Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Lygodium sp. is a climbing fern that occurs in open forests, settling frequently in areas with disturbed vegetation. In Argentina, Lygodium venustum inhabits in the protected area "Moconá" Provincial Park, in few and small populations. In-vitro cultivation of spores is a strategy for ex-situ conservation of species with reduced or threatened populations. Usually, fern spores need to be surface sterilized before sowing, to avoid the development of unwanted microorganisms. As part of our project focused on the conservation of native fern species in Argentina, the aim of this work was to evaluate a propagation protocol for L. venustum through in-vitro cultivation of spores, employing a standard procedure of disinfection, to investigate its effect on spore germination and the subsequent gametophyte as well as its response by the inoculation with a fungus. A batch of spores was previously treated with 10% (v/v) solution of NaOCl during 2 min and then sown in Dyer agar medium supplemented with 1% Nystatin (T1). The petri dishes were incubated in a growth chamber under white illumination (28μmol m-2 s-1) with a photoperiod of 12 hr and a temperature of 22±2°C. Another set of spores without previous disinfection was sown on Dyer agar medium and under the same conditions and used as a control (T0). Spore germination and gametophyte and sporophyte development were monitored through periodical observations under stereoscopic and light microscopes. As during cultures of non-disinfected spores a fungus developed in association with L. venustum gametophytes, its conidia were morphologically characterized as well as those obtained from the black spots present on the sporophyte leaves. A conidial suspension was applied to 20 days-old gametophytes obtained in axenic conditions to evaluate the appearance of any symptom. In both treatments (T1 and T0), spores germinated at 7 days after sowing. The pattern of spore germination followed the Anemia-type, unlike the Vittaria-type found by other researchers. Untreated spores showed a higher mean percentage of germination than those treated (86 and 72 % in 30 days, respectively). In T0 gametophytes grew in association with a fungus, whose conidia had the morphological characteristics of Pestalotiopsis maculans, as occurred with the conidia obtained from the black spots of L. venustum leaves. The association of P. maculans with L. venustum is reported here for the first time. The gametophytes developed in T0 and those inoculated with P. maculans became necrotic and died before producing gametangia, suggesting a pathogenic role of the fungus. The elevated percentage of spore germination registered in T0 could also indicate some effect of P. maculans or its metabolites in the promotion of spore germination. Gametophytes developed in T1 became bisexual or unisexual male, which points to the presence of some antheridiogen that induces the production of antheridia on smaller or slower-growing gametophytes. The sporophytes arose after 4 months of spore sown in T1, pointing out the methodology employed here suitable for the ex-situ conservation of L. venustum.

The oil industry has generated chronic spills and its accumulation in the mangrove forest located on the southeast coast of Mexico. The evaluation of the impact of oil on the soil-root interaction of Languncularia racemosa (Lr) is basic to determine the changes in microbial activity and its biotechnological potential for land remediation. Lr is a tree that grows in these areas contaminated with weathered oil. The objective of this study was to evaluate the spatial distribution in soil of total petroleum hydrocarbons (TPH), the population of plant growth promoting bacteria, microbial respiration in the rhizoplane (RI), rhizosphere (RZ) and non-rhizospheric soil. (SNR) of Lr. For this study, an area of ​​8,000 m2 of a Histosol affected by chronic oil spill and drilling mud from the La Venta 248 oil well was used. Fifteen Lr trees were selected and samples were taken from the RI (secondary roots), from the RZ (secondary and tertiary roots with adhered soil) and SNR (organic matter). The results show differences in the amount of HTP accumulated in the organic soil. The spatial distribution of the HTP defined four study floor (S): S1: 1797, S2: 3294, S3: 5249, and S4: 10389 mg kg-1. The PHT were higher in RI of S1 and 2, but in RZ and SNR in S2 and 3. In RI of Soil 4 the population of N-fixing and P-solubilizing bacteria were stimulated in greater quantity, but Azotobacter was inhibited and Azospirillum. For the RZ of Lr Azospirillum it was favored but in the soil 2 and 4. The microbial respiration at 7, 14, 21, 42 and 63 days was stimulated by the IR followed by the RZ in the four evaluated soils, however the respiration microbial was negatively affected by oil in the RI, RZ and SNR. The results suggest that Lr is sustainable in soils with hydrocarbon contamination, and is a biostimulator of microbial activity that can be used for the natural attenuation of hydrocarbons, with a high population of N-fixing bacteria and solubilizers of P in RI with 10389 mg kg-1 of HTP derived from weathered petroleum. However, soils containing HTP higher than 4158 mg kg-1 in RI, RZ and SNR require previous treatment to remove the oil and put it in contact with the RZ of the white mangrove.

Abstract: Reunion in the overseas: introduced wild boars and cultivated orange trees interact in the Mata Atlântica (Brazil). Novel interactions are attracting a lot of interest, especially those occurring between wild animal species and agricultural crops as a consequence of human activities. Novel interactions usually concern to species that interact only because human activity but that otherwise would not even coexist. Typically novel interactions arise from biological invasions as well as from interactions between native and crop species. Less studied are novel interactions between species that originally interact in their native range but, as consequence of human activity (domestication, game introductions, etc.), are now interacting out of their original distribution under new ecological conditionsIn this article, we study the interaction between orange and wild boar, both species sharing Asian origin but being introduced in America and then subjected to new ecological conditions. Dispersers of sweet orange seeds are unknown. As wild boar consumes fruits frequently in citrus orchards, here we assessed whether i) it consumes orange seeds, ii) they are viable after passing through boar’s digestive tract and iii) orange seedlings may naturalise in the Mata Atlântica of Brazil, in a citrus farm surrounded by a large natural area called Mata da Virgínia. We used camera surveys in the orange orchards and in the jungle to identify orange fruit consumers in two periods in 2014 and 2015. The jungle was additionally surveyed looking for citrus seedlings finding more than 50 seedlings in which it was confirmed that they belong to sweet orange trees by SSR techniques. As the wild boar was identified as the main orange consumer, 19 fresh boar feces were collected and citrus seeds removed and sown to assess their viability. Citrus seeds were also planted in the jungle and their germination and seedling survival were studied. Three years after sowing, just 5% of the seedlings remained alive with an average height of less than 10 cm.

The life history of the California sea lion (Zalophus californianus) in the Gulf of California is marked by a series of important events influencing and modifying its population growth, distribution, and evolution. Despite the fact that this population has been studied since the 1950s, research has been rather punctual and fragmentary. Before 2010, there are only a few surveys conducted simultaneously in all rookeries, thus there is no reliable information on key aspects of life cycle, population trend and potential threats. In the present work we conducted a review of California sea lion life history and environmental changes in the Gulf of California thorough a collation survey data encompassing the last 37 years. Objective: Our aim was focused on identifying short- and long-term processes potentially acting on the population, and hopefully improve knowledge about the population trend and status using different points of view. Methods: We collected and analyzed population survey data from different sources since the 1970s to 2018: published papers, master’s and doctoral thesis, in addition to technical reports. The survey data are organized in sections corresponding with crucial population life history events. Results: Considering a long-time period the population size appears to be stable with zero growth. Cyclic interannual fluctuation seem to denote a certain dependence with climatic factors, not directly with El Niño, but with sea surface temperature anomalies that determine prey availability. However, many doubts persist about the incidence of different local environmental factors on gender and age, particularly related with juvenile recruitment and female survival rate. Conclusions: In conclusion, more information is required based on seasonal surveys, life cycle, regional environmental variation. Statistical errors need to be assessed and monitoring methods should be standardized and must be considered to ascertain short- and long-term population and colony spatial-temporal patterns.