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Cedrela odorata is considered the second most invasive tree species of the Galapagos Islands. Although it is listed in CITES Appendix II and there are population losses in mainland Ecuador, in Galapagos it is paradoxically a species of concern due to its invasive potential. Genetic studies can shed light on the invasion history of introduced species causing effects on unique ecosystems like the Galapagos. We analyzed nine microsatellite markers in C. odorata individuals from Galapagos and mainland Ecuador to describe the genetic diversity and population structure of C. odorata in the Galapagos and to explore the origin and invasion history of this species. The genetic diversity found for C. odorata in Galapagos (H e = 0.55) was lower than reported in the mainland (H e = 0.81), but higher than other invasive insular plant species, which could indicate multiple introductions. Our results suggest that Ecuador's northern Coastal region is the most likely origin of the Galapagos C. odorata, although further genomic studies, like Whole Genome Sequencing, Rad-Seq, and/or Whole Genome SNP analyses, are needed to confirm this finding. Moreover, according to our proposed pathway scenarios, C. odorata was first introduced to San Cristobal and/or Santa Cruz from mainland Ecuador. After these initial introductions, C. odorata appears to have arrived to Isabela and Floreana from either San Cristobal or Santa Cruz. Here, we report the first genetic study of C. odorata in the Galapagos and the first attempt to unravel the invasion history of this species. The information obtained in this research could support management and control strategies to lessen the impact that C. odorata has on the islands' local flora and fauna.

Cedrela odorata es considerada la segunda especie más invasora de árboles en las Islas Galápagos. Esta especie está catalogada en el Apéndice II de CITES y sus poblaciones se encuentran amenazadas en Ecuador continental, pero paradójicamente en Galápagos es una especie de preocupación por su potencial invasor. Estudios genéticos pueden ayudar a entender la historia de invasión de especies introducidas que causan efectos en ecosistemas únicos como Galápagos. En este estudio, analizamos 9 marcadores microsatélites en individuos de Galápagos y Ecuador continental para describir la diversidad genética y estructura poblacional de C. odorata en Galápagos y explorar el origen e historia de invasión de esta especie. La diversidad genética encontrada para C. odorata en Galápagos (H e = 0.55) fue menor que la reportada en continente (H e = 0.81), pero mayor que la de otras especies de plantas insulares invasoras, lo que podría sugerir múltiples introducciones de esta especie a Galápagos. Nuestros resultados sugieren que la costa norte ecuatoriana es el origen más probable de C. odorata en Galápagos, aunque más estudios, como secuenciación del genoma completo, Rad­Seq y/o análisis de SNPs, son necesarios para confirmar este hecho. Además, de acuerdo con los escenarios propuestos, es posible que C. odorata haya sido introducida primero a San Cristóbal y/o Santa Cruz desde Ecuador continental. Después de estas introducciones iniciales, parece haber llegado a Isabela y Floreana desde San Cristóbal o Santa Cruz. Este es el primer estudio genético de C. odorata en Galápagos y el primer intento de esclarecer la historia de invasión de esta especie. La información obtenida en esta investigación podría apoyar estrategias de manejo para disminuir el impacto que C. odorata tiene sobre la flora y fauna nativa de estas islas.

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The following protocol introduces a targeted methodological approach of differential gene expression analysis, which is particularly beneficial in the context of non-model species. While we acknowledge that biological complexity often involves the interplay of multiple genes in any given biological response our method provides a strategy to streamline this complexity, enabling researchers to focus on a more manageable subset of genes of interest. In this context, red cedar transcriptome (Cedrela odorata L.) and known or hypothetical genes related to the response to herbivory were used as reference. The protocol key points are:•Implementation of a transcriptome thinning process to eliminate redundant and non-coding sequences, optimizing the analysis and reducing processing time.•Use of a custom gene database to identify and retain coding sequences with high precision.•Focus on specific genes of interest, allowing a more targeted analysis for specific experimental conditions. This approach holds particular value for pilot studies, research with limited resources, or when rapid identification and validation of candidate genes are needed in species without a reference genome.

