Physical quality of seeds of Moquiniastrum polymorphum / Qualidade física de sementes de Moquiniastrum polymorphum

Abstract This study aimed to analyze the physical properties of the seeds of Moquiniastrum polymorphum when processed by mini-SAS, X-ray and seed blower systems. The seeds were purchased from Seeds Caiçara, located in Penápolis-SP. After purchase, the seed lot was characterized by standard tests. In the X-ray test the seeds were classified according to their internal morphology as filled, unfilled or malformed. The seed blower was set at six opening settings, resulting in light and heavy fractions. The evaluations were performed by weighing the seeds that remained in the blower (heavy fraction) and by the amount of filled seeds indicated by the X-ray test. The germination tests were composed of four replicates of 50 seeds. The mini-SAS was used for external evaluation. It was concluded that the combined use of the seed blower and the X-ray test was efficient for the evaluation and determination of the physical quality of the seeds of M. polymorphum. The seed blower at opening settings 5 resulted in the best lot quality. The external parameters were not able to qualitatively evaluate the seeds of M. polymorphum.

Resumo O presente estudo objetivou analisar as propriedades físicas das sementes de Moquiniastrum polymorphum por meio dos equipamentos raios-X, mini-SAS e soprador de sementes. As sementes foram adquiridas da empresa Sementes Caiçara em matrizes localizadas no município de Penápolis-SP. Após adquirido e beneficiado, o lote de sementes foi caracterizado por meio de testes padrões. No teste de raios-X as sementes foram classificadas de acordo com sua morfologia interna como cheias, vazias ou mal formadas. O soprador de sementes foi ajustado em seis aberturas, resultando em frações leves e pesadas. As avaliações foram realizadas pesando-se as sementes que permaneceram no soprador (fração pesada) e pela quantidade de sementes cheias pela análise de raios-X. Posteriormente foram realizados testes de germinação compostos por quatro repetições de 50 sementes. Na avaliação externa das sementes utilizou-se o equipamento mini-SAS. Após análise dos dados, concluiu-se que a utilização em conjunto dos equipamentos soprador de sementes e raios-X foi eficiente para avaliação e determinação da qualidade física das sementes de M. polymorphum. O soprador de sementes na regulagem da abertura 5 resultou na melhor qualidade do lote. Os parâmetros externos não foram capazes de avaliar qualitativamente as sementes de M. polymorphum.

Insect galls from Córdoba, Argentina: a case where stem galls predomínate / Agallas de insectos en Córdoba, Argentina: un caso en el que predominan las agallas caulinares

Abstract Galls are structures produced by plants in response to the activity of several types of organisms. Gall-inducing species have a close relationship with their host plant, as their habitat is largely restricted to the gall and the plant organ in which it develops. All plant organs are susceptible to gall induction by insects, the leaves being the most vulnerable. Knowledge about interactions between gall-inducing insects and plants is fragmented and incomplete in Argentina. In this study, we completed an inventory of galls induced by insects on plants in Córdoba (central Argentina) using information from field surveys and a review of the literature. We also focused on the frequency of plant-insect taxonomic associations and plant organs most commonly attacked by gall-inducing insects. Field surveys were performed systematically in 26 sites of Chaco Serrano, which were visited five times in two consecutive years, and in 17 sites of the province, which were sampled one or two times each. A comprehensive literature search of electronic and conventional databases was also conducted to complete the inventory. A total of 99 gall morphospecies on 58 plant species (21 families and 44 genera) were recorded through both field surveys and a literature review, enlarging the list of species available for the region by almost 50 %. Asteraceae and Fabaceae were the plant families most attacked by galling insects, in partial concordance with the most species-rich plant families in the region. Diptera, particularly the family Cecidomyiidae, was the most species-rich group in the community of galling insects, which is in agreement with different studies across the globe. Baccharis was the genus displaying the highest number of gall morphotypes, followed by Acacia, Condalia, Geoffroea, Prosopis and Schinus. Almost 60 % of the morphotypes were stem galls, a pattern uncommon in the literature. Fusiform and globoid-shaped galls were predominant. Our study highlights the scarce knowledge there is about the interactions between plants and gall-inducing insects in Argentina, particularly those involving species of Cecidomyiidae, with more than 30 undescribed species. Possible mechanisms involved in the predominance of stem galls in central Argentina are discussed. Rev. Biol. Trop. 66(3): 1135-1148. Epub 2018 September 01.

