Efecto de la cobertura y de la fertilización en el desarrollo de plantas de Nothofagus alessandrii cultivadas en contenedor

Mena, C (Mena, Carlos).Univ Talca, Fac Ciencias Forestales, Ctr Geomat, Talca, Chile.Nothofagus alessandrii is an endangered species. Yet, available information for the propagation and nursery cultivation of this species is conspicuously lacking. To this end, we studied the effect of cover and fertilization on early growth of nursery seedlings over one growing season. Using a split plot experimental design with completely random fixed-effect blocks we monitored seedling growth with three levels of shade (plastic net Raschel (R) of 35, 50, y 80 %) and three doses of slow-release fertilizer (4, 6, and 10 g of Osmocote (R) per litter of growth media). Results demonstrated a significant effect of shade treatments on seedling development. Differences between seedlings treated with 35-50 % when compared with those treated with 80 % cultivated were observed on the evaluated attributes. In general, fertilization did not affect seedling development. In conclusion, it is more efficient to cultivate N. alessandrii nursery seedlings at 35 % shade and 4 g L-1 fertilization. Under this scenario, it is possible to produce plants, on average, with 28 cm in stem length; 4 mm of root collar diameter; 3.2 g plant(-1) total biomass; and quality indices of 6.9 (slenderness), 2.2 (root-shoot), and 2.1 (Dickson)

Considering Intra-individual Genetic Heterogeneity to Understand Biodiversity

In this chapter, I am concerned with the concept of Intra-individual Genetic Hetereogeneity (IGH) and its potential influence on biodiversity estimates. Definitions of biological individuality are often indirectly dependent on genetic sampling -and vice versa. Genetic sampling typically focuses on a particular locus or set of loci, found in the the mitochondrial, chloroplast or nuclear genome. If ecological function or evolutionary individuality can be defined on the level of multiple divergent genomes, as I shall argue is the case in IGH, our current genetic sampling strategies and analytic approaches may miss out on relevant biodiversity. Now that more and more examples of IGH are available, it is becoming possible to investigate the positive and negative effects of IGH on the functioning and evolution of multicellular individuals more systematically. I consider some examples and argue that studying diversity through the lens of IGH facilitates thinking not in terms of units, but in terms of interactions between biological entities. This, in turn, enables a fresh take on the ecological and evolutionary significance of biological diversity

Índices de área verde y cobertura vegetal para la ciudade de Parral (Chile), mediante Fotointerpretación y GIS

Mena, C (reprint author), Univ Talca, Fac Cs Forestales, Avda Lircay S-N, Talca, Chile.he importance of the green areas is increasing since they are an important factor in the health and welfare of urban population. Therefore, in Parral city, in Central Chile, it was quantified and analyzed the availability of green areas and vegetation cover, using aerial photographs scale 1: 10000 and Geographic Information Systems (GIS). In a first stage, urban street trees were quantified through a simple random sample of twenty-four units with field measurements combined with measurements on aerial photographs, from which it was obtained the surface provided. Subsequently, through the creation of GIS layers, the surface of existing green areas and available open spaces were obtained. In addition, through supervised digital classification, the surface covered by urban forestry in private spaces was calculated. Quantity indexes show that Parral city currently has 12.72 ha of green areas, equivalent to 4.82 m(2)/hab, which implies a green area frequency of 0.022 m(2)/m(2). These values could be improved, if the available open space are incorporated and thereby reach 12.06 m(2) per inhabitant. In relation with availability indexes it was established that the average of accessibility to a green area is 327.2 m. Moreover, assuming a buffer of 200 m around the green areas, it was determined that there are 5160 houses with the basic service (56.4%). By incorporating the available open spaces, these values decrease significantly obtaining an average of accessibility to a green area of 213.7 m and coverage of basic service of 79.2%. Finally, it was estimated that the existing vegetation within the urban blocks (urban forest in private spaces) represents an important resource 17.8 times larger than urban street trees, so it should be considered within the municipal plans and policies

Changes in drought tolerance of Pinus radiata in Chile associated with provenance and breeding generation

