MORPHOLOGY OF FLORAL STRUCTURES RELATED TO ANTITELECHORY DISPERSAL OF FRUITS IN Tagetes moorei H. Rob. var. breviligulata Villarreal
MORFOLOGÍA DE ESTRUCTURAS FLORALES RELACIONADAS CON LA DISPERSIÓN ANTITELÉCORA DE FRUTOS EN Tagetes moorei H. Rob. var. breviligulata Villarreal
/ pages 261 -269
Tagetes moorei var. breviligulata (Asteraceae-Tageteae) is an endemic species from Queretaro, Mexico. This species is found in some semiarid areas and grows on calcareous soils. Biological and ecological background of this species is scarce. This paper describes some aspects of the plant morphology of T. moorei, particularly at the flower head level, related to a special mechanism for seed dispersal classified as autochore-antitelechore. In this mechanism, the achenes formed in the involucre do not fall directly to the ground during dehydration and flower head drying, as with most Tagetes species. In this case, flower pedicel is collapsed and separates from the involucre; then achenes slid inside the peduncle. This seed dispersal mechanism in semiarid environments is uncommon for Asteraceae.
METHODS TO DETERMINE ECOTOUHRISM SUITABILITY OF FOREST AREAS
MÉTODOS PARA DETERMINAR LA APTITUD ECOTURÍSTICA DE ÁREAS FORESTALES
/ pages 271 - 289
Any ecotourism initiative must be based on the biophysical characteristics that exist in the zone and the environmental suitability to sustain its activities. Several studies have proposed methodologies to define the suitability for such purpose, however, only a few of them have approached a compara¬tive analysis in order to determine its practical usefulness. The aim of this study was to analyze the methods used when determining the ecotourism suitability of forest areas as a reference for future works. It was observed two types of methods: qualitative (which describe the information related to the problem under study) and quantitative (which focus on measuring variables and the application of statistical processes to their analyses). The latter approach has more advantages over the former one as it allows characterizing the ecotourism activity of interest through natural, economical and social criteria, and associated indicators such as topography, vegetation, hydrography, geology, proximity to settlements and infrastructure. Furthermore, quantitative methods are the most desirable for evaluat¬ing ecotourism suitability because they generate a suitability value for comparative purposes. Knowing both methodological approaches provide guidance for future assessment on this topic.
ESTIMATED DECOUPLING OF Agave cupreata POPULATIONS TO THEIR SUITABLE HABITAT DUE TO CLIMATE CHANGE
ESTIMACIÓN DE LA DISOCIACIÓN DE Agave cupreata A SU HÁBITAT IDÓNEO DEBIDO AL CAMBIO CLIMÁTICO
/ pages 291 - 301
Mature individuals of Agave cupreata are harvested to produce an artisan distilled alcoholic beverage (mescal). The objective of this study was to estimate the potential decoupling of suitable habitat due to climatic change, between the populations and the climate for which they are adapted. Therefore, the contemporary (average 1961-1990) and future (decade centered in the year 2030) climate for 12 localities was estimated, where natural populations are distributed, using a spline climate model, based on outputs from the Canadian General Circulation Model and intermediate emission scenario A1B. Average temperature estimates of the 12 provenances for contemporary climate was 19.1 °C and precipitation estimates was 961 mm. Predicted for year 2030 was 20.5 °C and 833 mm, with a temperature increment of 1.4 °C and a precipitation decrease of 13.3 %. Results indicate that sui¬table climate for A. cupreata will occur at 175 to 225 m of higher elevations than the locations were populations are presently. Therefore, It is suggested to establish ex situ conservation and commercial plantations under the conditions mentioned above, as assisted migration management measure for adaptation to the predicted climatic change.
ROOT BIOMASS IN A TEMPERATE FOREST WITH AND WITHOUT FOREST MANAGEMENT IN HIDALGO, MEXICO
BIOMASA DE RAÍCES EN UN BOSQUE TEMPLADO CON Y SIN MANEJO FORESTAL EN HIDALGO, MÉXICO
/ pages 303 - 312
The effect of forest management on biodiversity and ecosystem processes has been little studied in Mexican temperate forests. In this way, roots are good functional indicators of an ecosystem because they constitute much of the living ground biomass and exert control over soil formation processes, organic matter production and nutrient dynamics. This study compares coarse and fine root biomass from a protected forest and a managed area where there was selective logging during 2003 and 2004, resulting in the removal of 10 % of the trees. The average root biomass did not differ significantly between sites (P = 0.185). Root biomass in the managed forest was 3.05 Mg·ha-1 (S.E. = 0.25) and 3.39 Mg·ha-1 (S.E. = 0.24) in the preserved forest. Fine roots occupied the highest percentage of the biomass in both forest types, although their values did not differ significantly between sites (P = 0.095). As the results suggest, selective logging maintains environmental conditions, particularly those of the soil, which allows having similar biomass to that in the forest preserved under natural conditions.