Resumen Las agallas son estructuras producidas por las plantas en respuesta a la actividad de diversos tipos de organismos, los cuales establecen una estrecha relación con sus especies hospedantes, ya que su hábitat está restringido en gran medida a la agalla y al órgano vegetal donde la agalla se desarrolla. Todos los órganos vegetales son susceptibles a la inducción de agallas por insectos, siendo las hojas los más frecuentemente atacados. En Argentina, el conocimiento de estas interacciones es fragmentando e incompleto. En el presente estudio, se realizó un inventario de agallas inducidas por insectos utilizando información obtenida de muestreos a campo y revisión bibliográfica. También nos enfocamos en las asociaciones taxonómicas insecto-planta más frecuentes y en los órganos vegetales más atacados por los insectos cecidógenos. Se realizaron muestreos a campo en 26 sitios localizados en el Chaco Serrano, que fueron visitados cinco veces en dos años consecutivos y en otros 17 sitios, distribuidos en la provincia de Córdoba, que fueron visitados una o dos veces. Además se realizó una exhaustiva revisión bibliográfica en bases de datos electrónicas (disponibles en internet) y convencionales. Un total de 99 agallas en 58 especies vegetales (21 familias y 44 géneros) fueron registradas a través de los muestreos en el campo y la revisión bibliográfica, ampliando el número de interacciones previamente conocidas en al menos un 50 %. Las familias vegetales más atacadas fueron Asteraceae y Fabaceae, coincidiendo con las familias vegetales más diversas de la región. La familia Cecidomyiidae (Diptera) presentó el mayor número de especies, en concordancia con diversos estudios alrededor del mundo. Baccharis fue el género vegetal que mayor número de morfotipos de agallas albergó, seguido por Acacia, Condalia, Geoffroea, Prosopis y Schinus. Al menos el 60 % de morfotipos registrados se presentaron en tallos, un patrón poco común en la bibliografía. Las formas predominantes fueron fusiforme y globoide. Nuestra investigación revela el escaso conocimiento sobre la comunidad de insectos cecidógenos y sus agallas en Argentina, particularmente de las inducidas por especies de la familia Cecidomyiidae, con más de 30 especies aún no descritas. Se discuten posibles mecanismos involucrados en la predominancia de agallas caulinares en el centro de Argentina.

Micropropagation of Baccharis antioquensis (Asteraceae) and photoinduction of polyphenols by UV radiation / Micropropagación de Baccharis antioquensis (Asteraceae) y fotoinducción de polifenoles mediante radiación UV

Abstract Polyphenols are a large diversity of chemical types and interactions that can be responsible for a multiplicity of protective functions ranging from toxicity and light/UV shielding to signal transduction. Bacharis antioquensis has been described as a potential source of new photoprotective compounds with antioxidant capacity associated to polyphenols compounds. The aim of the present work was to develop a micropropagation protocol of B. antioquensis and evaluate the production of polyphenols by in vitro plants exposure to UVB radiation. Branches in juvenile stage of B. antioquensis were collected, desinfected and cultured on half strength Murashige and Skoog medium, supplemented or not with growth regulators (TDZ, BA or GA3) on light/darkness conditions and liquid/solid media. After UV treatments, the absorption coefficient in the UVA-UVB range, the antioxidant capacity and the total phenol content (TPC) from all tissue cultures and the wild tissue were evaluated. Growth regulators, light conditions and type of culture medium (solid or liquid) had a favorable effect on the response of explants. Treatments containing BA + GA3 regulators (2 and 0.5 mg/L respectively) and TDZ (0.5 mg/L) showed positive results in bud growth in liquid medium and darkness. Results showed that UVR exhibited promoting effects on the accumulation of polyphenols, enhancing the absorption coefficient in the UVA-UVB range, the antiradical capacity and the TPC of B. antioquensis in vitro plants. Rev. Biol. Trop. 66(2): 754-764. Epub 2018 June 01.

