Acarofauna associated to papaya orchards in Veracruz, Mexico

Productores agrícolas en México recientemente notaron un fuerte incremento en las infestaciones de ácaros en las huertas de papayo (Carica papaya L. 1753). Se elaboró una lista de las especies de ácaros asociados con hojas de papayo para determinar las especies responsables de las altas infestaciones y para identificar a los ácaros depredadores. Los ácaros fueron colectados de tres estratos (alto, medio y bajo) en siete muncipios del centro del estado de Veracruz. Las hojas fueron procesadas por lavado y tamizado. Las especies identificadas incluyeron cuatro tetraníquidos: Eotetranychus lewisi (McGregor 1943), Eutetranychus banksi (McGregor 1914), Tetranychus merganser Boudreaux 1954 y Tetranychus urticae Koch 1836; tres fitoseidos: Euseius hibisci (Chant 1959), Galendromus helveolus (Chant 1959) y Phytoseiulus macropilis (Banks 1904), donde las dos primeras especies fueron las más abundantes. El ácaro eriófido errante Calacarus citrifolii Keifer 1955 fue colectado en tres municipios, en el estrato bajo. El ácaro blanco, Polyphagotarsonemus latus (Banks 1904), y el ácaro carmín, Tetranychus cinnabarinus (Boisduval 1867), no fueron colectados, aunque estas dos especies fueron registradas previamente en esta área. Ninguno de los fitoseidos encontrados puede ser considerado de reciente establecimiento en el área; se discute su potencial como agentes de control biológico

Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus

The photosynthetic responses to a flowering-inductive water-stress period and recovery were studied and compared in two Citrus species. Under greenhouse conditions, Fino lemon and Owari satsuma trees were subjected to moderate (-2 MPa at predawn) and severe (-3 MPa) water stress levels and were re-watered after 60 days. Vegetative growth was inhibited during the stress assays, and strong defoliation levels were reported, especially in Fino lemon. In both species, bud sprouting was induced after re-watering. Flowers and vegetative shoots developed in Owari satsuma after a drought period, and the development was independent of the stress level. In Fino lemon, vegetative shoots and flowers were primarily formed after moderate and severe stress, respectively. The photosynthetic rate and stomatal conductance were reduced by water stress, and a marked increase in water-use efficiency at the moderate water deficit level was observed. Nevertheless, the photosynthetic apparatus was not damaged, since the maximum quantum yield, photosynthetic pigment concentrations and Rubisco level and activity did not change. Furthermore, the measured malonyldialdehyde (MDA) and peroxidase activity indicated that oxidative stress was not specifically triggered by water stress in our study. Therefore, the gas exchange, fluorescence and biochemical parameters suggested that diffusional limitations to photosynthesis predominated in both of the studied Citrus species, and explained the rapid recovery of the photosynthetic parameters after rehydration. The net CO 2 fixation rate and stomatal conductance were recovered within 24 h in Fino lemon, whereas 3 days were required in Owari satsuma. This suggests the presence of some metabolic limitations in the latter species. Furthermore, the sensibility of the defoliation rates, the accumulation of proline and the stomatal behaviour in response to water stress indicated a higher drought tolerance of Fino lemon, according to its better acclimation to hot climates. © 2011 Springer-Verlag.The authors thank Dr. J. Moreno and co-workers from the Departamento de Bioquimica of the Universidad de Valencia for his help and support in the Rubisco assays, and Dr. F. Fornes, Dr. A. Calatayud and Dr. E. Primo-Millo for the critical review of the manuscript. This work was funded by the Universitat Politecnica de Valencia, Spain (Ayudas para primeros proyectos de investigacion PAID06-06).Ávila Reséndiz, C.; Guardiola Barcena, JL.; González Nebauer, S. (2012). Response of the photosynthetic apparatus to a flowering-inductive period by water stress in Citrus. Trees - Structure and Function. 26(3):833-840. https://doi.org/10.1007/s00468-011-0657-4S833840263Addicott FT (1982) Abscission. 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Arch Biochem Biophys 125:189–190Hoagland DR, Arnon DI (1950) The water culture method for growing plants without soil. California Agricultural Experiment Station Circular no. 347, p 32IPCC (2001) Climate change 2001. In: Houghton JT (ed) The scientific basis. Cambridge University Press, CambridgeLawlor DW (1995) The effects of water deficit on photosynthesis. In: Smirnoff N (ed) Environment and plant metabolism. Bios Scientific Publishers, Oxford, pp 129–160Lichtenthaler HK, Buschmann C (2001) Current protocols in food analytical chemistry, F4.2.1 and F4.3.1. John Wiley and Sons, Inc, NJLorimer GH, Badger MR, Andrews TJ (1977) D-Ribulose-1, 5-bisphosphate carboxilase-oxigenase. Improved methods for activation and assay of catalytic activities. Anal Biochem 78:66–75Miyashita K, Tanakamaru S, Maitani T, Kimura K (2005) Recovery responses of photosynthesis, transpiration, and stomatal conductance in kidney bean following drought stress. 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Sociocultural aspects of nourishment and the use of the plot in the rural community of Bandera de Juárez

