Tasa relativa de crecimiento en plántulas de dos poblaciones de Magnolia pugana (Magnoliaceae) en distintos niveles de luz y fertilidad del suelo / Relative growth rate in Magnolia pugana (Magnoliaceae) seedlings from two populations at different light levels and soil fertility

Resumen El estudio de la ecofisiología de las especies en peligro de extinción es clave para el éxito de programas de conservación y restauración ecológica. El objetivo de este trabajo fue conocer el efecto de los factores luz, fertilidad de suelo y procedencia de las plántulas en el crecimiento de plántulas de Magnolia pugana. Se estimó la tasa relativa de crecimiento (TRC) y sus componentes (Tasa de Asimilación Neta: TAN y Cociente del Área Foliar: CAF), así como la relación raíz/vástago (C: R/V). Las plántulas fueron obtenidas de semillas recolectadas de dos localidades en Zapopan, Jalisco, México, la primera es una población silvestre en San Nicolás (SN) y la segunda es una plantación ubicada en los jardines del Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA). El experimento se llevó a cabo en condiciones de invernadero. En septiembre 2015, 96 plántulas de tres meses de edad fueron sometidas a los siguientes tratamientos con un experimento factorial (2 × 2 × 2): nivel de luz (alta = 1 120 μmol m-2 s-1 y baja = 136.3 μmol m-2 s-1), procedencia de las plántulas (San Nicolás y CUCBA) y fertilidad del suelo (alta = suelo San Nicolás, baja = suelo del CUCBA) con 12 repeticiones por cada combinación de factores y niveles. El crecimiento se estimó con dos cosechas: la primera a los 30 días de establecido el experimento y la segunda a los 60 días. Los niveles de luz, fertilidad del suelo y la procedencia de las plántulas influyeron en el crecimiento a través de ajustes fisiológicos y morfológicos. En general Magnolia pugana mostró mayor TRC y TAN en la luz alta, mientras que el CAF disminuyó. La fertilidad del suelo y la procedencia de las plántulas no afectaron la TRC ni sus componentes. Sin embargo, si fueron afectados por los niveles de luz, las plántulas de SN crecieron más en luz alta. La altura del tallo varió debido a la fertilidad del suelo y a la procedencia de las plántulas, en el suelo con fertilidad baja, en el suelo del CUCBA las plántulas de SN fueron 35 % más altas que las del CUCBA. El suelo de baja fertilidad en la luz alta ocasionó que las plántulas asignaran mayor biomasa a la raíz. El componente fisiológico (TAN) fue el mayor determinante en la variación intraespecífica de la TRC. Las plántulas de SN mostraron mayor plasticidad fenotípica debido a que es una población silvestre, por lo que posiblemente tiene variación genética más alta que la población cultivada del CUCBA. Los resultados sugieren que Magnolia pugana es una especie con capacidad de adaptarse a diversos ambientes debido a su plasticidad fenotípica frente a los distintos niveles de luz y fertilidad del suelo.

Abstract The study of ecophysiology of endangered species is key to the success of conservation and ecological restoration programs. The objective of this work was to know the effect of light, soil fertility and seed origin on the growth of Magnolia pugana seedlings. The relative growth rate (RGR) and its components (Net Assimilation Rate: NAR and Leaf Area Ratio: LAR), as well as the root-shoot ratio (R/S) were estimated. Seedlings were obtained from seeds collected in two localities in Zapopan, Jalisco, Mexico, the first is a wild population in San Nicolás (SN) and the second is a plantation located in the gardens of the Centro Universitario de Ciencias Biológicas y Agropecuarias (CUCBA). The experiment was conducted under greenhouse conditions. In September 2015, 96 seedlings of approximately three months old were subjected to the following treatments in a factorial experiment (2x2x2): light level (high = 1 120 μmol m-2 s-1 and low = 136.3 μmol m-2 s-1), seedling origin (SN and CUCBA) and soil fertility (high fertility = SN soil, low fertility = CUCBA soil) with 12 replicates for each combination of factors and levels. Growth was estimated in two harvests: the first harvest after 30 days of starting the experiment and the second at 60 days. Light and soil fertility levels, as well as seedling origin influenced growth through physiological and morphological adjustments. In general, Magnolia pugana showed higher RGR and NAR in high light, while LAR decreased. Soil fertility and seedling origin did not affect RGR or its components. However, these were affected by the light level, seedlings from SN grew more in high light. Stem height varied due to soil fertility and seedling origin, in low fertility soil (CUCBA) the seedlings of SN were 35 % higher than those of CUCBA. Low fertility soil under high light caused greater investment in seedling root biomass. The physiological component (NAR) was the major determinant of intraspecific variation in RGR. SN seedlings showed greater phenotypic plasticity due to coming from a wild population, which possibly has higher genetic variation than the cultivated population from CUCBA. The results suggest that Magnolia pugana is a species capable of adapting to diverse environments due to its phenotypic plasticity in response to different light and soil fertility levels. Rev. Biol. Trop. 66(2): 622-633. Epub 2018 June 01.