RESUMO

Damage by Hypsipyla grandella Zeller restricts the success of plantations of Cedrela odorata. The most critical and vulnerable infection period by H. grandella is during the first three years. The aim was to estimate the expected genetic gain for the selection of clones of fast growth and resistant to the attack by this insect. A trial with 40 clones produced by grafting was planted in Veracruz, Mexico. Heritability, genetic correlations and genetic gain of clones were estimated with data at two years-old. The survival rate of the trial was of 97 % (466 living ramets in total), 2.84 m in total high and 2.32 cm of average normal diameter. Aditionally, 9.9 % of the ramets did not present attacks, indication of evasion, and 0.6 percent without response to attack. With response to attack 89.5 % of the ramets (several degrees of tolerance): 29 % with a single shoot, 14.2 % with several shoots and 46.3 % with a dominant shoot of several shoots formed. The clonal heritability of normal diameter, height, volume, stem taper index, number of attacks and response to the attack was H2c = 0.81, 0.80, 0.81, 0.61, 0.34, and 0.26. The genetic correlations between height, diameter and volume were ≥ 0.95, and the correlation of the volume with the incidence and the response to the attack was rg = -0.31 and rg = 0.62, that is a decrease in number of attacks and moderate increase in tolerance. With a selection intensity of 10 %, selecting the four clones with higher volume will produce a genetic gain of 82 % for volume, a decrease of 10.9 % of number of attacks and 6.3 % of better recovery from damage; this is more tolerance to the insect attack. The genetic gain justifies the use of the best clones in commercial plantations in Veracruz, Mexico.

El daño por Hypsipyla grandella limita el éxito de las plantaciones de Cedrela odorata. El periodo más crítico y vulnerable es durante los primeros tres años. El objetivo del estudio fue estimar la ganancia genética esperada en la selección de clones de mayor crecimiento y resistentes al ataque del insecto. Un ensayo de 40 clones producidos por injertos fue plantado en Veracruz, México. Con datos a la edad de dos años se estimaron: la heredabilidad, correlaciones genéticas y ganancia genética de los clones. El ensayo presentó una supervivencia del 97 % (466 rametos vivos en total), con 2.84 m de altura y 2.32 cm de diámetro normal promedio. El 9.9 % de los rametos no presentaron ataques, indicando evasión, y se estimó un 0.6 % sin respuesta al ataque. Con respuesta al ataque 89.5 % de los rametos (diferentes niveles de tolerancia): 29 % con un solo brote, 14.2 % con varios brotes, y 46.3 % con un brote dominante de varios brotes formados. La heredabilidad clonal del diámetro normal, altura, volumen, índice de conicidad, número de ataques y respuesta al ataque fue de H2 c = 0.81, 0.80, 0.81, 0.61, 0.34 y 0.26, respectivamente. Las correlaciones genéticas entre la altura, diámetro y volumen fueron ≥ 0.95, y del volumen con la incidencia y la respuesta al ataque de rg = -0.31 y rg = 0.62, es decir se presentó una disminución en el número de ataques y el aumento moderado en la tolerancia. Con una intensidad de selección del 10 %, seleccionando los cuatro clones de mayor volumen se obtuvo una ganancia genética de 82 % para el volumen, una disminución de 10.9 % de ataques y 6.3 % mejor recuperación del daño, esto es más tolerancia al ataque del insecto. La ganancia genética justifica la utilización de los mejores clones en plantaciones comerciales para Veracruz.

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Isotopes in tropical trees rings can improve our understanding of tree responses to climate. We assessed how climate and growing conditions affect tree-ring oxygen and carbon isotopes (δ18OTR and δ13CTR) in four Amazon trees. We analysed within-ring isotope variation for two terra firme (non-flooded) and two floodplain trees growing at sites with varying seasonality. We find distinct intra-annual patterns of δ18OTR and δ13CTR driven mostly by seasonal variation in weather and source water δ18O. Seasonal variation in isotopes was lowest for the tree growing under the wettest conditions. Tree ring cellulose isotope models based on existing theory reproduced well observed within-ring variation with possible contributions of both stomatal and mesophyll conductance to variation in δ13CTR. Climate analysis reveal that terra firme δ18OTR signals were related to basin-wide precipitation, indicating a source water δ18O influence, while floodplain trees recorded leaf enrichment effects related to local climate. Thus, intrinsically different processes (source water vs leaf enrichment) affect δ18OTR in the two different species analysed. These differences are likely a result of both species-specific traits and of the contrasting growing conditions in the floodplains and terra firme environments. Simultaneous analysis of δ13CTR and δ18OTR supports this interpretation as it shows strongly similar intra-annual patterns for both isotopes in the floodplain trees arising from a common control by leaf stomatal conductance, while terra firme trees showed less covariation between the two isotopes. Our results are interesting from a plant physiological perspective and have implications for climate reconstructions as trees record intrinsically different processes.

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Cedrela odorata (Meliaceae) is a native timber tree to Tropical America, known for its high-quality wood, unfortunately, plantations of this species are severely attacked by Hypsipyla grandella. The attraction or repellency of this pest is related to secondary metabolites such as phenols and limonoids (triterpenes); therefore, it is important to study these compounds to understand the phytochemical phenomena behind this problem. With this aim, the concentration of total phenols and limonoides was evaluated in C. odorata leaves from a plantation established in Tezonapa Veracruz, Mexico. For this, a total of 66 tree leaves samples, from seven sites, were analyzed. Phenols and limonoids concentration showed significant differences not only among different provenances, but also among individual trees of the same site (Tukey, p≤0.05). Phenols concentration was variable and in the range from 49 to 223mg EAG/g e for total phenols, from 7 to 158mg EC/g e for flavonoids and from 4 to 104mg EC/g e for proanthocyanidins. Limonoids concentration was also variable, ranging between 227 and 748mg EL/g e. A major compound was found by High-Performance Liquid Chromatography with Ultraviolet Diode Array Detection (HPLC-UV-DAD), which corresponded to a flavonol kaempferol glycoside derivative; additionally, a flavanol catechin was also detected at low concentrations. GC-MS allowed the identification of the sesquiterpenoids β-elemene, E-caryophyllene, aromadendrene, α-humulene, γ-cadinene, D-germacrene, bicyclogermacrene, and the poly terpenoids D-α-tocopherol and β-sitosterol. Our results suggest that the evaluation of phenols may play an important role as a selection parameter for improvement and conservation programs, if they are complemented with conventional breeding practices.

Cedrela odorata (Meliaceae) es una especie forestal maderable nativa de América Tropical, conocida por la alta calidad de su madera. Plantaciones de esta especie son atacadas severamente por Hypsipyla grandella; la atracción o repelencia de la plaga está relacionada con metabolitos secundarios tipo fenoles y limonoides (triterpenos), por lo que el estudio de estos compuestos es importante para comprender algunos fenómenos fitoquímicos. Se evaluó la concentración de fenoles totales y limonoides en hojas de C. odorata (Meliaceae) de una plantación establecida en Tezonapa Veracruz México, se analizaron 66 individuos de siete procedencias. La concentración de fenoles y limonoides mostró diferencias significativas, no solo entre las procedencias sino también entre los árboles de una determinada procedencia (Tukey, p≤0.05). La concentración de fenoles totales varió de 49 a 223mg EAG/g e, los flavonoides de 7 a 158mg EC/g e y las proantocianidinas de 4 a 104mg EC/g e, mientras que en limonoides se obtuvieron valores de 227 a 748mg EL/g e. Mediante Cromatografía Líquida de Alta Resolución con detector UV-Arreglo de Diodos (HPLC-UV-DAD) se encontró un compuesto mayoritario que corresponde a un flavonol de tipo glicósido de Kaempferol y se identificó el flavanol catequina a bajas concentraciones. Por medio de Cromatografía de Gases-Espectrometría de Masas (CG-MS) se identificaron los sesquiterpenos β-elemeno, E-cariofileno, aromadendreno, humuleno, gama-cadineno, D-germacreno, biciclogermacreno y los poli terpenos Di-α-Tocoferol y β-sitosterol. Nuestros resultados sugieren que la evaluación de los fenoles puede desempeñar un papel importante como parámetro de selección en programas de mejora y conservación, si se complementan con las prácticas convencionales de mejoramiento genético.

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A recuperação de áreas degradadas tem o objetivo de fornecer ao ambiente degradado condições favoráveis a reestruturação em um ambiente que não tem condições de se regenerar por si só, sendo o plantio de mudas arbóreas uma forma efetiva de ampliar este processo. Entretanto as espécies arbóreas nativas têm ritmo de crescimento lento, o que aumenta o tempo da produção da muda, como também diminui a competitividade destas com as plantas daninhas em áreas de implantação de florestas. O objetivo deste estudo foi avaliar os efeitos da aplicação de subdoses de glyphosate no desenvolvimento de mudas de Psidium cattleyanum (araçá-amarelo), Citharexylum myrianthum (pau-viola) e Cedrela odorata (cedrinho), através da análise de seus parâmetros morfofisiológicos. O experimento foi instalado e conduzido em casa de vegetação, e as unidades experimentais foram constituídas de uma planta, conduzida em vasos com capacidade para 2,5L, dispostos inteiramente ao acaso, arranjados em uma esquema fatorial (doses x espécies), com seis repetições. Os tratamentos foram constituídos da aplicação herbicida glyphosate nas seguintes subdoses: 0; 7,5; 15; 30 e 60 g e.a. ha-1, na formulação comercial Scout®. A aplicação nas mudas foi realizada aos 120 dias após germinação. Foram realizadas avaliações dos efeitos dos tratamentos químicos (fitointoxicação) sobre as plantas aos 7, 14 e 21 dias após aplicação, e após 90 dias foram avaliados a sobrevivência das plantas, condutância estomática, altura, diâmetro do caule e massa seca de parte aérea. As diferentes doses do herbicida não provocaram intoxicação às plantas. Já a dose de 30 e 60 g e.a. ha-1 proporcionou maiores incrementos em altura e diâmetro, bem como maiores massas secas em plantas de pau-viola e araçá-amarelo, respectivamente.