Resumen Los polifenoles son compuestos químicos con una diversidad de interacciones que pueden ser responsables de muchas funciones, que van desde la toxicidad hasta la protección y blindaje contra la luz/UV. Baccharis antioquensis es una fuente potencial de compuestos fotoprotectores con capacidad antioxidante. El objetivo del presente trabajo fue desarrollar un protocolo de micropropagación para B. antioquensis y evaluar la producción de polifenoles in vitro por exposición a la radiación UVB. Ramas juveniles fueron colectadas y cultivadas en medio de Murashige y Skoog (MS) y suplementadas o no con reguladores de crecimiento (TDZ, BA o GA3) en diferentes condiciones de luz/oscuridad y medios líquidos/sólidos. Después de los tratamientos UVR, se midió el espectro de absorción UV y se evaluó el coeficiente de absorción en la región UVA-UVB, la capacidad antioxidante y TPC tanto en las plantas in vitro como en las plantas silvestres. Los tratamientos que contenían reguladores BA + GA3 (2 y 0.5 mg / L respectivamente) y TDZ (0.5 mg / L) mostraron resultados positivos en el crecimiento del brote en medio líquido y en condiciones de oscuridad. Los resultados mostraron que la UVR tiene efectos promotores sobre la acumulación de metabolitos secundarios, aumentando el coeficiente de absorción en la región UVA-UVB, la capacidad antiradicalaria y TPC en las plantas in vitro.

Propagación vegetativa por estacas de dasyphyllum diacanthoidesmediante recursos endogenos. una aproximación agroecológica / Cutting vegetative propagation of dasyphyllum diacanthoides, with endogenous resources: an agroecological approach

La evidencia empírica obtenida por los agricultores del sector de Huechelepún (comuna de Melipeuco, Región de La Araucanía, Chile) indica que la especie Dasyphyllum diacanthoides, además de presentar propiedades medicinales, es una alternativa forrajera invernal. Esta propiedad junto con su condición de especie endémica de los bosques de Chile obliga a compatibilizar el uso y la conservación de esta especie. El objetivo de este estudio fue propagar D. diacanthoides mediante esquejes semilignificados y determinar el efecto de la presencia de espinas en los esquejes y la exposición Norte o Sur de las plantas madres en el enraizamiento. El estudio se realizó utilizando recursos endógenos, por lo que las variables evaluadas se determinaron sobre la base del conocimiento de los agricultores. El diseño experimental incluyó cuatro tratamientos: T1: estacas de plantas con exposición sur y espinas, T2: estacas de plantas con exposición sur sin espinas, T3: estacas de plantas con exposición norte sin espinas y T4: estacas de plantas con exposición norte con espinas. Cada tratamiento constó de 25 réplicas y se utilizó un diseño completo aleatorio para la ubicación de las estacas en el invernadero. Las estacas de plantas en laderas Norte tuvieron porcentajes mayores de sobrevivencia, enraizamiento y formación de callos que las de plantas en laderas S. La prueba U de Mann- Whitney evidenció diferencias significativas entre estacas con y sin espinas con exposición norte sólo para la longitud de raíces (p ≤ 0,05). La propagación vegetativa de D. diacanthoides mediante esquejes semilignificados es factible. Los mejores resultados se obtienen con estacas sin espinas de plantas madres con exposición Norte.

The empirical evidence obtained by farmers of Huechelepún area (commune of Melipeuco, La Araucania, Chile) indicates that the specie Dasyphyllum diacanthoides, besides presenting medicinal properties, is a winter forage alternative. This property along with its status as endemic forests of Chile requires reconciling the use and conservation of this species. The aim of this study was to propagate D. diacanthoides by semi lignified cuttings and determine the effect of the presence of thorns in the cuttings and North or South exposure mother plants in rooting. The study was performed using endogenous resources, so the evaluated variables were determined on the basis of knowledge of farmers. The experimental design included four treatments: T1: cuttings of plants with southern exposure and thorns, T2: Stakes southern exposure plants without thorns, T3: cuttings of plants with northern exposure spineless and T4: cuttings of plants with northern exposure with thorns. Each treatment consisted of 25 replicates and a complete randomized design for location of the cuttings in the greenhouse was used. Cuttings from plants in North slopes had higher percentages of survival, rooting and callus formation the plant on hillsides South. Mann-Whitney U test showed significant differences between stakes with and without spines north only exposure length roots (p ≤ 0.05). The vegetative propagation of cuttings D. diacanthoides by semi lignified is feasible. The best results are obtained with stakes thornless plants mothers with Northern exposure.