Aplicación del índice de calidad de suelos en plantaciones forestales de palo blanco (Tabebuia donnell-smithii Rose) y Matilisguate (Tabebuia rosea Bertol) en Guatemala / Application of the soil quality index in forest plantations of palo blanco (Tabebuia donnell-smithii Rose) y Matilisguate (Tabebuia rosea Bertol) in Guatemala

El desarrollo forestal y el manejo sostenible de los ecosistemas forestales se fundamentan en la forestación,propiciada por la Ley de Fomento al Establecimiento, Recuperación, Restauración, Producción y Protección deBosques en Guatemala, Probosques. Por lo que reviste importancia el conocimiento de las características edáficas de sitio que garanticen el establecimiento y desarrollo de las plantaciones forestales. Esta investigación presentauna aplicación del índice de calidad de suelos forestales (SQI) desarrollado por el Departamento de Agricultura yServicio Forestal de los Estados Unidos de América, para calificar sitios forestales con base en propiedades fisicoquímicas de los suelos. Se evaluaron 22 sitios forestales ubicados tanto en la parte norte como sur del país, con plantaciones jóvenes de palo blanco (Tabebuia donnell-smithii Rose) y matilisguate (Tabebuia rosea Bertol). Los sitios fueron categorizados en clase I (SQI = 90%); clase II (SQI = 75%); clase III (SQI = 70%); clase IV (SQI =65%) y clase V (SQI = 55%), lo anterior con objeto de describir condiciones edáficas de sitio, que contribuyan al éxito del establecimiento de plantaciones forestales en el país. Se concluye que el SQI es una herramienta práctica que permitió agrupar sitios en términos edafológicos, lo que puede utilizarse con múltiples fines para optimizar la productividad de las tierras forestales en el país.

Forestry development and sustainable management of forest ecosystems are based on forestry, organized bythe Law for the Promotion of Establishment, Recovery, Restoration, Production and Protection of Forests inGuatemala, called Probosques. Therefore, it is important to generate knowledge of edaphic site features, that ensure the establishment and growth of forest plantations. This research presents an application of the Soil Forest Quality Index (SQI) developed by the Department of Agriculture and Forest Service of the United States of America, to qualify forest sites based on physico-chemical soil properties. Twenty-two forest sites located on both the northand south of the country, with young plantations of white wood (Tabebuia donnell-smithii Rose) and Matilisguate(Tabebuia rosea Bertol) were evaluated. The sites were categorized into Class I (SQI = 90%); Class II (SQI = 75%);Class III (SQI = 70%); Class IV (SQI = 65%) and Class V (SQI = 55%), the above in order to describe edaphic siteconditions that contribute to the successful establishment of forest plantations in the country. It is concluded that the SQI is a practical tool that allowed group sites in pedological terms, which can be used for multiple purposesto optimize productivity of forest land in the country.

What are the most important factors determining different vegetation types in the Chapada Diamantina, Brazil? / Quais são os fatores mais importantes na determinação de diferentes tipos de vegetação na Chapada Diamantina, Brasil?

Abstract A transect was used to examine the environmental and biological descriptors of a compact vegetation mosaic in the Chapada Diamantina in northeastern Brazil, including the floristic composition, spectrum of plant life forms, rainfall, and soil properties that defined areas of cerrado (Brazilian savanna), caatinga (seasonally dry tropical forest thorny, deciduous shrub/arboreal vegetation) and cerrado-caatinga transition vegetation. The floristic survey was made monthly from April/2009 to March/2012. A dendrogram of similarity was generated using the Jaccard Index based on a matrix of the species that occurred in at least two of the vegetation types examined. The proportions of life forms in each vegetation type were compared using the chi-square test. Composite soil samples were analyzed by simple variance (ANOVA) to examine relationships between soil parameters of each vegetation type and the transition area. The monthly precipitation levels in each vegetation type were measured and compared using the chi-square test. A total of 323 species of angiosperms were collected distributed in 193 genera and 54 families. The dendrogram demonstrated strong difference between the floristic compositions of the cerrado and caatinga, sharing 2% similarity. The chi-square test did not demonstrate any significant statistical differences between the monthly values of recorded rainfall. The organic matter and clay contents of the soilsin the caatinga increased while sand decreased, and the proportions of therophyte, hemicryptophyte, and chamaephyte life forms decreased and phanerophytes increased. We can therefore conclude that the floristic composition and the spectrum of life forms combined to define the cerrado and caatinga vegetation along the transect examined, with soil being the principal conditioning factor determining the different vegetation types, independent of precipitation levels.