CONTROLLED RELEASE FERTILIZERS APPLIED TO Pinus radiata D. DON IN CHILE
FERTILIZANTES DE LIBERACIÓN CONTROLADA APLICADOS AL ESTABLECIMIENTO DE Pinus radiata D. DON EN CHILE
/ pages 313 - 328
The use of controlled release fertilizers (CRF) is emerging and there are no published results for their use in Chile. In this study, it was evaluated the use of a CRF at the time of establishment of Pinus radiata on an ultisol in Valdivia, Chile. The study was conducted in three different sites with soil varia- tions (2006). Six CRF, a traditional water-soluble fertilizer and a control treatments were applied (10-20 g·plant-1). Data were analyzed in a randomized block design. The evaluation (2006- 2010) considered survival, tree growth and weed covers. The survival was between 84 and 96 %, with no difference between treatments (P > 0.05). The CRF growth responses were higher than the control and similar to the water- soluble fertilizer. The highest yields of the trees during the fourth year were obtained with the CRF use (+42% input). The CRF gave better response with higher doses or more prolonged release periods. The response was different between sites, in both, soil structure and its nutrient supply. The growth was diminished with a weed cover higher than 30 % in the plantation.
INCIDENCE OF INSECT PREDATORS ON ORCHIDS AT THE LAS JOYAS RESEARCH STATION, JALISCO, MEXICO
INCIDENCIA DE INSECTOS DEPREDADORES SOBRE LAS ORQUÍDEAS DE LA ESTACIÓN CIENTÍFICA LAS JOYAS, JALISCO, MÉXICO
/ pages 329 - 339
The incidence of insect predators on orchids was evaluated in seven plots located at the Las Joyas Research Station (LJRS), Jalisco, Mexico. This research was conducted between September 2009 and February 2010. A total of 130 species from 16 orchid genera were identified. S. martiniana, C. pen- dula, O. tigrinum and R. splendens were the main host orchid species. All of them showed significant damages in their organs due to the incidence of phytophagous Hemiptera. M. lutem and A. spiraecola (Patch) were the phytophagous insect species that provoked major damage in orchids. Insects cau- sed significant damages in species located in anthropised areas. This assessment would improve the current conservation strategy of Orchidaceae in Jalisco.
IDENTIFICATION OF FUNGI POTENTIALLY ANTAGONIST TO Phytophthora cinnamomi Rands IN OAK FOREST AT THE EL ARRAYANAL, COLIMA AND TECOANAPA, GUERRERO
IDENTIFICACIÓN DE HONGOS ANTAGONISTAS A Phytophthora cinnamomi Rands EN BOSQUES DE ENCINO DE EL ARRAYANAL, COLIMA Y TECOANAPA, GUERRERO
/ pages 341 - 355
The aim of this study was to identify morphologically and molecularly the mycoflora that possesses antagonistic properties on Phytophthora cinnamomi associated to the oak (Quercus spp.) soil forest at El Arrayanal, Colima, and Tecoanapa, Guerrero. Two soil samplings were done in these sites. Soil -root samples around trees with different ages and health conditions in stands affected by P. cinnamo- mi were collected. The fungi were morphologically identified by soil dilution PDA-TS (potato-dextrose- agar-tergitol-streptomycin) technique. With the obtained isolates, in vitro antagonism tests were done. Trichoderma spp, Cordyceps bassiana and Paecilomyces isolates, showed the best biological control by reducing P. cinnamomi development and showing outstanding mechanisms of space competition and mycoparasitism. The fungi were molecularly characterized by amplifying the intergenic region (ITS) of the ribosomal genes by the amplification of polymerase chain reaction (PCR) technique. For the first time C. bassiana, Cladosporium tenuissimun and six Trichoderma species associated with oak forests in Mexico are reported.
GENESIS OF FOREST FIRES
GÉNESIS DE LOS INCENDIOS FORESTALES
/ pages 357 - 373
Forest fires began on our planet nearly 470 million years ago, during the Silurian Period. Their activity has experienced highs and lows throughout the Earth’s history, mainly related to the changes in the concentration of atmospheric oxygen and humidity levels that have characterized the evolution of the climate. High levels of wildfires were present during the Carboniferous, Jurassic and Cretaceous Pe- riods as well as in the Quaternary, with the appearance of man. The first fire adaptations took place at approximately the same time as the colonization of the earth by plants. With the separation of Pangea during the Triassic Period, the climate began to evolve toward the present patterns and thus define the annual forest fire seasons along with the configuration of fire regimes similar to those of the present.
