Leaf histology of greenhouse plants, in vitro cultured and somaticembryo-derived plants of Bactris gasipaes Kunth / Histologia de folhas de Bactris gasipaes Kunth de plantas de casa-de-vegetação, cultivadasin vitro e obtidas por embriogênese somática

In vitro cultures of peach palm (Bactris gasipaes Kunth) were established by somatic embryogenesis but some improvements in maturation and conversion steps are still needed. The aim of this study was to analyze morpho-anatomical differences in peach palm leaves from greenhouse cultured plants, in vitro plants developed from in vitro germinated seeds and somatic embryo-derived plants. Expanded leaves were prepared for histological analyses and scanning electron microscopy. No significant difference was found between ex vitro and in vitro cultured plants, but the somatic embryo-derived plants showed structural alterations of the leaves. The epidermal cells were elongated in shape, the mesophyll cells were thicker and the vascular bundle was not very developed. In somatic embryo-derived leaves the cuticle was thinner than in other leaves and epicuticular wax was present but poorly deposited. In in vitro cultured plants, the deposition of epicuticular wax on the leaves was irregular while in the greenhouse plants it was regular and abundant. These alterations in somatic embryo-derived leaves could hinder the acclimatization and development of peach palm plants so it is necessary to improve the protocol for somatic embryogenesis to produce better plants.

O cultivo de pupunha (Bactris gasipaes Kunth) in vitro foi estabelecido através de embriogênese somática; alguns melhoramentos nas fases de maturação e conversão, contudo, ainda são necessários. O objetivo deste trabalho foi analisar diferenças morfoanatômicas em suas folhas, cultivadas em casa de vegetação, germinadas in vitro e provenientes de embriogênese somática. Folhas expandidas foram preparadas para análise histológica e microscopia eletrônica. Houve diferenças significativas entre as plantas da casa de vegetação e as plantas obtidas por embriogênese somática. As células epidérmicas eram alongadas; a espessura da folha e do clorênquima era menor que nas outras; a cutícula era menos espessa, com baixa deposição de ceras. Os feixes vasculares estavam menos desenvolvidos. As folhas das plantas cultivadas in vitro e de embriogênese somática apresentavam estruturas pouco desenvolvidas, o que sugere a necessidade de uma melhoria na fase de conversão durante a embriogênese somática.

Micromorfología de los foliolos de pejibaye Bactris gasipaes (Arecaceae) var. Diamantes-10 / Micromorphology of pejibaye leaflets Bactris gasipaes (Arecaceae) var. diamonds-10

ResumenBactris gasipaes se cultiva ampliamente para el aprovechamiento del palmito y el consumo de los frutos En este trabajo se realizó una descripción de las características micro morfológicas de los foliolos de plantas adultas de la variedad sin espinas Diamantes-10 de B. gasipaes, recolectadas en la Estación Experimental Diamantes en Guápiles, Costa Rica. Se utilizó microscopía de luz, electrónica de barrido y de transmisión. Para el estudio se recolectaron 25 foliolos y se evidenció abundante cera epicuticular en la superficie adaxial y abaxial. La epidermis está compuesta de células isodiamétricas y las células de la hipodermis tienen forma rectangular y son de mayor tamaño que las de la epidermis, también se observaron células buliformes. Los foliolos son anfiestomáticos en las áreas intercostales y alternan con bandas de células epidérmicas. El mayor número de estomas se encuentra en la superficie abaxial. Estos foliolos presentan tres tipos de tricomas. El parénquima presenta varios estratos no muy bien definidos con presencia de astroesclereidas. También se observan haces de fibras entre el parénquima que forman grupos de células muy compactas. La vena central presenta varios haces vasculares, algunos dispuestos de forma continua y todos ellos se encuentran rodeados de una vaina de tejido esclerotizado, algunas de estas fibras presentaron protoplastos vivos. Todas las venas menores presentan la misma anatomía de los haces vasculares de la vena central. Los vasos del protoxilema y metaxilema tienen paredes laterales con ornamentaciones escalariformes. El floema se ubica hacia la superficie adaxial de la vena y en el corte se observaron las células cribosas y células compañeras rodeadas de células de parénquima y fibras. Las células compañeras presentaron plasmodesmatas ramificados unidos a un elemento criboso y en ellos se evidenció cuerpos de proteína, llamada proteína-P. La diferencia principal en la anatomía de los foliolos de la var. Diamantes-10 radica en la ausencia de espinas, pero en el resto de la morfología no parece presentar cambios morfológicos con el resto de las variedades de B. gasipaes K.