International audienceAbstractKey messageIn Chile, breeding radiata pine for growth has led to drifts in the degree of drought tolerance of the seedlings. Interior provenances gained a larger tolerance to drought after three breeding generations as shown by larger survival and root/shoot ratio under water shortage, while coastal provenance displayed an opposite trend.•Context Given that rainfall is predicted to decrease and to affect establishment and early survival of radiata pine (Pinus radiata D. Don) in Chile, there is a need to identify more drought tolerant genotypes at seedling stage.•Aims The aim of this study was to test whether provenances of P. radiata originating from interior or from coastal provenances, displayed different responses to short-term water shortage, and whether these responses differed from the first to the third breeding generation.•Methods Three generations of breeding families from two sites in Central Chile were compared. The seedlings were grown during 100 days and subjected to two watering regimes for 45 days. Survival, growth, and biomass allocation to roots and shoots were recorded.•Results The two provenances displayed different responses to drought. Biomass allocation to shoots and survival were significantly reduced by water shortage. The first generation seedlings from the coastal provenance displayed a larger survival rate when exposed to water shortage (i.e., 60 %); this rate decreased in the following breeding generations. On the contrary, the survival rate increased from the first to the third generation in the interior provenance.•Conclusions We observed an important local adaptation to water shortage in the interior provenance. This response may be due to the fact that parent tree populations of the interior provenance have successfully adapted to sites with periodic drought

Fecundity, spore recruitment and size in Gelidium sesquipedale (Gelidiales,Rhodophyta)

Gelidium sesquipedale fecundity was quantified by counting tetrasporangial sori and cystocarps per meter squared and by estimating the number of spores contained inside them . These were obtained by regression on a size metric of reproductive structures . Tetrasporangial sori length and cystocarp thickness were the best estimators of spore number. To assess spore recruitment, 12 pottery tiles were fixed to the bottom, and the appearance of small fronds was monitored. No clear seasonal pattern of reproduction was found . Tetraspore production peaked in March 1990 with 10.4 x 106 spores m-2, whereas the carpospore peak was lower, 4.9 x 10 5 spores m-2 in July 1989. Recruitment followed tetraspore peaks . The probability of a G. sesquipedale tetraspore making the transition to a recruit was 4.7 x 10-5. Frond length was significantly related to tetrasporangial sori number, while cystocarp number was only related to frond branching order. Minimum size for reproduction was 6.9 cm for gametophytes and 5.4 cm for tetrasporophytes; very rarely were cystocarpic fronds smaller than 9 cm, while tetrasporic fronds were often longer than 15 cm . Cystocarpic fronds were significantly shorter and had more branches than tetrasporic fronds

Modelo de planificación agregada para proyectos de fabricación/instalación de muros cortina

Este trabajo presenta un modelo de planificación agregada para la optimización de la producción e instalación de una empresa fabricadora de Muros Cortina, también llamados Sistemas de Fachada Ligera. Este producto está compuesto por una estructura de aluminio que se ubica por delante de la estructura de los edificios, sobre la cual se acoplan cristales. El objetivo de este estudio es diseñar un modelo de planificación agregada, que le permita a la empresa alcanzar mejores rendimientos en su actividad y la elaboración de presupuestos de buena calidad. De tal manera que los presupuestos diseñados se ajusten a los costos y operaciones reales, entregando como resultado las decisiones operacionales que se deben tomar para alcanzar las metas de la empresa. Para determinar algunos parámetros del modelo se recurrió al estudio de tiempos con cronómetro. Gracias a la implementación del modelo propuesto, se mejoró la planificación de la producción y la calidad de los presupuestos para participar en licitaciones.This paper presents a model of aggregate planning for the optimization of production and installation of Curtain Walls in a manufacturing company. This product is made out by a aluminum structure with crystal that it is installed in front of the buildings. The objective of this study is to design a model of aggregate  planning, that it allow finding better performances in the company activity, and allow elaborating good-quality budgets. In order that the designed budgets fit to the costs and real operations, giving up the operational decisions that should be done, in order to achieve the company goals. In order to determine some parameters of the model, times’ study with chronometer was used. Thanks to the implementation of the proposed model, the planning of production and the quality of the budgets got better

Chimerism in Wild Adult Populations of the Broadcast Spawning Coral Acropora millepora on the Great Barrier Reef