CALORIFIC VALUE AND INORGANIC MATERIAL IN THE BARK OF SIX FRUIT TREES
PODER CALORÍFICO Y MATERIAL INORGÁNICO EN LA CORTEZA DE SEIS ÁRBOLES FRUTALES
/ pages 375 - 384
Calorific value and mineral matter (ash) content were determined in the bark of six fruit tree species (Annona cherimola Mill., Citrus aurantifolia Swingle, Malus domestica Borkh., Psidium guajava L., Prunus dulcis [Mill.] D. A. Webb and Tamarindus indica L.). Ashes obtained were analyzed by X- ray.The calorific values found ranged from 3,453.49 kcal·kg-1 in T. indica to 4,076.10 kcal·kg-1 in P. guajava. In the case of the ashes, the results ranged from 5.76 % in Psidium guajava to 21.93 % in Tamarindus indica. It was observed that a higher content of minerals in the bark tends to decrease its calorific value. The common chemical elements in the samples analyzed were calcium, potas- sium, magnesium, phosphorus and sulfur. No heavy metals were detected in the samples of the bark.
INSECTICIDAL ACTIVITY OF ESSENTIAL OILS FROM TwO Eucalyptus SPECIES ON Rhyzopertha dominica (COLEOPTERA: BOSTRIChIDAE) AND ITS EFFECTS ON DIGESTIVE ENZYMES OF PROGENIES
ACTIVIDAD INSECTICIDA DE ACEITES ESENCIALES DE DOS ESPECIES DE Eucalyptus SOBRE Rhyzopertha dominica Y SU EFECTO EN ENZIMAS DIGESTIVAS DE PROGENIES
/ pages 385 - 394
The volatile fraction of essential oils from Eucalyptus globulus and Eucalyptus camaldulensis was used to evaluate their effective insecticidal toxicity against the lesser grain borer Rhyzopertha domi- nica (F.). Wheat grain samples were infested with the beetle and exposed to the vapors of different volumes (5, 10 and 15 μL) of the essential oils for different periods (24, 48 and 72 h). Emerging adults from each wheat sample were counted and analyzed in terms of amylolytic and proteolytic activity. Both essential oils were effective at promoting high amylolytic and proteolytic activity in emerged prog- enies, but only E. globulus caused lethal effects on the progenies (P < 0.05). By increasing the volume of E. camadulensis oil, the proteolytic activity of the insect increased, even at longest exposure time. The results of this study show that the volatile fraction of the essential oils from eucalyptus, especially E. globulus, is an effective insecticidal agent for controlling R. dominica in stored wheat.
STRUCTURAL CHARACTERIZATION OF THE MANGROVE FOREST IN THE ESTERO PALO VERDE, CUYUTLÁN LAGOON, COLIMA
CARACTERIZACIÓN ESTRUCTURAL DEL MANGLAR EN EL ESTERO PALO VERDE, LAGUNA DE CUYUTLÁN, COLIMA
/ pages 395 -408
In the Estero Palo Verde, located in section IV of the Cuyutlán Lagoon, state of Colima, 48 sample units (SU) were established on three types of mangrove stands: 10 SU on pure stand of Laguncularia racemosa, 25 SU on pure stand of Rhizophora mangle and 13 SU on mixed forest stand of L. racemo- sa-R. mangle. Canopy height, trunk diameter, density of adults and natural regeneration were recor- ded, also basal area and tree volume were calculated. Results indicated that density, basal area and tree volume for diameter category (DC) of 5 cm were significantly (P < 0.05) different between the pure stands of R. mangle (2500 trees·ha-1, 4.2 m2·ha-1, 22 m3·ha-1) and L. racemosa (700 trees·ha-1, 1.9 m2·ha-1, 10 m3·ha-1). In the case of DC of 20 to 30 cm, the basal area was significantly (P < 0.05) higher in the pure stand of L. racemosa (1.6 – 3.8 m2·ha-1) than in the mixed forest stand of L. racemosa-R. mangle (0.5 – 2.5 m2·ha-1). Natural regeneration was more abundant in the stand of R. mangle (138 – 270 individuals·ha-1) than in the stand of L. racemosa (70 – 80 individuals·ha-1). The highest structural values were reached for canopy height (10 m) in the stand of L. racemosa, for trunk diameter (40 cm) and basal area (14.1 m2·ha-1) in the stand of L. racemosa-R. mangle, and for natural regeneration (624 individuals·ha-1) in the stand of R. mangle.