Resumo Foi estabelecida uma transecção para examinar descritores ambientais e biológicos em uma área compacta de vegetação em mosaico na Chapada Diamantina, Nordeste do Brasil. A composição florística, espectro de formas de vida, precipitação e propriedades do solo foram avaliadas na transecção entre cerrado (savana brasileira) e caatinga (floresta tropical sazonalmente seca espinhosa, vegetação arbustivo-arbórea decídua), separados por vegetação de transição cerrado-caatinga. O levantamento florístico foi realizado mensalmente de abril de 2009 a março de 2012. Foi feita análise de agrupamento a fim de determinar a similaridade entre as fisionomias de cerrado, a caatinga e a transição cerrado-caatinga. As proporções de formas de vida foram comparadas utilizando o teste qui-quadrado. Amostras compostas de solo foram analisadas por variância simples (ANOVA) testando a existência de diferenças entre os solos de cada tipo de vegetação. A precipitação mensal em cada tipo de vegetação foi mensurada e os resultados comparados com o teste qui-quadrado. Coletamos 323 espécies de angiospermas pertencentes a 193 gêneros e 54 famílias. A análise de agrupamento demostrou diferença entre a composição florística do cerrado e da caatinga, com apenas 2% de similaridade. O teste qui-quadrado não demonstrou diferença estatística entre os valores registrados para cada mês. À medida que os conteúdos de matéria orgânica e argila aumentaram e o de areia diminuiu na caatinga, a proporção das formas de vida terófito, hemicriptófito e caméfito diminuiu e a de fanerófitos aumentou. Podemos considerar que a composição florística e o espectro de formas de vida delimitaram o cerrado e a caatinga na transecção estudada e que o solo foi o principal fator condicionante para determinação dos diferentes tipos de vegetação, independentemente da precipitação.

Atividade antagonista do óleo essencial de Lippia alba (Mill. ) N. E. Brown (Verbenaceae) sobre Meloidogyne incognita (Kofoid & White) Chitwood / Antagonist activity of the essential oil Lippia alba (Mill. ) N. E. Brown (Verbenaceae) on Meloidogyne incognita (Kofoid & White) Chitwood

RESUMO O controle de fitonematóides é uma tarefa difícil. A alta infestação de nematoides no solo obriga os produtores a usarem doses mais elevadas de nematicidas, ou ainda, a aumentarem a freqüência das aplicações, geralmente no solo, ocasionando maior potencial de dano ao homem e ao ambiente. Além disso, nematicidas convencionais vêm sofrendo grandes restrições de uso em muitos países. Desse modo, a busca de novas medidas de controle de fitonematóides é uma prioridade da agricultura sustentável. Desta forma, objetivou-se estudar o efeito de óleos essenciais de Lippia Alba, na mortalidade de juvenis pré-parasitas do segundo estádio de Meloidogyne incognita. O ensaio foi montado em delineamento inteiramente casualizado, com 4 repetições, em esquema fatorial 3×4 (3 quimiotipos x 4 concentrações) empregando-se três diferentes quimiotipos de L. Alba (I, II, III) nas concentrações de 0, 100, 500 e 1000 ppm, coletados em diferentes horas do dia (7, 9, 13, 16 e 19h). Os dados coletados (% de mortalidade) foram submetidos à análise de variância e os valores médios comparados por meio do teste de Tukey. Foi possível concluir que Lippia alba contém, em seu óleo essencial, compostos com efeitos significativos na mortalidade de juvenis de segundo estádio (J2) de M. incognita. Dessa forma, é importante destacar que o acentuado efeito nematicida do óleo essencial de L. alba sugere a possibilidade de seu uso no controle de M. incognita.

ABSTRACT The control of nematodes is difficult. The high infestation of nematodes in the soil requires the producers use higher doses of nematicides, increasing the frequency of applications, usually in soil, causing negative effects to humans and the environment. Furthermore, conventional nematicides have suffered great use restrictions in many countries. Thus, the search for new measures to control nematodes is a priority of sustainable agriculture. Thus, the objective of this study was available the effect of essential oils from Lippia Alba against Meloidogyne incognita. The experiment was conducted in a completely randomized design with four replications in a factorial 3x4 (3 chemotypes and 4 concentrations) using three different chemotypes of L. Alba (I, II, III) at concentrations of 0, 100, 500 and 1000 ppm, collected in different times of day (7 AM, 9 AM, 1 PM, 4 PM e 7 PM). The data collected (% mortality) were subjected to analysis of variance and mean values were compared using the Tukey test. It was able to conclude that L. alba contains in its essential oil, compounds with significant effects on mortality of M. incognita. Thus, it is important to note that the greatest nematicide effect of essential oil of L. alba suggests the possibility of its use to control M. incognita.

