Eucalyptus gunnii and Eucalyptus pulverulenta ‘Baby Blue’ Essential Oils as Potential Natural Herbicides |
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Authors: | Cristina Danna Laura Cornara Antonella Smeriglio Domenico Trombetta Giuseppe Amato Pierluca Aicardi Laura De Martino Vincenzo De Feo Lucia Caputo |
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Affiliation: | 1.Department of Earth, Environment and Life Sciences, University of Genova, 16132 Genova, Italy; (C.D.); (L.C.);2.Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;3.Department of Pharmacy, University of Salerno, 84084 Fisciano, Italy; (G.A.); (V.D.F.); (L.C.);4.Pierluca Aicardi, Coldiretti Savona, 17100 Savona, Italy; |
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Abstract: | The phytotoxicity and eco-compatibility of essential oils (EOs) from Eucalyptus gunnii (EG) and E. pulverulenta ‘Baby Blue’ (EP), cultivated in Italy for their cut foliage, were investigated. Leaf micromorphology, EOs phytochemical characterization, and phytotoxicity were analysed. EP revealed a significantly higher oil gland density and a higher EO yield with respect to EG. In both EOs, 1,8-cineole was the major compound (~75%), followed by α-pinene in EG (13.1%) and eugenol in EP (7.5%). EO phytotoxicity was tested on both weeds (Lolium multiflorum, Portulaca oleracea) and crops (Raphanus sativus, Lactuca sativa, Lepidium sativum, Solanum lycopersicum, Pisum sativum, Cucumis sativus). EG EO inhibited germination of P. oleracea, R. sativus, and S. lycopersicum seeds (ranging from 61.5 to 94.6% for the higher dose used), while affecting only radical elongation in S. lycopersicum (ranging from 66.7 to 82.6%). EP EO inhibited germination of P. oleracea and R. sativus (ranging from 41.3 to 74.7%) and affected radical elongation of L. sativum and L. multiflorum (ranging from 57.4 to 76.0%). None of the EOs affected the germination and radical growing of L. sativa, P. sativum, and C. sativus. Moreover, EP EO was more active than EG EO in inhibiting α-amylase, a key enzyme for seed growth regulation. Brine shrimp lethality assay showed that both EOs are safe for aquatic organisms, suggesting their high eco-compatibility. The data collected provide useful information for future applications of these EOs in agriculture as safe and selective bioherbicides. |
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Keywords: | Eucalyptus, oil cavities, micromorphology, essential oils, natural herbicides, phytotoxicity, α -amylase, eco-compatibility |
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