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NUEVOS REGISTROS EXTIENDEN DISTRIBUCIONES DE TRES ESPECIES DE HYMENOPHYLLACEAE (PTERIDOPHYTA) A LA REGION DEL MAULE, CHILE
No full textThis article reports the occurrence of three species of Hymenophyllaceae in the coast range of the Maule region in central Chile. The discovery of Hymenoglossum cruentum (Cav.) K. Presl., Hymenophyllum darwinii Hook.f. ex Bosch y Trichomanes exsectum Kunze at the Fundo San Pedro/ Las Cañas (35°29'S - 72°22'W) represents sizeable extensions of the known ranges of all three ferns, which are mainly associated with humid temperate forests further south. These findings provide further evidence that humid gully habitats in the Mediterranean climate of central Chile harbour many elements of the temperate rainforests which currently dominate landscapes further south
Hongos liquenizados en morrenas del monte San Lorenzo, Región de Aisén, Chile
No full textEn el presente trabajo se reportan 30 especies de hongos liquenizados presentes en morrenas de la parte occidental del Monte San Lorenzo en la Región de Aisén, Chile. Se destaca la presencia de Rhizocarpon lecanorinum Anders, nuevo registro para Chile continental
Modelos agroforestales en zona de secano. Región de Coquimbo
No full textEn el presente folleto se explican los ensayos establecidos para evaluar la intervención de sectores del secano con
modelos agroforestales-OCAS y los principales resultados y conclusiones obtenidos en el marco de este respecto
Ecofisiología de tallos jóvenes (cladodios) de Opuntia ficus-indica en condiciones húmeda y seca
No full textLas tasas de asimilación neta de CO2 fueron medidas cada 2 h por 24 h en tallos jóvenes (cladodios) de Opuntia ficus-indica (L.) Miller que estaban regados o expuestos a sequía en la primavera. También fue registrado el contenido relativo de agua. Los cladodios jóvenes mostraron metabolismo ácido de las crasuláceas (MAC). La sequía en la primavera redujo la asimilación neta diaria de CO2 y el riego la mantuvo. El ambiente seco afectó a la expresión de las fases de MAC reduciendo la asimilación de CO2 al final de la tarde (fase IV de MAC) más que por la mañana temprano (fase II) o por la noche (fase I). Los cladodios jóvenes mantuvieron valores positivos de ganancia de carbono en la primavera: no obstante su escasa cantidad de parénquima de almacenamiento de agua. Los cladodios jóvenes mostraron recuperación rápida de la fotosíntesis y en el contenido relativo de agua en respuesta la escasa lluvia que interrumpió la sequía al final de mayo. La tasa instantánea de asimilación de CO2 y la ganancia diaria de carbono de los cladodios jóvenes aumentaron significativamente en junio: después de que las plantas recibieron una cantidad sustancial de lluvia. La eficiencia fotosintética de cladodios jóvenes es cercana a los valores observados en cladodios maduros
Detección de albinismo en la regeneración de Persea lingue y Cryptocarya alba procedente del cerro Cayumanque, Región del Biobío, Chile
No full textABSTRACT As part of the ecological restoration of the Cerro Cayumanque, affected by a fire in 2012, seeds of native species were collected for plant production in nursery and posterior introduction. Here, albino seedlings of Cryptocarya alba and Persea lingue were detected. This is the first report of detection of a lethal mutation such as albinism within the regeneration of Chilean native species. In C. alba 5% of albinism and 0,1% in P. lingue were detected among seedlings
Caracterización cromosómica de Rhodolirium laetum (Phil.) Ravenna (Amaryllidaceae) a través de cariotipificación e hibridación in-situ de ADN ribosómico
No full textABSTRACT Rhodolirium laetum (Phil.) Ravenna has a karyotype 2n = 2x = 16 and the haploid formula 4m + 2sm + 2st. One pair of rDNA 45S signals and two pairs of rDNA 5S were detected through fluorescent in-situ hybridization. The results are discussed in the context of Traubiinae
THE ROLE OF COTRIC ACID AS A PHOSPHORUS MOBILIZATION MECHANISM IN HIGHLY P-FIXING SOILS
