Abstract

D. A., Meloni et al. Glyphosate drift inhibes photosynthesis and produces oxidative stress to Eucalyptus camaldulensis. Quebracho (Santiago del Estero) [online]. 2019, vol.27, n.1, pp.5-5.  Epub Sep 01, 2019. ISSN 0328-0543.

Developing plantations of Eucalyptus camaldulensis has high potential in north-west Argentina since wood of physical and mechanical features appropriated for industrial use can be obtained. Managing forest plantations demands using herbicides, being glyphosate the most frequently employed. This work aimed to test the hypothesis that glyphosate drift inhibes photosynthesis and produces oxidative stress to E. camaldulensis. Tests were carried out in a greenhouse by applying doses of 3 and 6 L ha-1 of glyphosate on one-year old E. camaldulensis seedlings and a control left untreated. Ten days later, the emissions of modulated fluorescence and gas exchange were measured, and the concentration of malondialdehyde (MDA) besides the activities superoxide dismutase (SOD) and peroxidase (POD) were quantified. A 10- replicate completely randomized experimental design was utilized and the results analyzed using ANOVA and the Fisher’s Test. Both doses of glyphosate lowered the number of centers of reaction active and increased energy dissipation as heat; the highest dose brought about photoinhibition. A decrease of the photosynthetic rate occurred due to the inhibition of the photochemical stage and stomate closure. The herbicide caused lipid peroxidation despite the increase of the SOD and POD activities. The hypothesis was confirmed.

Keywords : red eucalyptus; modulated fluorescence; gas exchange; herbicides.

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