Rendimento do coentro (Coriandrum sativum L) adubado com esterco bovino em diferentes doses e tempos de incorporação no solo / Yield of the coriander [Coriandrum sativum (L)] fertilized with manure at different doses and incorporation times in the soil

RESUMO O uso de esterco bovino é de suma importância para os agricultores familiares que produzem coentro na região de Mossoró-RN, pois esse insumo é amplamente disponível e utilizado pelos agricultores. Objetivando-se avaliar o Rendimento do coentro fertilizado com esterco bovino em diferentes doses e tempos de incorporação ao solo foi conduzido um experimento no período de setembro a novembro de 2011, na Fazenda Experimental Rafael Fernandes, da Universidade Federal Rural do Semi-Árido - UFERSA, Brasil. Os tratamentos consistiram da combinação de quatro doses de esterco bovino incorporadas ao solo: 15,0; 30,0; 45,0 e 60,0 t ha-1 em base seca, com quatro tempos de incorporação: 28; 49; 64 e 80 dias antes da semeadura do coentro - DAS, mais um tratamento controle (ausência de adubação). O delineamento experimental utilizado foi em blocos completos casualizados com os tratamentos arranjados em esquema fatorial 4 x 4 + 1 com 3 repetições. A cultivar de coentro utilizado foi a Verdão e as variáveis determinadas foram altura e número de hastes por planta e rendimento de coentro. O coentro respondeu à aplicação de esterco bovino, produzindo rendimentos máximos de 6453 e 6349 kg ha-1 de massa verde, com a dose de 60 t ha-1 e aos quarenta e seis dias de incorporação antes da semeadura, respectivamente.

ABSTRACT The use of manure is very important to family farmers who produce coriander in the region of Mossoró-RN, because this input is widely available and used by farmers. Aiming to evaluate the yield of the coriander fertilized with manure at different doses and incorporation times in the soil, a trial was conducted from September to November 2011, at the Experimental Farm Rafael Fernandes in the Universidade Federal Rural do Semi-Árido (UFERSA), Mossoró-RN, Brazil. The treatments consisted on the combination of four levels of manure incorporated into the soil: 15.0; 30.0; 45.0 and 60.0 t ha-1 at dry basis, with four incorporation times: 28; 49; 64 and 80 days before the coriander"s sowing - DAS, plus a control treatment (without fertilization). The experimental design was a randomized complete block with treatments arranged in a 4 x 4 + 1, with three replications. The coriander planted was the "Verdão" and the specific variables were height and number of stalks per plant and yield of the coriander. The coriander responded to the application of the manure, producing maximum yields of 6453 and 6349 kg ha-1 of fresh mass, with the dose of 60 t ha-1 and at forty-six days of incorporation before the sowing, respectively.

Phenotypic and Genotypic Characteristics of Rhizobia Isolated from Meknes-tafilalet Soils and Study of Their Ability to Nodulate Bituminaria bituminosa.

Aims: The objectives were to isolate and characterize phenotypically and genotypically the rhizobial strains from the soils belonging to the Meknes-Tafilalet region in order to select strains that are able to nodulate Bituminaria bituminosa. Study Design: An experimental study. Place and Duration of Study: Department of biology (Soil & Environment Microbiology Unit) Faculty of Sciences, Moulay Ismail University and Technical Support Unit for Scientific Research, CNRST in Rabat; between January and August 2010. Methodology: Samples from 23 different sites belonging to the Meknes-Tafilalet region were collected in order to select rhizobial strains that are able to nodulate Bituminaria bituminosa. The morphological, cultural and phenotypic parameters of isolated strains were studied. The phenotypic characteristics include colony morphology, growth speed, tolerances to temperature, salt and pH. To assess the genotypic diversity among the isolates, molecular characteristics based on 16S rDNA gene sequencing were performed. Results: The majority of the isolated strains showed fast-growing capacity (75%). Most strains tolerate neutral to alkaline pH, however some strains (18%) showed weak growth capacity at pH 4. All isolates were tolerant to high salt stress ([NaCl] = 3%). The genotypic characterization based on16S rDNA gene sequencing of the twelve strains showed a high diversity between the isolates. Conclusion: Taken together, our results highlight the important biodiversity of the isolated rhizobial strains and open opportunities for the development of new bio-fertilizer.