Objective: To analyze sociocultural aspects related to human nourishment and the use of family plots in the community of Bandera de Juárez, Veracruz, México. Methodology: A literature review, together with open interviews and on-field participative observations, knowledge exchange workshops and life storytelling were made. Results: The celebration of the feasts of San Isidro Labrador and All Saints Day were identified as moments for the re-creation of identities and strengthening of links that constitute social networks. They represent major occasions for understanding different productive and sociocultural uses of plots. In these phenomena nourishment is an essential factor. The family plot agroecosystem as a space of social importance sets a socialization and identity development process. Implication: The process players generate awareness on the value of traditional nourishment, the nutritional quality thereof and the rescue of their cultural identity. Findings: The importance of how nourishment “feeds” cultural processes is outlined. Some useful concepts, both for understanding sociocultural aspects of nourishment, the handling and uses of the plot, as well as the justification for the choice of the research method are discussed

Agricultural credit use in papaya agroecosystems in the central region of Veracruz, Mexico

Objective: To analyze the use of agricultural credit and the profitability of their papaya agroecosystem. Design/methodology/approach: A survey was applied using a questionnaire to 114 producers in seven municipalities in the central area of Veracruz, Mexico. Results: 75% of papaya growers do not know about formal sources of credit that support their productive activity. Only 22.8% have used some type of financing, and only 2.6% came from formal credit sources, even though, 97.4% used semi-formal and informal financing options. 77.2 % of growers use their own economic resources for papaya production. This generates a great heterogeneity on production costs and crop management (level of technology) that reflects the final yield. Even under these conditions the crop is profitable. Limitations of the study/implications: Information from public or private credit institutions, does not reach potential users. The few farmers who have accessed a formal credit, have had bad experiences, such as embargoes and legal actions due to special situations that made them not paying on time, that discourage growers from using this type of credit. Findings/Conclusions: Lack of knowledge of the growers about financing sources. Low use of agricultural or other formal private credits, as 77.2% of growers used their own economic resources, which generates great heterogeneity in production costs associated with the level of technology, that is reflected in the crop yield, even so the papaya crop still is profitable

Escarificación química de semilla de papaya

Late germinating and erratic seed from papaya is affected by the presence of sarcotesta, membrane containing phenolic compounds inducing latency same which inhibits the exchange of liquids and gases, prolongs the drying period and facilitates colonization of pathogens. The techniques used in benefit of the papaya seed to eliminate the sarcotesta are limited, therefore the aim of this study was to obtain useful technology in this aspect, which was compared to other treatments with sodium hydroxide, sulfuric acid and hydrochloric acid and assessed its effect on the physical, health and physiological quality of the seed. The research was conducted at the Seed Testing Laboratory of the Graduate College, Campus Montecillo, State of Mexico, in 2011. NaOH to 25% and 15 min of immersion, removed 98% of sarcotesta, presented just 2% of incidence of micoflora, an increased and homogenized germination. H2SO4 to 100% removed the sarcotesta, inhibited fungal colonization with only 6% when used in concentrated form, but negatively affected the germination. The HCl was ineffective in eliminating sarcotesta (9.6%) had the highest fungal colonization (97% incidence) and the lowest germination percentage (7%). The positive effects of the use of NaOH in the benefit of papaya seed, is that simulates natural degradation of sarcotesta and improves the condition of the seed, so it is a viable alternative for use in conditioning seed.La germinación tardía y errática de semilla de papaya es afectada por la presencia de la sarcotesta, membrana que contiene compuestos fenólicos inductores de latencia, misma que inhibe el intercambio de líquidos y gases, prolongar el período de secado y facilitar la colonización de fitopatógenos. Las técnicas utilizadas en el beneficio de semilla de papaya para eliminar la sarcotesta son limitadas, por tanto, el objetivo del presente estudio fue obtener tecnología útil en éste aspecto, para lo cual se comparó tratamientos a base de hidróxido de sodio, ácido sulfúrico y clorhídrico, y evaluó su efecto en la calidad física, sanitaria y fisiológica de la semilla. La investigación se realizó en el Laboratorio de Análisis de Semillas del Colegio de Postgraduados, Campus Montecillo, Estado de México, en 2011. El NaOH al 25 % y 15 min de inmersión, eliminó 98% de sarcotesta, presentó sólo 2% de incidencia de micoflora, incremento y homogeneizó la germinación. El H2SO4 eliminó al 100% la sarcotesta, inhibió la colonización de hongos con sólo 6%, cuando se empleó en forma concentrada, pero afecto negativamente la germinación. El HCl fue ineficiente en eliminar la sarcotesta (9.6%), presentó la más alta colonización de hongos (97% de incidencia) y el menor porcentaje de germinación (7%). Los efectos positivos del uso de NaOH en el beneficio de semilla de papaya, simula la degradación natural de la sarcotesta y mejora la condición de la semilla por lo que resulta una alternativa viable para su empleo en el acondicionamiento de semilla

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved