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Photosynthetic response studies at different light intensities facilitate understanding plant physiology, optimizing management and sustainable use of species. The purpose of the research was to evaluate the photosynthetic response of G. angustifolia and B. vulgaris at different light intensities. Photosynthetic assimilation measurements were performed using a portable iFL - LCpro-SD system. The compensation point (┌ ⁕) was determined by three A/Ci curves under three different light intensity levels. The evaluation of the photosynthetic response to increasing light intensity was from 25 to 1800 PPFD μmol m-2s-1. G. angustifolia presented a ┌ ⁕ of 73.9 μmol CO2 m-2s-1, indicating higher carbon capture efficiency at lower concentrations compared to B. vulgaris, which showed a ┌ ⁕ of 88.1 μmol CO2 m-2s-1. Furthermore, G. angustifolia exhibited a lower diurnal respiration rate (Rd) (0.33 μmol CO2 m-2s-1, which optimizes its energy efficiency, while B. vulgaris presented a higher Rd (1.08 μmol CO2 m-2s-1, implying higher energy consumption under low light intensity conditions. G. angustifolia did not show photoinhibition, as its photosynthetic assimilation rate increased continuously with light. In contrast, B. vulgaris experienced photoinhibition starting at 700 μmol m-2s-1 of PPFD. These findings show that G. angustifolia is better adapted to capture carbon under conditions of low CO2, concentrations and high light intensities, while B. vulgaris seems to be better adapted to environments with higher CO2 concentrations. [ABSTRACT FROM AUTHOR]

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In this brief, non-exhaustive essay, we review major adaptive changes in reproductive and developmental traits of decapod crustaceans, which have passed through evolutionary transitions from ancestral life in coastal marine environments to brackish, limnic, polar, or deep-sea habitats. Two major approaches can be recognised in studies of life-history evolution, focussing on: (1) developmental changes in adaptive physiological or biochemical traits of successive ontogenetic stages, comparing, for instance, osmoregulatory capabilities in larvae, juveniles, and adults ("ontogeny of adaptations" perspective); (2) adaptive changes in the modes of reproduction and development, e.g., enhanced maternal energy investment in egg production, abbreviated, non-feeding larval development ("adaptations in ontogeny"). Using both scientific approaches, Christoph D. Schubart has significantly contributed to our understanding of evolutionary transitions in crustaceans. In our essay, we pay particular attention to the significance of nutritional selection factors in relation to presumably adaptive developmental, physiological, and biochemical traits in different life-history stages. In this context, we highlight the key roles of lipids and carotenoid pigments, in particular of essential polyunsaturated fatty acids (PUFAs) and astaxanthin. While PUFAs and other lipid compounds have received wide scientific attention, we propose that future studies should further analyse also the potential role of astaxanthin and other essential carotenoids. [ABSTRACT FROM AUTHOR]

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Los estudios de respuesta fotosintética a diversas intensidades lumínicas facilitan comprender la fisiología vegetal, optimizar el manejo y aprovechamiento sostenible de las especies. La investigación tuvo como fin evaluar la respuesta fotosintética de G. angustifolia y B. vulgaris a diferentes intensidades de luz. Las mediciones de asimilación fotosintética se realizaron utilizando un sistema portátil iFL - LCpro-SD. El punto compensación (% U ) se determinó mediante tres curvas A/Ci bajo tres niveles diferentes de intensidad lumínica. La evaluación de la respuesta fotosintética al incremento en la intensidad de luz fue de 25 a 1800 PPFD µmol m-2s-1. G. angustifolia presentó un % U de 73.9 µmol CO, m{ ²s{ ¹, indicando mayor eficiencia en la captura de carbono a concentraciones más bajas en comparación con B. vulgaris, que mostró un % U de 88.1 µmol CO, m{ ²s{ ¹. Además, G. angustifolia exhibió una menor tasa de respiración diurna (Rd) (0.33 µmol CO, m{ ²s{ ¹), lo que optimiza su eficiencia energética, mientras que B. vulgaris presentó una Rd más alta (1.08 µmol CO, m{ ²s{ ¹), lo que implica mayor consumo de energía en condiciones de baja intensidad lumínica. G. angustifolia no mostró fotoinhibición, ya que su tasa de asimilación fotosintética aumentó continuamente con la luz. En contraste, B. vulgaris experimentó fotoinhibición a partir de 700 µmol m{ ²s{ ¹ de PPFD. Estos hallazgos evidencian que G. angustifolia está mejor adaptada para capturar carbono en condiciones de baja concentraciones de CO, y altas intensidades de luz, mientras B. vulgaris parece adaptarse mejor a ambientes con mayor concentración CO.

Premise: Methods to evaluate lichen thalli hydrophobicity have previously been described, but only recently has hydrophobicity been shown to be an important functional trait related to water regulation dynamics that could be used to predict future climate change effects. We describe a novel protocol to measure lichen thallus hydrophobicity that aims to be an easier and more affordable approach. Methods and Results: Our protocol requires only a micropipette, distilled water, a tripod, and a smartphone or camera. Hydrophobicity is inferred from multiple metrics associated with the absorption times of standardized droplets (initial and total absorption time). We used a data set of 93 lichen taxa with different growth forms and from different biomes and demonstrated that this method is well suited for capturing different levels of hydrophobicity, including very hydrophilic species. Conclusions: Our results show that this new protocol to measure lichen hydrophobicity is a rapid and low‐cost method to assess an ecophysiologically based functional trait that can be used with almost no limitations, including in different climates, lichen species, and growth forms. [ABSTRACT FROM AUTHOR]

RESUMO Pressões ambientais cada vez mais se intensificam sobre a comercialização de madeiras de florestas tropicais no mundo. Alternativas que visem abastecer o mercado, frente a crescente demanda de madeira, urgem através de resultados de pesquisa e compromisso do setor público e empresarial. Com o objetivo de testar a plasticidade da espécie, o presente trabalho "Comportamento ecofisiológico do Mogno (Swietenia Macrophylla, King",) foi instalado no município de Miguel Pereira no estado do Rio de Janeiro, Brasil.

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Copyright of Revista Caatinga is the property of Revista Caatinga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

No processo evolutivo, após várias hibridações no “pool” genético inicial, ocorreram segregantes nos diferentes genótipos de pereira, que foram afetadas pelas diferenças edafoclimáticas, dando origem as diversas espécies. Atualmente, o gênero Pyrus compreende cerca de 25 espécies. Destas, cerca de 13 a 14 são originárias da China. As espécies de frutos pequenos, possivelmente, se originaram antes das de frutos grandes. É citada que a primeira espécie utilizada na alimentação humana foi a P. pyrifolia já que os seus frutos silvestres são comestíveis.

A EPAGRI 408-Condessa é produto de hibridação controlada efetuada em 1987 na Epagri/Estação Experimental de Caçador, SC, entre as cultivares Gala (mãe) e M-41 (pai) (Figura 1). A partir de uma população de 1.456 plântulas, em 1989 foram selecionadas 93 plântulas em termos de adaptação climática e fitossanidade. Estas 93 seleções preliminares foram enxertadas sobre o porta-enxerto anão M-9 para acelerar a frutificação e avaliar a qualidade dos frutos. Nos ciclos de 1991, 1992 e 1993 foram selecionadas 17 dentre as 93, as quais foram enxertadas sobre o porta-enxerto M-7 e avaliadas em nível de coleções em Caçador e em Fraiburgo, SC.

O objetivo deste estudo foi investigar a ação da luz e de tratamentos térmicos pré-germinativos na embebição de sementes de Alcantarea imperialis. As sementes foram dispostas em unidades experimentais de 25 sementes sem desinfestação prévia e submetidas a altas e baixas temperaturas e à ausência e presença de luz. Os resultados mostraram a germinação das sementes de A. imperialis somente na presença de luz, apresentando diferenças na absorção de água entre os tratamentos térmicos ao longo do tempo e confirmando o comportamento trifásico de embebição. Apesar das diferenças encontradas entre os tratamentos, a germinação foi baixa, sugerindo que o processo possa ter sido influenciado pela viabilidade das sementes e por processos hídricos puramente físicos. Nesse sentido, ressalta-se a importância de procedimentos de desinfestação e testes de vigor, bem como a necessidade de estudos futuros das relações hídricas das sementes dessa espécie.

This study aimed to clarify the kind of behavior before damage caused by various agents in their cotyledons. The research was conducted on the premises of the experimental area CCA, UFPI, in the period June- July 2019, with growing Italian Caserta. The experimental design was randomized blocks (DBC) with 4 repetitions and 11 treatments, treatments consisted to simulate different degrees of mechanical damage at different times after the emergence of the zucchini seedlings. Analysis of variance showed a significant difference only on the parameter dry weight of the stem. According to the results obtained from the analysis of dry matter, treatment affected only the stem, not influencing the leaves and roots, since the losses incurred in the removal of the cotyledons, regardless of the number or from the time that it was not affected height, root depth or number of leaves. Regarding the stem, perceive a trend of scathing effects with the removal of two cotyledons, especially in the early plant growth, at which time they are most required. [ABSTRACT FROM AUTHOR]

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La especie Beta vulgaris subsp. vulgaris comprende a las comúnmente llamadas remolachas, de las que existen tres tipos: hortícola, azucarera y forrajera. Aunque el principal órgano de interés es en todos los casos la raíz engrosada, las tres remolachas constituyen cultivos muy diferentes entre sí, tanto en cuanto a sus características agronómicas como a los productos que se obtienen de ellos, por lo que generalmente se han estudiado por separado. Sin embargo, la capacidad de esta especie de acumular en sus raíces altas concentraciones de compuestos bioactivos valiosos, junto con su probada adaptación a vastas áreas de clima templado han incentivado recientemente a escala global el interés por su cultivo, en concordancia con la creciente preocupación por la salud humana, la calidad de la alimentación y el cuidado del medioambiente. Este renovado interés plantea la necesidad de revisar el estado actual del conocimiento sobre la ecofisiología de los tres tipos de remolacha, de modo de contar con herramientas que permitan optimizar la productividad y la calidad de los productos obtenidos. En la presente revisión se realiza un análisis integrador de la información actualmente disponible sobre los distintos tipos de remolacha. Para ello, se reseñan las nuevas posibilidades de utilización, se analiza comparativamente la ecofisiología de los distintos tipos a lo largo del ciclo de cultivo, y se evalúan los aspectos críticos de la producción y calidad para cada uso. Muchos de los nuevos usos propuestos involucran a la remolacha hortícola, de la cual la información ecofisiológica disponible es relativamente escasa. Finalmente, se analiza en qué medida los conocimientos existentes acerca de un tipo de remolacha son extrapolables a los otros, y se discuten los estudios que podrán ser necesarios para en última instancia facilitar la difusión y adopción de los cultivos de remolacha con diferentes propósitos.

Antecedentes: La presencia de petróleo crudo (PC) en el suelo puede conllevar la muerte de especies vegetales que no logran aclimatarse a estas condiciones. Preguntas: ¿Cuál será la respuesta fisiológica de dos especies arbóreas creciendo en un suelo contaminado con diferentes concentraciones de PC? ¿Cuál será su plasticidad fisiológica en este contexto? Especies de estudio: Haematoxylum campechianum L. y Tabebuia rosea (Bertol.) DC. Sitio de estudio: Tabasco, México; 2017. Métodos: Se evaluaron variables fisiológicas en dos especies arbóreas establecidas en suelos contaminados bajo tres concentraciones de PC (15,170 a 15,600 mg kg-1) durante 292 días; se midió la asimilación de CO2 (A), transpiración (E), eficiencia en el uso del agua (EUA), eficiencia cuántica del fotosistema II (Fv/Fm y FPSII ), tasa de transporte de electrones (TTE), disipación no fotoquímica de energía (DNE), potencial hídrico, osmótico y contenido de clorofila. Resultados: Se encontró baja plasticidad fisiológica en ambas especies; hubo un efecto hormesis donde, en la concentración más baja de PC, los individuos presentaron un desempeño fisiológico superior comparado con plantas del tratamiento control. En T. rosea se registró un incremento en A, E, FPSII, DNE y Fv/Fm y una reducción en la TTE hacia el final del experimento en todos los tratamientos. H. campechianum presentó un incremento en la concentración de clorofila al final del mismo. Conclusiones: Tabebuia rosea presentó mayor variabilidad en sus respuestas fisiológicas comparada con H. campechianum, lo que sugiere que la primera podría ser más vulnerable a la presencia de petróleo crudo en suelo.

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La reducida cantidad de estudios que consideran los aspectos ecofisiológicos de las especies de plantas tropicales se debe en parte al costo elevado de la instrumentación. Sin embargo, la revolución tecnológica de la última década ha permitido desarrollar dispositivos electrónicos de bajo costo y que, aunado a los recursos de la inteligencia artificial, permiten obtener mediciones muy precisas. Todo lo anterior con el objetivo de promover una producción sostenible y de asegurar la conservación de ecosistemas. Este trabajo consiste en el desarrollo de un sistema electrónico capaz de adquirir datos espectrales a partir de imágenes del espectro visible de las hojas y procesar su reflectancia y longitud de onda, con la finalidad de analizar variables fisiológicas (tales como concentraciones de clorofila y nitrógeno) de las especies arbóreas tropicales en peligro de extinción.

Assim, foi desenvolvido este trabalho, com o objetivo de se buscar um melhor entendimento de como o fotoperíodo e a temperatura atuam sobre o cultivo da cebola, de forma a proporcionar aos agricultores catarinenses informações que lhe permitam obter a máxima produtividade e a melhor qualidade possíveis.

Diante da necessidade de se levarem aos produtores de sementes informações atualizadas sobre as regiões mais adequadas e sobre as melhores épocas para a produção, foi desenvolvido este trabalho de zoneamento agrícola para a produção de sementes de cebola em Santa Catarina.

The strawberry is a perennial plant of temperate climate belonging to the Rosaceae family, much appreciated for presenting a fleshy and succulent receptacle as an edible part. Among small fruits, in Brazil it represents the species of greatest economic expression. The breeding of the strawberry aims to meet the demands of the market, mainly regarding the quality of the fruit required by consumers. Thus, the selection of genotypes that have good quality, productivity and adaptation is extremely important for the development of culture in the country, as well as for making seedlings available at lower prices. The objective of this work was to evaluate the agronomic performance and productivity of experimental strawberry genotypes in the city of Alfenas, Minas Gerais. For this, the experiment was carried out in the premises of the José do Rosário Vellano University (UNIFENAS), Alfenas-MG, in an experimental area of the Olericulture and Experimentation Sector (21025'45"S, 45056'50 "W, 880 m altitude). The experimental design used was completely randomized, with eleven treatments, distributed in seven experimental genotypes, namely MDA01, MDA06, MCA 119, MFA444, MDA19, MDA11 and MDA23, and four commercial cultivars taken as control, being them Pircinque, Albion, Aromas and Festival, in eight repetitions. The following characteristics were evaluated total production per plant (grams of strawberries per plant-1), average weight of fruits per plant (grams/fruit-1), total number of fruits per plant and number of stolons (seedlings) per plant. The experimental genotypes that showed the highest total productivity and average fruit weight were MDA01, MDA23 and MDA19. These materials are presented as promising for the strawberry breeding program in the region and should be reevaluated under other edaphoclimatic conditions and/or used as parents in new crossings for the next stages of the program. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of exogenous application of salicylic acid on the photosynthetic metabolism and quality of Eugenia myrcianthes seedlings under water deficit and their recovery potential after rehydration. Two water regimes were evaluated, as follows: control - plants irrigated daily (I) and water deficit (S), with and without the application of 400 mg L-1 of salicylic acid (SA), totaling four treatments. Seedlings were evaluated at three times: at the beginning of the experiment (T0), that is, when the irrigation was interrupted; when the photosynthetic rate reached values close to zero (P0 - 15 days after irrigation interruption), that is, when irrigation restarted; and when the photosynthetic rate was recovered (REC). Eugenia myrcianthes seedlings were negatively affected when subjected to water restriction; salicylic acid attenuated the damage to the photosynthetic apparatus by acting positively on the relative water content in the leaves, SPAD index, photosynthetic metabolism, superoxide dismutase and peroxidase enzyme activity, and seedling growth in P0. Eugenia myrchiantes presented potential for recovery after resumption irrigation. The application of SA contributed to the maintenance of gas exchanges, photochemical processes and quality of E. myrcianthes seedlings during and after water deficit, suggesting the promotion of plant resistance induction. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the potential of shading in reducing the stressful effect of water restriction on photosynthetic and antioxidant metabolism, favoring the growth of Ormosia arborea seedlings and the recovery metabolic. The shadings levels studied were: 0, 30 and 70%. Two water regimes were implemented: control, in which the plants were irrigated at 75% of soil water retention capacity and water restriction, in which the irrigation was suspended until the photosynthetic rate reached values close to zero (P0), period at which the seedlings were re-irrigated. There were two evaluation periods: P0 and recovery. We observed that water restriction reduced photosynthetic metabolism, growth and quality of O. arborea seedlings by increasing the activity of antioxidant enzymes. The seedlings present higher quality index, stomatal conductance, intrinsic carboxylation efficiency and transpiration when cultivated under 70% shading in recovery. The stressful effect of water restriction was mitigated by the shading of 70%, where the seedlings were able to recover, resuming their photosynthetic metabolism and quality after resumption of irrigation. In addition, 0% shading is not indicated for this species. [ABSTRACT FROM AUTHOR]

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Introducción. Plantas expuestas a condiciones de estrés alteran su funcionamiento y generan respuestas fisiológicas que afectan su desempeño agronómico. En el cultivo de Cannabis medicinal, son escasos los trabajos de investigación sobre la fisiología de la planta y su interacción con factores bióticos. Objetivo. Determinar variables fisiológicas indicadoras de estrés en diferentes etapas fenológicas de plantas de Cannabis en invernadero y bajo condiciones fitosanitarias contrastantes. Materiales y métodos. El estudio se realizó entre noviembre y diciembre de 2019, en el Municipio Rionegro, Antioquia, Colombia. Semanalmente se sembraron lotes de plantas de Cannabis sativa L., provenientes de multiplicación asexual. Entre las semanas seis y doce posteriores al trasplante se evaluaron las variables índice y fluorescencia de clorofila (basal=Fo, máxima=Fm y variable=Fv), diferencial térmico cultivo ambiente, índice de estrés hídrico y concentración foliar de nutrientes desde el inicio de su fase vegetativa hasta la fase reproductiva y productiva, bajo dos condiciones fitosanitarias contrastantes una con la pudrición blanca causada por Sclerotinia sclerotiorum y la otra sin plagas ni patógenos. Resultados. Las plantas no presentaron estrés abiótico que afectara el aparato fotosintético en ninguna etapa. Los valores de cada nutriente estuvieron dentro de los rangos óptimos y los factores edáficos no representaron limitante para el desarrollo del cultivo. Se definieron valores referenciales de variables fisiológicas en distintos estados fenológicos bajo condiciones óptimas de desarrollo. En plantas enfermas con S. sclerotiorum, el índice de clorofila, el índice de estrés hídrico y la fluorescencia, mostraron valores referenciales que pueden ser útiles para la identificación de efectos perjudiciales en el fotosistema II. Conclusiones. En plantas enfermas el índice de clorofila y los parámetros Fv/Fm y Fv/Fo constituyeron variables indicadoras para detectar estrés biótico en plantas de Cannabis. En plantas sanas Fv/Fm, Fv/Fo, CWSI e índice de clorofila pueden evaluarse en experimentos sobre manejo agronómico del cultivo.

Paricá is part of the Caesalpinaceae family, a species native to the Amazon region. It is a species that has economic, environmental and social characteristics of great importance. The objective of this study was to evaluate the production of paricá seedlings in different types of substrate and shade levels in the eastern Amazon. The experiment was conducted at the seedling nursery of the Federal Rural University of the Amazon. In order to overcome dormancy, we used the mechanical scarification method with sanding on the part opposite the micropyle. The shading factor consisted of three levels, 50, 75 and 100%. The substrate factor consisted of four types P1, P2, P3 and P4. Analyzed variables were height, neck diameter and number of leaves. From the results it was observed that the environment had an effect on the interaction with height, diameter of neck and number of leaves (Test F = 5.40) and (CV = 14.3%). Between shading and substrate in relation to the height of the seedlings, it was expressive in the shading at 50%, presenting greater height in the substrate P1. Regarding the diameter of the neck, the 50% shade shade, presented 3.86 mm, P3 was the substrate that presented the highest average of 3.35 mm. The largest quantity of leaves, is in seedlings of the 50% and 75% shading, respectively. The seedlings from substrates P4 and P3, had the highest averages, 11.75 and 9.6 units. Paricá has good development in 50 and 75% shade, being considered the best environments for the production of healthy and quality seedlings. [ABSTRACT FROM AUTHOR]

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La feijoa es un frutal con gran potencial para el consumo humano, que se cultiva entre los 1800 y 2700 msnm en Colombia. Está bien adaptada a temperaturas bajas, resistiendo por corto tiempo temperaturas 32 °C afectan su floración. La temperatura base para botón floral a antesis es 2,89 °C, de antesis a cuajamiento del fruto es de 3,04 °C y del cuajamiento del fruto a cosecha, 1,76 °C. El árbol crece muy bien en suelos aluviales, profundos y ricos en materia orgánica. En la poda del árbol es importante la formación en cono con tres niveles de ramas agobiadas y la eliminación de los chupones, para fomentar así la floración y la longevidad del árbol. En los pocos estudios fisiológicos se encontró una tasa fotosintética baja (en promedio entre 4 y 6 μmol CO2 m-2 s-1), con gran demanda energética durante la floración, mientras la transpiración aumenta con la irradiancia, la temperatura y la disminución de la humedad relativa, mostrando un mayor número de estomas foliares en el estrato superior de la copa (91/mm2), comparado con el inferior (78/mm2). El inicio de la etapa reproductiva está favorecida por las condiciones más secas y por la fertilización con KH2PO4 al 0.5 %. En Colombia, frutos de mayor calibre y producciones más altas se logran a través de la polinización por la mirla negra (Turdus fuscater). El fruto necesita entre 120 y 150 días para desarrollarse y se presentan producciones entre 30 y 40 kg/árbol (≥20 t ha-1). El color verde del fruto en todos sus estados dificulta la determinación del grado de madurez.

Estudos com espécies florestais, em diferentes condições ambientais são essenciais para o entendimento da relação planta-ambiente. Diferentes condições de luminosidade podem interferir na produção de mudas florestais e o reflexo dessa interferência pode ser verificado pela análise da área foliar. No entanto, muitas espécies apresentam folhas compostas, sendo muitas vezes com inúmeros folíolos, o que dificulta as análises com mensuração direta da área foliar, proporcionando dúvidas durante a análise, se devem ser separados para análise ou mensurados com a folha inteira. Assim, o objetivo desse estudo foi analisar a área foliar específica em folhas inteiras e folíolos destacados de folhas compostas de seis espécies florestais submetidas à diferentes níveis de sombreamento. As espécies florestais utilizadas foram Schinus terebinthifolius Raddi (aroeira), Schinopsis brasiliensis Engl. (braúna), Dalbergia nigra (Vell.) Fr. All. ex Benth. (jacarandá-da-bahia), Chorisia speciosa A.St.-Hil (paineira), Caesalpinia peltophoroides Benth (sibipiruna) e Plathymenia reticulata Benth (vinhático), todas com folhas compostas. Cada espécie foi submetida a seis tratamentos de sombreamento: 0% (pleno sol); 20; 40; 60; 80 e 90%, com a utilização de “sombrites” para os tratamentos sombreados. A análise da área foliar específica foi realizada de duas maneiras: folíolos separados e folha inteira. Para a análise dos folíolos esses foram obtidos de três medidas (repetições) de 50 folíolos por planta, realizada em seis plantas por tratamento. Para a análise da folha inteira os dados foram obtidos de folhas inteiras de seis plantas por tratamento. Esse processo se repetiu em todas as espécies supramencionadas. Para todas as espécies, os dados indicaram um padrão de resposta semelhante em ambos os métodos de análise, variando de acordo com os níveis de sombreamento. Essa similaridade dos dados demonstra que, para essas espécies, não é necessário a utilização de métodos muito complexos para a obtenção da área foliar específica. Assim, a obtenção da área foliar específica utilizando a folha inteira fornece resultados estatisticamente iguais em relação àquela obtida utilizando somente folíolos.

La restauración de bosques de Austrocedrus chilensis requiere plantines que soporten difíciles condiciones postrasplante. Durante la etapa de propagación en vivero, es común emplear cubiertas plásticas y mallas media sombra para la producción de plantines, pero esto induce una aclimatación a la intensidad lumínica que puede afectar su comportamiento al trasplante. El objetivo de este trabajo consistió en estudiar las características morfológicas y fisiológicas de la aclimatación y sus consecuencias sobre la mortalidad y crecimiento postrasplante a campo. Para esto se establecieron dos ensayos. En el primero se evaluaron los cambios de asignación de biomasa de hojas, tallos, raíces, y las variaciones de algunos parámetros fotosintéticos de 90 plantines aclimatados a tres niveles de luz durante tres años. En el segundo ensayo se trasplantaron 360 plantines en un diseño bifactorial (cobertura del micrositio y aclimatación en vivero) con dos niveles cada factor. Con los datos de este experimento se ajustaron un conjunto de modelos lineales de efectos mixtos, (Ho nulas y alternativas), y se estimaron las tasas de mortalidad y de crecimiento como respuesta a los factores; los modelos fueron contrastados entre sí mediante una prueba de cociente de verosimilitud (LRT). La aclimatación en vivero produjo cambios de área foliar específica (P

Copyright of Innotec is the property of Laboratorio Tecnologico del Uruguay and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ciência Agronômica is the property of Revista Ciencia Agronomica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A manifestação do potencial produtivo das culturas depende de fatores genéticos e de condições favoráveis de ambiente e de manejo. Objetivou-se determinar os efeitos das épocas de semeadura na eficiência do uso da radiação solar, nos índices morfofisiológicos e na produtividade de grãos de cultivares contrastantes de arroz de terras altas. O experimento de campo foi conduzido na região central do Brasil em solo sob Cerrado. O delineamento experimental foi em blocos ao acaso no esquema fatorial 3 x 5, com oito repetições. Os tratamentos foram compostos pela combinação de três cultivares (BRS Primavera, BRSMG Curinga e Douradão) com cinco datas de semeadura (11/09/2012, 22/10/2012, 28/11/2012, 21/12/2012 e 27/2/2013). Todas as cultivares requereram menos graus-dia acumulados para atingir a fase reprodutiva quanto mais tardia foi a data de semeadura. Os menores acúmulos de biomassa e índices de área foliar das três cultivares ocorreram na data de semeadura mais precoce, o que pode ter sido resultado de menor eficiência do uso da radiação (EUR) nesse período. A partição de assimilados para as folhas e colmos foi semelhante entre as cultivares, contudo a taxa de assimilação/translocação de carboidratos para as panículas foi maior para as cultivares BRSMG Curinga e Douradão. As cultivares diferiram quanto ao número total de grãos por área, tendo a cultivar Douradão apresentado o maior número e a BRS Primavera o menor. As maiores produtividades foram obtidas nas datas de semeadura que abrangeram o período tradicional de semeadura do arroz de terras altas, outubro a dezembro.

O conhecimento das tolerâncias e exigências das espécies a diferentes disponibilidades de luz ajuda a entender a estruturação de comunidades e a regeneração de áreas degradadas. O objetivo do trabalho foi avaliar o crescimento inicial de mudas de Acnistus arborescens em um gradiente de luz. O experimento foi conduzido no Núcleo de Ensino e Pesquisa em Agricultura Urbana, da Universidade Federal do Ceará. Para obtenção das mudas foi realizado a semeadura em bandejas e 30 dias depois as plântulas foram repicadas para sacos de polietileno de 12x25 cm contendo solo e húmus. Os tratamentos foram constituídos de quatro níveis de sombreamento: sol pleno (0% de sombreamento), 50, 70 e 90% de sombreamento, e cinco períodos de avaliação (30, 51, 72, 93 e 114 dias após a repicagem) combinados num arranjo de parcelas subdivididas no delineamento em blocos ao caso com quatro repetições (5 plantas/repetição/período). As variáveis analisadas foram altura, diâmetro, comprimento da raiz, peso da matéria seca das folhas, caule e raiz, área foliar e relação raiz/ parte aérea. A maior altura e produção de biomassa foi observado nas plantas que estavam em ambiente sombreado. Os resultados obtidos mostraram que Acnistus arborescens apresenta um melhor desenvolvimento inicial em ambiente sombreado, e que embora a espécie seja descrita como heliófita, a condição de sol pleno estudada afetou negativamente o desempenho desta espécie.

Un estudio fue llevado a cabo en el Parque Natural Metropolitano con el propósito de determinar el movimiento de dispersión de la mosca del gusano barrenador, Cochliomyia hominivorax, dentro el bosque. Asimismo, se determinó entre septiembre de 1996 a abril de 1997 la distribución poblacional, la actividad diaria y el efecto de los parámetros físicos sobre estas moscas. Para esto se colocaron tres sitios de colecta, dos dentro y uno en el borde del bosque, empleando hígado de res como atrayente. La temperatura y la velocidad del viento fueron medidas en el momento de la captura de cada mosca. Un total de 305 moscas fueron capturadas en 74 días de colecta con un promedio de 3.1  5.33 moscas por día. Durante la estación seca se colectó significativamente mayor cantidad de moscas que en la temporada lluviosa. La temperatura media y velocidad del viento promedio en la cual se capturaron estas moscas fueron de 29.7  2.2ºC y 0.47  1.51 Km/h, respectivamente. La temperatura media de captura se correlacionó positivamente y la precipitación negativamente con el número de moscas capturadas. El puesto 2 fue donde se capturó significativamente mayor cantidad de moscas. Estas moscas presentaron mayor actividad durante las horas de la mañana entre las 10:00 y 11:00 a.m., con otro pico más pequeño entre las 3:00 y 4:00 p.m. De las 305 moscas colectadas, 27 fueron recapturadas, siendo el puesto 2 el que presentó un número significativamente mayor de moscas. Además, este fue el sitio que contribuyó con mayor número de moscas hacia los demás puestos. Nuestros resultados indican una baja población de esta especie en el Parque Natural Metropolitano (PNM), con una baja tasa de recaptura. Esto probablemente, está relacionado con el movimiento de los mamíferos silvestres en el área y las características peculiares de este hábitat.