Recovery of degraded areas aims to provide the degraded environment favorable conditions for restructuring in an environment that is unable to regenerate itself and planting of tree seedlings is one of the effective ways to extend this process. However, native tree species have slow growth rate which increases the seedlings production time as well as decreases their competitiveness with weeds in areas of forests deployment. The aim of this study was to evaluate the effects of glyphosate reduced rates application on Psidium cattleyanum (yellow guava), Citharexylum myrianthum (pau-viola) and Cedrela odorata (cedro) seedlings development by analyzing its morphophysiological parameters. The experiment was carried out in greenhouse conditions and the experimental units consisted of one plant were conducted in 2.5L plastic pots and arranged in a completely randomized design with six replications. Treatments consisted of glyphosate application at 0, 7.5, 15, 30 and 60 g ha-1 using Scout® commercial formulation. Treatments application on these species seedlings was realized 120 days after seeds germination. Visual evaluations of plants phytotoxicity were realized at 7, 14 and 21 days after treatments application and plants survival, stomatal conductance, height, stem diameter and dry mass of shoots were evaluated 90 days after treatments application. Different doses of glyphosate did not cause plants phytotoxicity. Already, 30 and 60 g ha-1 of glyphosate provided greater increases in height, stem diameter and dry mass of shoots for Citharexylum myrianthum and Psidium cattleyanum, respectively.

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Este estudio tuvo por objetivo relacionar la estructura anatómica foliar con las características ecofisiológicas de Cordia thaisiana (Boraginaceae), Cedrela odorata y Swietenia macrophylla (Meliaceae) y Tabebuia rosea (Bignoniaceae) durante la fase de establecimiento (<2 años), cultivadas en una región al Sur del Lago de Maracaibo, Venezuela. Se realizaron cortes transversales de las láminas foliares, tinciones, mediciones de intercambio gaseoso (CO2 y H2O) y mediciones de crecimiento. Todas las especies presentaron hojas hipoestomáticas, con epidermis uniestratificada en ambas caras, mesófilo bifacial, parénquima esponjoso medianamente laxo y estomas anomocíticos. Se detectaron diferencias significativas para las variables número de estomas/mm², espesores de lámina foliar, parénquima en empalizada, parénquima esponjoso y epidermis. La mayor tasa de asimilación (A) de CO2 ocurrió en C. odorata y la menor en C. thaisiana. Esta última especie presentó los mejores rendimientos en crecimiento diametral y longitudinal, y, en consecuencia, es la especie más apta para integrar plantaciones agroforestales en el sitio estudiado.

The aim of the study was to compare anatomical structure of the leaves and ecophysiological traits of the species Cordia thaisiana (Boraginaceae), Cedrela odorata, Swietenia macrophylla (Meliaceae) and Tabebuia rosea (Bignoniaceae) cultivated in the South of the Maracaibo Lake, Venezuela. Transverse leaf sections were prepared and stained, and gas exchange (CO2 and H2O) and growth were measured. All the species had hypostomatics leaves with monostratified epidermis at both surfaces, bifacial mesophyll moderately lax spongy parenchyma, and anomocytic stomata. Significant differences were found for the number of stomata/mm² and leaf thickness, as well as palisade, spongy parenchyma and epidermis thicknesses. The gas exchange parameters showed that C. odorata has the highest photosynthetic rate (A) and C. thaisiana the lowest rate. The latter species presented better yields, with higher diametrical and length growth, being thus recommended for agroforestry plantations in the studied site.