Chimeras are organisms containing tissues or cells of two or more genetically distinct individuals, and are known to exist in at least nine phyla of protists, plants, and animals. Although widespread and common in marine invertebrates, the extent of chimerism in wild populations of reef corals is unknown.The extent of chimerism was explored within two populations of a common coral, Acropora millepora, on the Great Barrier Reef, Australia, by using up to 12 polymorphic DNA microsatellite loci. At least 2% and 5% of Magnetic Island and Pelorus Island populations of A. millepora, respectively, were found to be chimeras (3% overall), based on conservative estimates. A slightly less conservative estimate indicated that 5% of colonies in each population were chimeras. These values are likely to be vast underestimates of the true extent of chimerism, as our sampling protocol was restricted to a maximum of eight branches per colony, while most colonies consist of hundreds of branches. Genotypes within chimeric corals showed high relatedness, indicating that genetic similarity is a prerequisite for long-term acceptance of non-self genotypes within coral colonies.While some brooding corals have been shown to form genetic chimeras in their early life history stages under experimental conditions, this study provides the first genetic evidence of the occurrence of coral chimeras in the wild and of chimerism in a broadcast spawning species. We hypothesize that chimerism is more widespread in corals than previously thought, and suggest that this has important implications for their resilience, potentially enhancing their capacity to compete for space and respond to stressors such as pathogen infection

Quince (Cydonia oblonga) in vitro plant root formation through an automated temporary inmersion system, and its acclimation

Artículo científicoQuince (Cydonia oblonga) is a non-traditional fruit tree found in Costa Rica that has therapeutic and nutritional properties; however its slow growth and root formation prevents the production of a homogeneous population when using conventional farming techniques. Hence, the aim of this research project was to generate uniform plant material in a reduced time span using a temporary immersion bioreactor system (RITAS ®). A semisolid rooting MS culture medium supplemented with 0.1 mg L-1 NAA; 0.3 mg L-1 IBA and 3% sucrose (pH 6.5), developed in the Centro de Investigación en Biotecnología (CIB), Instituto Tecnológico de Costa Rica (ITCR), in Cartago, was used as a reference medium. Four different variations in the sucrose concentration (1%, 2%, 3%, and 4%) were performed in liquid medium. Each trial was evaluated with in vitro plants which had been previously exposed to the culture medium of the corresponding treatments, in a stationary mode and for a 15 day long period, and with in vitro plants without any previous treatment (a total of eight treatments). The comparison of the root formation percentages evidenced the clear effect of sucrose concentration used, with the best results obtained when using the 2% sucrose trial with no pre-treatment (73.3%). The in vitro plants were acclimated in cylinders made out of peat, have previously been disinfected with fungicide, and placed in a humidity chamber at a 20.5°C average temperature and a 75,5% relative humidity for the establishment of weekly fertilizing cycles. The acclimation process generated an 80% survival rate, since several seedlings experienced stem strangulation caused by a fungal attack. The conidiophores identified through optical and scanning electron microscopy evidenced the presence of Cladosporium spp., which was controlled with carbendazim and iprodione fungicides

Recruitment Potential of a Green Alga Ulva flexuosa Wulfen Dark Preserved Zoospore and Its Development

The recruitment potential and the ability of Ulva flexuosa Wulfen zoospores to survive darkness were tested under different conditions in the present study. The dark preserved zoospore was cultured under a two-factor experimental design to test the effect of salinity and nitrate, effect of salinity and phosphate, effect of light and salinity, and effect of light and phosphate. The recruitment (germination and growth) of zoospores was significantly affected by light and salinity. The nitrate concentration of 20 µmol.l−1 was found to initiate the process of germination and its subsequent growth and, its effect appeared greatest under 25 psu condition. While nitrate enhances the growth of biomass more than phosphate, both show a positive interactive effect on biomass increase when crossed with salinity. The combined effect of 25 psu salinity and 8 µmol.l−1 phosphate exhibited higher biomass growth. There was a significant effect of light and salinity on the biomass of zoospore, though there was no significant interaction between the two factors. There was an increase in biomass of growing zoospores to increase in light intensity and 80 µmol.m−2.s−1 of light intensity was considered optimal. Similarly, high light intensity condition favored higher biomass growth and there was significant interaction between light (80 µmol. m−2. s−1) and phosphate (4 µmol. l−1) in high salinity (35 psu) condition. The result of this study showed that dark preserved zoospores of U. flexuosa have the potential for recruitment and it gives us an understanding how different factors play a role in the process of recruitment