PLANT-ARBUSCULAR MYCORRHIZAL FUNGI INTERACTIONS
INTERACCIÓN PLANTA-HONGOS MICORRÍZICOS ARBUSCULARES
/ pages 409 - 421
Arbuscular mycorrhizal symbiosis is formed between the roots of over 80 % of all terrestrial plant species and Zygomycete fungi of the order Glomales. The beneficial effects of this symbiosis occur as a result of a complex molecular dialogue between the two symbiotic partners. Identifying the mole- cules involved in this dialogue is a prerequisite for a better understanding of the symbiosis. Although there is evidence for an interplay of signaling-recognition events at different stages during plant-fungal interactions in arbuscular mycorrhiza, the nature of signaling molecules and signal perception/trans- duction processes are still not known. To unlock the potential of arbuscular mycorrhiza for sustainable agriculture, we must identify the key molecular players. A number of methods are available for those researchers considering the addition of molecular analyses of arbuscular fungi to their research pro- jects and weighing the various approaches they might take. Increasingly powerful molecular methods for analyzing arbuscular communities make this area of research available to a much wider range of researchers.
DIET COMPOSITION AND NUTRITIONAL CARRYING CAPACITY OF THE HABITAT OF THE VOLANCO RABBIT (Romerolagus diazi) IN MEXICO
COMPOSICIÓN DE LA DIETA Y CAPACIDAD NUTRICIONAL DE CARGA DEL HÁBITAT DEL CONEJO DE LOS VOLCANES (Romerolagus diazi) EN MÉXICO
/ pages 423 - 434
The purpose of this study was to estimate the nutritional intake, plant biomass and the nutritional carrying capacity of the habitat of the volcano rabbit (Romerolagus diazi), plus its feeding habits, in Itza-Popo Zoquiapan National Park. Fecal pellets and plant samples were collected and analyzed microhistologi- cally. Dry matter, crude protein and neutral detergent fiber were determined in plants. Biomass and its nutritional carrying capacity were estimated. In turn, a digestibility assay was conducted with domestic rabbits using two treatments: Muhlenbergia macrura or Festuca tolucensis (80 % plus 20 % alfalfa hay). In half of the sites M. macroura was predominant and in the other half F. tolucensis; microhistiological analysis showed the predominant presence of the same forages. There were differences in biomass and carrying capacity among sites (P < 0.05), with one site standing out from the others. Inclusion of F. tolucensis increased (P < 0.05) digestibility compared to M. macroura.
ECONOMIC VALUATION OF URBAN WASTE RECYCLING
VALORACIÓN ECONÓMICA DEL RECICLAJE DE DESECHOS URBANOS
/ pages 435 - 447
In the present study, using the referendum contingent valuation method (RCVM), an economic valu- ation was carried out to implement a recycling system. For this, the population of the municipality of Texcoco was taken as a case study, to which a simple random sampling method, at the level of household, was applied with a confidence level of 95 %, resulting in a total sample of 402 house- holds. Results show that more than 90 % of heads of households are aware of the garbage problem. However, 70 % of respondents know very little about recycling and almost 100 % of them think it is necessary to set up a recycling system. Moreover, by applying the RECVM, and by adjusting a binary LOGIT model, a weekly willingness to pay (WTP) per house hold equal to $27.18 was esti- mated. As a result, total benefits of $1,295,915 were calculated per week. The model coefficients were estimated using maximum likelihood.
VALORIZATION OF TEQUILA AGROINDUSTRIAL RESIDUES FOR RUMINANTS FEEDING
VALORIZACIÓN DE RESIDUOS AGROINDUSTRIALES DEL TEQUILA PARA ALIMENTACION DE RUMIANTES
/ pages 449 - 457
The aim of this study was to investigate a suitable technology for the use of bagasse of Agave tequilana W. var. azul in food ratios for ruminants. Physical and chemical characteristics of ba- gasse were evaluated. According to these characteriztics, bagasse can be used as a supplement in ruminant feeding. However, an inconvenience is the low digestibility of bagasse, due to its high content of lignin, used to decrease this a calcium hydroxide treatment was used. The chemical treatment was conducted in a glass reactor (50 L) with the following conditions: concentration of Ca(OH)2 of 2, 5 and 10 %, bagasse humidity of 20 and 80 %, temperatures of 30 and 50 °C. Digestibility tests were conducted in chemically treated bagasse. The digestibility increased from 36 % (untreated bagasse) to 54.5 % with the best treatment (80 % moisture, Ca(OH)2 10 % and 50 °C). It can be concluded that the bagasse treated with Ca(OH)2 can be used as supplement in the composition of ruminants diet based on the digestibility results.