The present review compiles the studies carried out so far on Opuntia ellisiana Griffiths. This species, of unknown origin, was first described at the beginning of the 20th century in southern Texas, USA, and introduced to Argentina in 1998. This species, like other Opuntia sps., can be cultivated in a wide range of environments and its lower transpiration per unit of carbon gained in relation to C3 and C4, has lead to in an important increase in water-use efficiency. While O. ellisiana has a lower growth and productivity than O. ficus-indica (L.) Mill. it stands out for its resistance to sub-zero temperatures. Fortunately, the intraspecies variation within O. ellisiana, shortens the time for its use after establishment. There is a wide variation in the nutrient content between the different forage species and clones of Opuntia. Due to the inherently low N availability in arid ecosystems, O. ellisiana, like the other species, has low protein content in natural unfertilized conditions. Some efforts, as the use of N-fertilizer, have been carried out to improve its protein level. About 15% protein levels have been obtained with other Opuntias. Other research has been directed to provide a favorable abiotic environment for a cactus to achieve higher biomass productivity and improved protein levels by interacting with nurse plants, such as Prosopis sps. The last alternative resulted in a significant increase in protein content and cladode quantity per plant of O. ellisiana. [ABSTRACT FROM AUTHOR]

Araucaria angustifolia is an ecologically and commercially important species of the Atlantic Forest. However, its ability to regenerate continuously under the shade of the canopy in the rainforest is uncertain. The aims were: to evaluate the morpho-physiological responses of araucaria to different intensities of canopy coverage to know its shade acclimation capacity; and to evaluate survival and growth under different shade intensities in gaps. First, seedlings were grown in pots at full sun or under canopy shade and morphophysiological traits were measured after 6 and 12 months. Survival was 100% under full sun and 40% under shade. One year after planting, the ability to use high-intensity light was similar in plants under both conditions, although shade plants did not grow and showed little capacity to acclimate to shade. Plants under full sun duplicated their size in six months and had higher capacity to deliver water to the leaves. However, shade plants had higher specific hydraulic conductance. After that, in a field experiment, seedlings were planted in six forest-gaps to record survival and growth for 30 months. Survival was high in all positions within the gaps. In the center of the gaps, where incident radiation was higher, growth was higher. We conclude that araucaria has low ability to acclimate to low radiation, nevertheless, it can survive at least 30 months under the canopy. Consequently, araucaria should not be planted below dense canopy shade. The microenvironment in the center of 195-293 m2 gaps is proper for araucaria growth. [ABSTRACT FROM AUTHOR]

Copyright of BIOAGRO is the property of Revista BIOAGRO and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cladocerans are microcrustaceans component of the zooplankton in a wide array of aquatic ecosystems. These organisms, in particular the genus Daphnia, have been widely used model organisms in studies ranging from biomedical sciences to ecology. Here, we present an overview of the contribution of studies with cladocerans to understanding the consequences at different levels of biological organization of stress induced by environmental factors. We discuss how some characteristics of cladocerans (e.g., small body size, short life cycles, cyclic parthenogenesis) make them convenient models for such studies, with a particular comparison with other major zooplanktonic taxa. Then we illustrate the contribution of cladocerans to stress research with examples encompassing stress responses spanning from the molecular to the populational level. Most worth of note are recent studies that presented evidence of beneficial consequences of mild stress caused by natural stressors (cross-tolerance), which may be passed along across generations, favoring individual survival and species persistence in fluctuating environments. This would be particularly relevant for environments prone to frequent natural environmental fluctuations, such as coastal lagoons and other shallow aquatic ecosystems. Based on reviewed studies, a conceptual model is presented summarizing the potential effects of a first stressor on the organism's resistance to a second one. We finish by highlighting some gaps on environmental stress research that could benefit from further studies using cladocerans as model organisms.

'Valencia' sweet orange is widely cultivated in Colombian tropical lowlands, with low yields and a lack of technology. As a result, nine rootstocks commonly used in tropical zones: 'C-35', 'Carrizo', 'Swingle' citrumelo or CPB 4475, 'Cleopatra', 'Sunki × English', 'Volkamer', 'Webberi' and 'Yuma' were evaluated. The plants were established in 2001 and were evaluated for vegetative growth, fruit yield and quality for 10 years (2004-2013). The obtained results indicated that 'Sunki × English' and 'Volkamer' were the best rootstocks for fruit yield and the worst was 'Yuma'. Furthermore, all of the rootstocks, except 'Yuma', stabilized their height in the last year. In terms of volume, 'Amblycarpa' and 'Cleopatra' were the bigger plants and 'Yuma' was the smallest. In addition, for yield efficiency, 'Yuma' had the best rootstocks, followed by 'Sunki × English'. All of the rootstocks showed a similar fruit quality, except for 'Sunki × English', which obtained the highest total soluble solids/total titratable acids ratio.

The selection of new genotypes of forage spineless cacti is essential, mainly due to the limited number of existing materials, for this the evaluation of the physiological aspects can be an important criterion to consider. In this context, an experiment was carried out from January to November 2016 at the Benjamim Maranhão Experimental Station, belonging to EMEPA-PB in the municipality of Tacima, state of Paraíba, Brazil, objectifying to evaluate the quantum yield and water use efficiency of forage spineless cacti genotypes in the Brazilian Semiarid. The experiment was conducted in a randomized block with 6 treatments, corresponding to the genotypes V07 Negro Michoacan, V14 California, T03 Raio Vigor, T42 Amarilla Vach, FR Direkteur e F16 Oreja de Elefante, all of Mexican origin, originating from the EMEPA germplasm bank in three replicates, with 20 plants per experimental unit. The evaluated variables were chlorophyll a fluorescence initial, maximum and variable, in addition to the variable/initial fluorescence ratio, potential quantum income, efficiency of rainfall use, water accumulation and cultural hydric footprint. The genotypes V07 and V14 were more efficient (P <0.05) in the photochemical activity of photosystem II, potentializing its photochemical activity, expressing also greater efficiency in water use, being recommended for cultivation in the semiarid region. [ABSTRACT FROM AUTHOR]

A limiting factor for wheat crop expansion or off-season crop in the Brazilian Cerrado is the occurrence of elevated temperatures during cropping cycle. This study aimed to evaluate the effects of temperature during the spikelet differentiation stage on biometric and productive parameters of wheat cultivars. A greenhouse experiment was carried out under a randomized blocks design, organized in a 2 x 4 factorial scheme, with four replicates. Two day/night thermo periods (16/9 ˚C and 25/16 ˚C) were applied in four wheat cultivars (BRS 394, BRS 331, BRS Parrudo and BRS Guamirim) during the spikelet differentiation stage. Yield components were determined for individual tillers and for the whole plant. Both thermo periods do not affect yield components of wheat, either morphological and productive uniformity of tillers, which show large variation among wheat cultivars. [ABSTRACT FROM AUTHOR]

Copyright of Engenharia na Agricultura is the property of Engenharia na Agricultura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the southern area of the state of Jalisco, Mexico, cultivation of 'Méndez' avocado (Persea americana Miller) is important due to its adaptation to the semi-warm climate of the region and because of its early maturation and harvest (summer), in relation to 'Hass' (fall), although the lack of knowledge of its phenology makes the effective management of 'Méndez' orchards difficult. The objective of this study was to document the phenology of 'Méndez' during two production cycles (2014-15 and 2015-16), in two commercial orchards with supplementary irrigation from October to June (annual rain of 728 mm), established in soils of volcanic origin and light texture in southern Jalisco. The maximum temperatures of the soil at 30 cm from the surface were in May (24.5 °C) and the minimum from January to March (15.9 to 14.5 °C). The vegetative flushes (VF) were found in summer (August-September) and winter (February), as well as flowering in summer (September) and winter (February). Flower development (vegetative bud to anthesis) in shoots from the summer and winter VFs lasted 187 and 222 d, respectively. The fruit drop (5 to 6 cm of diameter) was similar in the two flowering seasons (55.4 to 61.8 %). The fruit maturity (≥22.7% d.m.) happened in July and in September-October for fruits from the summer and winter flowering periods, respectively. There were two flushes of root production and the greatest was in summer (June to August). The maximum and minimum average environmental temperatures of the warmest (April to June) and coldest (January to March) months were 31 and 9 °C, respectively. The results from this study are basic to compare the future changes in the phenology of 'Méndez' avocado. [ABSTRACT FROM AUTHOR]

The study was performed in the greenhouse of the Federal University of Grande Dourados (UFGD), from April to May, 2015. The aim of this study was to assess the effect of abscisic acid (ABA) different concentrations on Hymenaea courbaril L. seedlings water stress response and recovery after the rehydration. The following six treatments were evaluated: 1) Irrigation 0 μM ABA; 2) Irrigation + 10 μM ABA; 3) Irrigation + 100 μM ABA; 4) Irrigation without 0 μM ABA; 5) Irrigation without + 10 μM ABA and 6) Irrigation without + 100 μM ABA. The irrigation without treatment was performed by withouting water until the photosynthetic rate was close to zero, after which the plants were rehydrated. The plants were then irrigated daily to maintain 70% of the water holding capacity of the soil for a 12-day recovery period. The ABA doses applied exogenously during the irrigation without period neither prevented the reduction of photosynthetic activity nor optimized the recovery of the gas exchanges and the carboxylation efficiency of Rubisco after water and seedling quality restoration. The 100 μM ABA concentration promoted the degradation of chlorophylls independent of irrigation, showing that high concentrations of ABA may cause a residual effect on this species. The seedlings exhibited normal metabolic recovery after about 12 days of re-irrigation of the soil, which we attribute to species characteristics and not the tested treatments. [ABSTRACT FROM AUTHOR]