Dry matter and root colonization of plants by indigenous arbuscular mycorrhizal fungi with physical fractions of dry olive mill residue inoculated with saprophytic fungi

Abstract

We studied the influence of indigenous arbuscular mycorrhizal (AM) and saprobe fungi on the phytotoxicity of the physical fractions of dry olive mill residue (DOR). The physical extractions of DOR gave an aqueous (ADOR) and an exhausted (SDOR) fraction with less phytotoxicity for tomato than the original samples. The indigenous AM were able to decrease the phytotoxicity of SDOR inoculated with Trametes versicolor and Pycnoporus cinnabarinus on tomato. However, incubation of ADOR with both saprophytic fungi did not decrease its phytotoxicity in presence of the indigenous AM fungi. The percentage of root length colonized by indigenous AM strongly decreased in presence of DOR, around 80% of decrease at dose of 25 g kg -1 of DOR, but the level of mycorrhization was higher in presence of ADOR or SDOR (38% and 44% of decrease respectively at the same dose). There were no relationships between the effects of the physical fractions of DOR incubated with the saprobe fungi on AM colonization and on plant dry weight of tomato. Our results suggest that the phytotoxicity of the olive residues can be eliminated by the combination of physical extraction and by saprobe fungal inoculation and the use of this agrowaste as organic amendment in agricultural soil may be possible.Additional key words: biofertilizer, bioremediation, olive waste, phytotoxicity, saprobe fungi, Solanum lycopersicum L. ResumenMateria seca y colonización de raíces de plantas por hongos micorrícico arbusculares autóctonos en presencia de fracciones físicas de alpeorujo seco y extractado inoculado con hongos saprobios En este trabajo se ha estudiado la influencia de los hongos micorrízicos arbusculares autóctonos y hongos saprobios en la fitotoxicidad de las fracciones físicas del alpeorujo. La extracción física del alpeorujo con agua produjo un extracto acuoso (ADOR) y un sólido extractado (SDOR) con menor fitotoxicidad para las plantas de tomate que los controles con alpeorujo. Los hongos arbusculares autóctonos son capaces de disminuir la fitotoxicidad de SDOR inoculado con Trametes versicolor y Pycnoporus cinnabarinus en plantas de tomate. Sin embargo, la incubación del ADOR con dichos hongos no modificó la fitotoxicidad del residuo en plantas de tomate cultivadas en suelo no estéril. El porcentaje de longitud de raíz colonizada por los endófitos arbusculares autóctonos disminuyó drásticamente en presencia de alpeorujo (alrededor de un 80% de disminución a la dosis de 25 g kg -1 de DOR) aunque el nivel de micorrización fue superior en presencia de ADOR o SDOR (38 y 44% de disminución a la misma dosis). No se ha encontrado relación entre los efectos de las fracciones físicas del alpeorujo incubado con hongos saprobios en la colonización arbuscular y el peso seco de las plantas de tomate. Nuestros resultados indican que la fitotoxicidad de los residuos del olivar puede ser eliminada por el uso combinado de una extracción física y una incubación biológica con hongos saprobios; por tanto podemos considerar el uso de estos residuos como enmendantes or...

Effect of a New Thermal Treatment in Combination with Saprobic Fungal Incubation on the Phytotoxicity Level of Alperujo

“…8 However, with a combination of physical and biological treatments, the use of this agrowaste as an organic amendment in agricultural soil may be possible. 9 The possibility of enhancing the removal of biorecalcitrant phenols from olive mill wastewaters by pretreatment has been described. 10,11 No studies to diminish the phenol content to enhance further biological treatments have been performed.…”

“…Considerable efforts to decrease the phytotoxicity of dry olive mill residue by different biological, chemical, physical, and physicochemical treatment methods have been made. − Nevertheless, none of these individual approaches appears to be a general solution for reducing these contaminants . However, with a combination of physical and biological treatments, the use of this agrowaste as an organic amendment in agricultural soil may be possible . The possibility of enhancing the removal of biorecalcitrant phenols from olive mill wastewaters by pretreatment has been described. , No studies to diminish the phenol content to enhance further biological treatments have been performed.…”