No full textExudation of low molecular weight carboxylates is an important phosphorus (P) acquisition strategy for plants in strongly P-fixing soils. The effect of citrate exudation on P availability was studied in five acid soils with a large organic matter content and a low available P pool. The amount of molybdate reactive P extracted by citric acid 10 mM (0.1-2 mg kg-1) was larger than the molybdate reactive P (MRP) extracted by CaCl2 10-3 M (0.007-0.07 mg kg-1). Both extractants were adjusted to soil pH prior to extraction. Also, the total P content of citric acid extracts (2-44 mg kg-1) far exceeded the total P content of CaCl2 (0.2-1.5 mg kg-1). However, ratios of MRP to total dissolved P (TDP) remained constant. When citric acid was added to the CaCl2-extracts (the pH of citric acid being adjusted to the pH of CaCl2, and thus eliminating release of P through acidification) a significant pH increase was noted. Simultaneously, MRP increased significantly in all but one soil. This suggests that the P availability enhancing properties of citric acid are not only due to acidification of the plant rhizosphere, but also to its Al and Fe complexing capacit
The history of rainfall data time-resolution in a wide variety of geographical areas
No full textCollected rainfall records by gauges lead to key forcings in most hydrological studies. Depending on sensor type and recording systems, such data are characterized by different time-resolutions (or temporal aggregations), t(a). We present an historical analysis of the time-evolution of t(a) based on a large database of rain gauge networks operative in many study areas. Globally, t(a) data were collected for 25,423 rain gauge stations across 32 geographic areas, with larger contributions from Australia, USA, Italy and Spain. For very old networks early recordings were manual with coarse time-resolution, typically daily or sometimes monthly. With a few exceptions, mechanical recordings on paper rolls began in the first half of the 20th century, typically with t(a) of 1 h or 30 min. Digital registrations started only during the last three decades of the 20th century. This short period limits investigations that require long time-series of sub-daily rainfall data, e.g, analyses of the effects of climate change on short-duration (sub-hourly) heavy rainfall. In addition, in the areas with rainfall data characterized for many years by coarse time-resolutions, annual maximum rainfall depths of short duration can be potentially underestimated and their use would produce errors in the results of successive applications. Currently, only 50% of the stations provide useful data at any time-resolution, that practically means t(a) = 1 min. However, a significant reduction of these issues can be obtained through the information content of the present database. Finally, we suggest an integration of the database by including additional rain gauge networks to enhance its usefulness particularly in a comparative analysis of the effects of climate change on extreme rainfalls of short duration available in different locations
Nuevos registros de hepáticas (Marchantiophyta) para la Región de Los Ríos, Chile
No full textFifteen new regional and one new provincial record are reported for Los Ríos Region, Chile. Notes on the geographical distribution and specimen data are provided for each taxon
COMPARATIVE MORPHOLOGY AND ANATOMY OF THE LEAF AND STEM OF PEPEROMIA DAHLSTEDTII C.DC., OTTONIA MARTIANA MIQ. AND PIPER DIOSPYRIFOLIUM KUNTH (PIPERACEAE)
No full textThe genera and species of Piperaceae show a considerable structural diversity of leaves and especially stems. This paper presents a comparative morphological and anatomical study of the leaves and stems of three common Brazilian species of this family (Peperomia dahlstedtii C.DC., Ottonia martiana Miq. and Piper diospyrifolium Kunth), the vegetative organs of which have previously been little studied. The collected plant material was fixed in FAA, cut freehand and stained in safranin and astra blue. P. dahlstedtii is an epiphyte and has a herbaceous stem with whorled leaves phyllotaxis and a polystelic structure, a multiseriate adaxial leaf epidermis and calcium oxalate monocrystals in parenchyma and collenchyma petiole cells. O. martiana and P. diospyrifolium showed strong similarities, both being terrestrial plants, with alternate phyllotaxis, stele with medullary bundles and dorsiventral leaves with an epidermis and subepidermic layer. In O. martiana the stomatal complex is staurocytic and presented silica crystal sand in parenchyma petiole and midrib cells. In P. diospyrifolium the stomatal complex is tetracytic and there are calcium oxalate raphide crystals in the parenchyma of the petiole and midrib cells. On the other hand, the three species show some structural likenesses in that all have hypostomatic and dorsiventral leaves, oily cells in petiole and mesophyll, secretory trichomes and an endodermis with Casparian strips