, BORIE BORIE, FERNANDO RICARDO, Medina, Jorge, Monreal, Carlos M., Orellana, Luis, Calabi-Floody, Marcela, González, María Eugenia, Meier, Sebastián, Borie, Fernando R., Cornejo, Pablo E.

Cellulose and lignin as main components of crop residues have a significant influence on composting operations and composition of the final products. Both are strongly associated, and lignin can be considered an important barrier during the biodegradation process of lignocellulosic materials. Saprophytic fungi are efficient lignin degraders due to their complex enzymatic system. Therefore, the influence of the inoculation of saprophytic fungi (Coriolopsis rigida, Pleurotus ostreatus, Trichoderma harzianum and Trametes versicolor) and the supply of inorganic additives (Al2O3, Fe2O3 and allophanic soil) that promote the stabilization of carbon (C), were analyzed in the biodegradation of wheat straw (WS). The activity of Laccase (LAC), manganese peroxidase (MnP) and ?-glucosidase and changes in temperature, pH and E4/E6 ratio were analyzed in a biodegradation process of 126 days. The activity of LAC, MnP and the E4/E6 ratio were significantly influenced and increased (enzymes) by fungi species, inorganic additives, and time of inorganic material addition, as well as their interactions (p < 0.05). The WS inoculated with T. versicolor showed the highest average activities for LAC, MnP and ?-glucosidase (2000, 220 UL?1 and 400 ?mol pNP g?1 h?1 respectively). Furthermore, the addition of Al2O3 and Fe2O3 increased all the activities regarded to the decomposition of WS and influenced the changes associated with the stabilization of OM in composted WS. In conclusion, the inoculation of WS with T. versicolor in combination with metal oxides improved the enzyme related to the biodegradation process of WS favorizing its stabilization in the medium time, which is of importance in the composting of residues with high C/N ratio. © 2023 Elsevier B.V., All rights reserved.

, BORIE BORIE, FERNANDO RICARDO, Santander, Christian, Sanhueza, Mario Aguirre, Olave, Jorge, Borie, Fernando R., Valentine, Alex J., Cornejo, Pablo E.

Soil salinity is the biggest problem which hinders the productivity of agricultural crops, causing adverse effects on plant growth and development. In this regard, it has been shown that the arbuscular mycorrhizal fungi (AMF) can establish a symbiosis with most agricultural plants improving water and nutrient absorption under salinity stress conditions. The functional contribution of AMF strains (Claroideoglomus claroideum (Cc) and a native consortium of AMF (HM) isolated from saline soils) on the growth and nutrition of lettuce plants (Lactuca sativa var. longifolia) was evaluated under increasing salt stress conditions (0, 40, and 80 mM NaCl). At 60 days of growth, biomass production, nutrient content (N, P), ions (Ca2+, Mg2+, Na+, K+), chlorophyll, proline content, and AMF propagules were evaluated. The highest growth was observed in plants inoculated with Cc, which produced a higher percentage of root colonization and hyphal length at all levels of salinity, compared to plants inoculated with HM or non-inoculated plants. These results were directly related to higher biomass production, increased synthesis of proline, increased N uptake, and noticeable changes in ionic relations, based in a diminishing Na+, compared to non-mycorrhizal plants. Our results suggest that this improved ionic balance is due to a filtering effect of AMF structures both in the soil and in the root that prevents the entry of toxic Na+ ions, which is important due to the level of lettuce production on saline soils improving the crop by means of directed inoculation with efficient AMF strains. © 2019 Elsevier B.V., All rights reserved.