Adaptive variation of Patagonian Senecio patagonicus Hook. & Arn., Adesmia boronioides Hook.F. and Lepidophyllum cupressiforme (Lam.) Cass. as a plant response to environmental stress / Variación adaptativa en respuesta al estrés ambiental de Senecio patagonicus, Adesmia boronioides y Lepidophyllum cupressiforme que habitan en dos localidades de la Patagonia chilena

Different analyses were carried out on the following plant species: Adesmia boronioides Hook.F., Senecio patagonicus Hook. & Arn. and Lepidophyllum cupressiforme (Lam.) Cass. in order to compare the photosynthetic pigment, carotenoid and phenylpropanoid contents. Total phenolic content and antioxidant capacity were measured by using common established reagents: Folin-Ciocalteau and ABTS respectively. Plant samples were collected from specimens growing inside the National Park Pali Aike and the Botanic Garden Carl Skottsberg in Punta Arenas city. The results showed no marked tendencies between photosynthetic pigments. Nevertheless, a good correlation was found among the antioxidant capacity and phenolic compounds. Furthermore, species growing in the Pali Aike National Park seem to be more adapted to the environmental conditions.

Se realizaron diferentes análisis al contenido de pigmentos fotosintéticos, carotenoides y fenilpropanoides. El contenido de fenoles totales y la capacidad antioxidante se midieron usando reactivos ampliamente conocidos: Folin-Ciocalteau y ABTS respectivamente en las siguientes especies: Adesmia boronioides, Senecio patagonicus y Lepidophyllum cupressiforme. Estas plantas se encuentran en el Parque Nacional Pali Aike y en el Jardín Botánico Carl Skottsberg en la ciudad de Punta Arenas. Los resultados no muestran una tendencia clara entre las muestras de pigmentos fotosintéticos. Sin embargo, se pudo observar una buena correlación entre la capacidad antioxidante y el contenido de compuestos fenólicos. Además, aparentemente las especies que crecen en el Parque Nacional Pali Aike están más adaptadas a esas condiciones ambientales.

Reubicación de plantas de Espeletia grandiflora (Asteraceae) como estrategia para el enriquecimiento de áreas de páramo alteradas (PNN Chingaza, Colombia)

Relocation of Espeletia grandiflora (Asteraceae) plants as a strategy for enrichment of disturbed paramo areas (PNN Chingaza, Colombia). Ecological restoration of the Andean paramos faces several ecological barriers mainly at the phase of dispersal and establishment of native species. With the aim to contribute to the enrichment of degraded areas, different strategies have to be developed to overcome those barriers. In this work we studied the response of individuals of Espeletia grandiflora (Asteraceae) to the relocation as a strategy for ecological restoration programs. We also evaluated the effect of size of relocated individuals on their survival and development. The work was carried out in an experimental plot at 3 424m altitude in the sector Lagunas de Siecha of Chingaza National Park, Colombia. We relocated 200 plants that belonged to three different size classes: 5, 10 and 15cm of initial height. The following variables were registered: survival, plant height, number of living leaves and stem diameter of each individual. We also evaluated the differences between individuals in survival and development. In terms of survival the most efficient size classes corresponded to 15cm high; the survival was 85% after two years. The relative growth rates for height and stem diameter decreases with the increase in size, but the absolute increase in height did not show significant differences between the three sizes tested. Since the stem diameter was found the strongest survival predictor after two years of relocation activities, we suggest its use as a criterion for selection of relocation individuals. The relocation of individuals of E. grandiflora had a positive side effect, carrying other species that may contribute to the enrichment and restoration of degraded areas. Among these, we found species of the genus Hypericum, as well as Arcytophyllum nitidum and Calamagrostis effusa, which should be evaluated in terms of survival and development for the subsequent implementation of the relocation strategy. In this study we verified the successful relocation of individuals of E. grandiflora as a strategy for enrichment of paramos, and provided values of survival and growth, which should be useful for planning and predicting with greater certainty the success of restoration programs in the paramo.

El trasplante o reubicación de individuos ha sido ampliamente usado para la adición de especies en procesos de restauración. En este trabajo se estudió la respuesta de individuos de Espeletia grandiflora a la reubicación como estrategia de restauración ecológica; así mismo, se evaluó el efecto del tamaño de los individuos reubicados sobre la supervivencia y desarrollo. Se reubicaron individuos de tres diferentes tamaños, 5, 10 y 15cm de altura. Se registraron las variables supervivencia, altura de la planta, número de hojas vivas y diámetro del tallo de cada uno de los individuos, se evaluaron las posibles diferencias en cuanto a supervivencia y desarrollo. La categoría de tamaño más eficaz corresponde a la de 15cm de altura, que presentó una supervivencia del 85% luego de dos años. Se sugiere el uso del diámetro del tallo como criterio de selección de los individuos a reubicar, ya que es la variable que mejor predice la supervivencia dos años luego de la reubicación. Las tasas de crecimiento relativo en altura y diámetro del tallo disminuyen conforme aumenta el tamaño de los individuos; sin embargo, el incremento absoluto en altura no presenta diferencias entre los tres tamaños evaluados. A partir de los resultados se verifica el éxito de la reubicación de plantas de E. grandiflora como estrategia de enriquecimiento en pastizales de páramos alterados.