Este estudo teve por objetivo relacionar a estrutura anatômica foliar com as características ecofisiológicas de Cordia thaisiana (Boraginaceae), Cedrela odorata e Swietenia macrophylla (Meliaceae) e Tabebuia rosea (Bignoniaceae) durante a fase de estabelecimento (<2 anos), cultivadas em uma região ao Sul do Lago de Maracaibo, Venezuela. Realizaram-se cortes transversais das lâminas foliares, tinção, medições de intercâmbio gasoso (CO2 e H2O) e medições de crescimento. Todas as espécies apresentaram folhas hipoestomáticas, com epiderme uniestratificada em ambas caras, mesófilo bifacial, parênquima esponjoso medianamente laxo e estomatos anomocíticos. Detectaram-se diferenças significativas para as variáveis número de estomas/mm², espessores de lâmina foliar, parênquima em empalizada, parênquima esponjoso e epiderme. A maior taxa de assimilação (A) de CO2 ocorreu em C. odorata e a menor em C. thaisiana. Esta última espécie apresentou os melhores rendimentos em crescimento diametral e longitudinal, e, em consequência, é a espécie mais apta para integrar plantações agroflorestais na área estudada.

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We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, δD, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata) having different architecture and phenology were studied. Average tree height was 8.9 and 7.6 m, respectively. Each tree species was grown in monoculture and in polyculture with 2 perennial monocotyledons (Euterpe oleracea and Heliconia imbricata). Maximum rooting depth at the time of δD determination was ~ 2 m for almost all species. Most roots of all species were concentrated in the upper soil layers. Stomatal conductance to water vapor (gS) was higher in the deciduous C. odorata than in the evergreen H. alchorneoides; within each species, gS did not differ when the trees were grown in mono or in polyculture. During the rainy season, gradients in soil water δD were not observed. Average rainy season xylem sap δD did not differ among members of the plant combinations tested (-30 ‰), and was more similar to δD values of shallow soil water. Under dry conditions, volumetric soil water content declined from 50 to ~ 35%, and modest gradients in soil water δD were observed. xylem sap δD obtained during dry conditions was significantly lower than rainy season values. xylem sap δD of plants growing in the four associations varied between -9 and -22‰, indicating that shallow water was predominantly absorbed during the dry period too. Differences in xylem sap δD of trees and monocots were also detected, but no significant patterns emerged. The results suggest that: a) the plant associations examined extracted water predominantly from shallow soil layers (<1 m), b) the natural isotopic variation in soil and plant water at the study site was low, and c) the plant mixes obtain water from more than a single soil layer simultaneously. Temporal factors were important in determining the competition and complementary relations observed among the trees and the perennial monocots. Under the prevailing environmental conditions, water use in these plant associations was determined largely by species-specific attributes such as biomass allocation to fine roots, phenology, and canopy architecture, and to a lesser extent by water limitations. Rev. Biol. Trop. 56 (4): 1947-1957. Epub 2008 December 12.

Examinamos los patrones de uso de agua del suelo de cuatro asociaciones vegetales establecidas en el Caribe norte de Costa Rica, comparando la composición isotópica del hidrógeno, δD, en la savia del xilema y en el agua del suelo en condiciones lluviosas y secas. Estudiamos cuatro asociaciones de cinco años de edad compuestas por dos árboles (Hyeronima alchorneoides y Cedrela odorata) con diferente arquitectura y fenología, cultivados en mono y policultivo con dos monocotiledóneas perennes (Euterpe oleracea y Heliconia imbricata). Las excavaciones mostraron que la profundidad máxima de las raíces fue de 2 m para casi todas las especies, y que la mayor densidad de raíces se encontraba en la superficie del suelo. La conductividad estomática (gS) fue mayor en el árbol caducifolio (C. odorata) que en el perennifolio (H. alchorneoides); dentro de cada especie, gS no difirió cuando los árboles fueron cultivados en mono o en policultivo. Los resultados sugieren que: a) las asociaciones examinadas extrajeron agua predominantemente de las capas superficiales del suelo (<1 m), b) la variación natural en el acceso al agua del suelo por parte de las especies, y en las propiedades del suelo, fue baja, y c) las combinaciones de plantas obtuvieron agua de varias capas del perfil del suelo simultáneamente. Los factores relacionados con el tiempo fueron importantes en la determinación de las relaciones de competencia y complementariedad observadas entre los árboles y las monocotiledóneas perennes. En las condiciones ambientales prevalecientes, el uso del agua por parte de estas asociaciones de plantas fue determinado más por atributos, como la asignación de biomasa a las raíces finas, la fenología, y las propiedades del dosel, que por limitaciones en la disponibilidad de agua.

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