Summary The fern Pteridium aquilinum is one of the most important invasive species in the world. In Mexico, in the influence area of the Calakmul Biosphere Reserve (REBICA) this species invades and dominates agricultural and livestock land, which leads the peasants to look for new sites for their cultivation, to the detriment of the conserved areas. In this research, chemical and biological properties of soil were evaluated in areas invaded with bracken fern forests and in mature vegetation. Thus, 12 plots with three contrasting conditions, with four repetitions per condition were established: young helechal (HJ; 5-10 years old) and old helechal (HV, more than 25 years old) and mature vegetation (VM). Chemical components were evaluated in the soil: pH, organic matter (MO), organic carbon (CO), total nitrogen and available phosphorus Olsen (P), and biological component like: litter accumulation, rhizoms and macrofauna. In chemical components of the soil, significant differences were found in pH (F = 10.719, P ≤ 0.05) and P (F = 14.377, P ≤ 0.05) of HJ and HV in regard to VM. In biological attributes, it was encountered that the dry matter of litter and the dead rhizomes and its depth varied significantly (F = 5.53, P < 0.05; T = 3.04, P < 0.05; T = 2.57, P < 0.05) between HJ and HV, respectively. Nevertheless, abundance of macrofauna was similar to the three conditions (HV, HJ y VM). In accordance with the edaphic variables studied, it was found that the condition HV is not degraded and even presents favorable conditions to carry out restoration/rehabilitation actions.

Resumen El helecho Pteridium aquilinum es una de las especies invasoras más importantes del mundo. En México, en el área de influencia de la reserva de la Biosfera de Calakmul (REBICA), P. aquilinum invade y domina amplias extensiones de terrenos agrícolas y ganaderos, lo cual lleva a los campesinos a buscar nuevos sitios para cultivar, en detrimento de las áreas con selvas conservadas y protegidas. En esta investigación se evaluaron las propiedades químicas y biológicas del suelo en áreas invadidas por helechales y en vegetación madura. Para ello, se establecieron 12 parcelas con tres condiciones contrastantes, con cuatro repeticiones por condición: helechales jóvenes (HJ; 5-10 años) y viejos (HV; más de 25 años) y vegetación madura (VM). En el suelo se evaluaron los componentes químicos: pH, materia orgánica (MO), carbono orgánico (CO), nitrógeno total (NT) y fósforo disponible Olsen (P) y biológicos (acumulación de mantillo, rizomas y macrofauna). En los componentes químicos del suelo, se encontraron diferencias significativas en el pH (F = 1 0.719; P < 0.05) y P (F = 14.377; P < 0.05) de HJ y HV con respecto a la VM. En los atributos biológicos se encontró que la materia seca del mantillo y de los rizomas muertos del helecho y su profundidad varió significativamente (F = 5.53, P < 0.05; T = 3.04, P < 0.05; T = 2.57, P < 0.05) entre HJ y HV, respectivamente. Sin embargo, la abundancia de la macrofauna fue semejante entre las tres condiciones estudiadas (HV, HV y VM). De acuerdo a las variables edáficas estudiadas se encontró que la condición de HV no está degradada y que incluso presenta condiciones favorables para llevar a cabo acciones de restauración/rehabilitación.

There is considerable controversy with regard to the genotoxicity of glyphosate, with some reports stating that this compound is non-toxic for fish, birds and mammals. In this work, we used the comet assay to examine the genotoxicity of glyphosate isopropylamine (0.7, 7, 70 and 700 µM) in human lymphocytes, erythrocytes of Oreochromis niloticus and staminal nuclei of Tradescantia (4430) in vitro and in vivo. Cells, nuclei and fish that had and had not been exposed to 5 mM N-nitrosodiethylamine (NDEA) were used as positive and negative controls, respectively. Significant (p < 0.01) genetic damage was observed in vivo and in vitro in all cell types and organisms tested. Human lymphocytes and Tradescantia hairs showed lower genetic damage in vivo compared to in vitro, possibly because of efficient metabolization of the herbicide. In O. niloticus erythrocytes, significant (p < 0.001) genotoxicity was observed at > 7 µM, whereas in vitro, glyphosphate was genotoxic in human lymphocytes and Tradescantia hairs at > 0.7 µM. These results indicate that glyphosate is genotoxic in the cells and organisms studied at concentrations of 0.7-7 µM.