Rapid in vitro plant regeneration from leaf explants of Launaea sarmentosa (Willd.) Sch. Bip. ex Kuntze

An efficient protocol for organogenesis through leaves has been established for Launaea sarmentosa (Willd.) Sch. Bip. ex Kuntze, a highly valuable medicinal plant. The leaf explants produced microshoots on MS basal medium when fortified with cytokinins and auxins. A combination of 6-benzylaminopurine (BAP) at 0.5mg/l and naphthaleneacetic acid (NAA) at 0.2mg/l resulted in the induction of high frequency microshoots in 30 days. The microshoots were successfully subcultured for shoot elongation and eventually for rooting on MS medium supplemented with indole-3-butyric acid (IBA) at 0.5mg/l. The regenerated plantlets were hardened under greenhouse conditions and transferred to garden, resulting in a 90% survival rate.

Dimorphic cypsela germination and plant growth in Synedrella nodiflora (L.) Gaertn. (Asteraceae) / Germinação de cipselas dimórficas e crescimento de plantas de Synedrella nodiflora (L.) Gaertn. (Asteraceae)

Synedrella nodiflora is a weed species that has dimorphic cypselas: winged peripheral and lanceolate shaped central. The aim of this work is to describe the reproductive capability by measuring dimorphic cypselas morphology, imbibition rates and germinative patterns under temperature, light quality and water availability gradients, and compare the plant growth between two light treatments. The central cypselas were lighter, longer and its pappi were more elongated than the peripheral ones, favoring its dispersion. Neither type had deep dormancy and both of them germinated with the same pattern under the optimum conditions. Both cypselas showed higher germinability in temperatures between 25 and 30 °C, under white light and high water availability, although there are some differences between the types, mainly at dark treatments. Plants grown in direct sunlight accumulated more biomass, allowing for higher plant development and inflorescence production, although shaded light plants capitulum had a higher central: peripheral ratio than the direct sunlight treatment. S. nodiflora cypselas germinate better in unfiltered light places, although the plants are adapted to shady conditions. The species showed high germination potential over a wide range of environmental conditions, as well as fast plant development. All of these features favor distribution in environmental sites.

Synedrella nodiflora é uma planta daninha que possui cipselas dimórficas: periférica alada e central com forma lanceolada. O objetivo deste trabalho foi caracterizar a capacidade reprodutiva por medição da morfologia das cipselas, taxas de embebição e padrões germinativos sob gradientes de temperatura, qualidade de luz e disponibilidade de água, e comparação do crescimento das plantas sob dois tratamentos luminosos. As cipselas centrais foram mais leves, compridas e seus pappi foram mais alongados que as periféricas, o que favorece sua dispersão. Nenhum dos tipos exibiu dormência profunda, germinando sob o mesmo padrão nas condições ótimas. Ambas as cipselas apresentaram maior germinabilidade sob temperaturas entre 25 e 30 °C, sob luz branca e alta disponibilidade hídrica, apesar de haver algumas diferenças entre os tipos, principalmente em tratamentos de escuro. Plantas que cresceram em luz solar direta acumularam maior quantidade de biomassa, permitindo o maior desenvolvimento vegetal e produção de inflorescências, contudo capítulos das plantas sombreadas tiveram uma razão central:periférica maior que tratamentos com luz direta. Cipselas de S. nodiflora germinam melhor em locais com luz não filtrada, contudo as plantas são adaptadas à condição de sombra. A espécie apresentou um alto potencial germinativo sob uma ampla gama de condições ambientais, assim como rápido desenvolvimento, todas essas características favorecem a distribuição ao longo dos ambientes.

