = 0.525*) because of soil contamination by oil.

Palavras-chave : petroleum; grass; reactive oxygen species; growth; photo-synthetic pigments.

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