Contrasting genetic diversity and differentiation of populations of two successional stages in a neotropical pioneer tree (Eremanthus erythropappus, Asteraceae)

Eremanthus erythropappus, commonly known as “candeia”, is an abundant pioneer tree species, forming dense populations known as “candeial”, but it is also found in forests at middle stages of succession. Trees from forests are bigger and occur in lower density than in the “candeial”. The objectives of the present study were to investigate if the decrease in population density during successional process is accompanied by 1) changes in within-population genetic diversity, and 2) differentiation of populations. Eight populations, four of early successional stage (“candeial”) and four of middle successional stages (forest), were analyzed with RAPD markers. The genetic diversity found was high compared to other tree species analyzed with RAPD markers. AMOVA revealed that most of the genetic variations of E. erythropappus were found within populations (85.7%), suggesting that this species is predominantly outcrossing. The relatively low differentiation among the populations can be attributed to small distances among the populations analyzed (0.2 to 10.8 km). No indication that populations from middle successional habitats show lower genetic variation than populations from early successional stages was found. The percentage of polymorphic fragments (82.8 and 84.8%) and the Shannon indexes (0.442 and 0.455) were similar in “candeial” and forest, respectively. These results suggest that if an increase in selection intensity occurred during succession, it did not result in a decrease in genetic diversity or that the selection effect was balanced by other factors, such as gene flow. Higher significant differentiation among E. erythropappus populations from “candeial” in relation to that among populations from forest was also not detected.

Efecto de las micorrizas arbusculares sobre el crecimiento y supervivencia de dos especies nativas de la gran sabana, al transplantarlas a un área degradada / Effect of arbuscular mycorrhizas on growth and survival of two plant species indigenous of la gran sabana, transplanted to a degraded area

El propósito de este trabajo fue determinar si la inoculación con hongos micorrízicos arbusculares produce un aumento en el crecimiento y la supervivencia de dos arbustos nativos de La Gran Sabana, al ser transplantados a un área degradada. Semillas pre-germinadas de Clusia pusilla (Clusiaceae) y Gongylolepis benthamiana (Asteraceae) fueron sometidas a dos tratamientos durante una etapa de vivero que se extendió por 5 meses. Dichos tratamientos fueron: M: inoculación con el hongo micorrízico arbuscular Glomus manihotis, junto con la adición de 20 kg.ha-1 de superfosfato triple (SFT) y F: fertilización con 100 kg.ha-1 de SFT. Al final de la etapa de vivero, las plántulas fueron transplantadas a un área afectada por la remoción de la capa superficial del suelo en Luepa, La Gran Sabana. Los resultados obtenidos muestran un comportamiento contrastante entre ambas especies. La inoculación con micorrizas (tratamiento M) produjo un aumento significativo en la supervivencia de C. pusilla, en comparación con el tratamiento donde únicamente se aplicó el fertilizante (tratamiento F). En contraste, la supervivencia de G. benthamiana no se vio afectada por la inoculación con micorrizas. Ambas especies difieren en el tamaño de sus semillas, área foliar específica y relación vástago raíz, aunque son similares en cuanto a la densidad de pelos radicales y el diámetro de sus raíces. Se concluye que C. pusilla es mucho más dependiente de las micorrizas que G. benthamiana y se propone que esa mayor dependencia está relacionada con el menor tamaño de sus semillas en comparación con las de G. benthamiana.

The aim of this work is to evaluate the effect of arbuscular mycorrhizal inoculation on the growth and survival of two species of shrub indigenous of La Gran Sabana, when were transplanted to a degraded area. Pre-germinated seeds of Clusia pusilla (Clusiaceae) and Gongylolepis benthamiana (Asteraceae) were subjected to two different treatments during 5 months in the nursery, before transplanting to the field: F: fertilized with 100 kg.ha-1 of triple superphosphate (TSP) and M: inoculated with the arbuscular mycorrhizal fungus Glomus manihotis, plus 20 kg.ha-1 of TSP. At the end of the nursery stage, seedlings were transplanted to a degraded area situated at Luepa, in La Gran Sabana. Results were contrasting between both species. Arbuscular mycorrhizal inoculation of C. pusilla (M treatment) increased significantly its survival in comparison with treatment F. In contrast, no effect was observed on the survival of G. benthamiana, after AM-inoculation. Both species are different regarding seed weight; specific leaf area and shoot/root relationship but they have no differences respect to hair root density or root diameter. We concluded that C. pusilla is more dependent on mycorrhizas for survival than G. benthamiana. We hypothesized that the higher mycorrhizal dependence showed by C. pusilla is attributable to its smaller seeds in comparison with those of G. benthamiana.