Abstract:Bactris gasipaes is widely cultivated for the consumption of palm hearts and fruits. The present work describes the micro morphological characteristics of leaflets from adult plants of B. gasipaes, thornless variety Diamantes-10, collected in the Diamantes Experimental Station in Guápiles, Costa Rica. We collected 25 leaflets and analyses were performed with a combination of microscopy techniques: light microscopy, scanning electron microscopy and transmission electron microscopy to study their structure. Our results showed that leaflets have abundant epicuticular wax on adaxial and abaxial surfaces. Analyses from the epidermis indicated that it is composed of isodiametric cells, and it is also evident that hypodermis cells have rectangular shape and are larger than the other epidermal cells. We observed stomata on both surfaces, but they were more abundant in the abaxial surface. On the other hand, the epidermis showed the presence of trichomes with three different morphologies. In the parenchyma, cells are large and not well defined, and we observed the presence of astroesclereids, and compact groups of fiber bundles between parenchyma cells. The central vein has several vascular bundles, arranged in a continuous manner, and they are surrounded by sclerotic tissue; some of these fibers presented live protoplasts. All minor veins showed the same anatomy as the central vein. In these veins, the vessel elements of protoxylem and metaxylem showed scalariform ornaments on their walls. Phloem is located towards the adaxial surface of the vein and we observed sieve and companion cells surrounded by fibers and parenchyma cells. The companion cells presented branched plasmodesmata attached to a sieve element, and in these elements we found protein bodies called P-protein. The main anatomical difference in the leaflets of the var. Diamantes-10, compared to the other varieties of B. gasipaes K, is the lack of thorns; the other morphological features seem to be conserved. Rev. Biol. Trop. 64 (3): 1273-1285. Epub 2016 September 01.

Longevity and germination of Syagrus romanzoffiana (Arecaceae) seeds and its ecological implications / Longevidad y germinación de semillas de Syagrus romanzoffiana (Arecaceae) y sus implicaciones ecológicas

Syagrus romanzoffiana is a palm tree native and widely distributed of South America. The present study investigated the longevity and germination of the buried seeds of this species in an experimental seed bank. Laboratory germination and viability tests were performed for comparison with field results. Pyrenes (seeds enclosed by the endocarp) were buried in a forest fragment edge in July 2012 (dry season) and exhumed monthly during one year, for the assessment of water content and percentage of germinated and viable seeds. Germination tests were conducted in a Mangelsdorf-type germinator at 30°C under constant light and the viability was assessed by the tetrazolium test. An additional sample of pyrenes was buried to evaluate the percentage of seedling emergence and survival. Climatic and soil moisture data were recorded. In the laboratory, the pyrenes were stored for one year in a temperature-controlled room at 20ºC and 75% (±10%) relative air humidity to assess changes in the percentage of germination and viability over time. In the field, a reduction in seed viability was observed over the study period, with a total loss of viability of non-germinated seeds at seven months after burial. The maximum germination (close to 26%) was observed in the samples that were exhumed between five and seven months after burial. In the field, seedling emergence did not exceed 10% and seedling mortality was not observed. The percentages of germination and of viable seeds decreased both in burial and stored seeds. The stored seeds maintained viability at up to six months, with marked reduction thereafter. After the germination tests (four months) in the laboratory, all of the remaining seeds were nonviable. The ecological, physiological and reproductive characteristics of the species are discussed, and we concluded that S. romanzoffiana seeds have short longevity after imbibition, and low potential for soil seed bank formation. Rev. Biol. Trop. 63 (2): 333-340. Epub 2015 June 01.

Syagrus romanzoffiana (Arecaceae) es una palma nativa y ampliamente distribuida de América del Sur. El presente estudio investigó la longevidad y la germinación de las semillas enterradas de esta especie en un banco experimental. Se realizaron pruebas de germinación y viabilidad de laboratorio para hacer una comparación con los resultados de campo. Pirenos (semillas encerradas por el endocarpio) fueron enterrados en el borde de un fragmento de bosque en julio (época seca) y exhumados mensualmente por un año, para la evaluación del contenido de agua y del porcentaje de semillas germinadas y viables. Las pruebas de germinación se realizaron en un germinador tipo Mangelsdorf a 30°C bajo luz constante y la evaluación de la viabilidad se realizó con la prueba de tetrazólio. Una muestra adicional de pirenos fue enterrada para evaluar el porcentaje de emergencia de las plántulas. Se tomaron los datos climáticos y se determinó la humedad del suelo. En el laboratorio, los pirenos se almacenaron durante un año en una sala de temperatura controlada a 20°C y 75% (±10%) de humedad relativa del aire, para evaluar los cambios en el porcentaje de germinación y la viabilidad en el tiempo. En el campo, se observó una reducción de la viabilidad de las semillas durante el período de estudio, con una pérdida total de la viabilidad de las semillas no germinadas a los siete meses después del entierro. La germinación máxima (cerca de 26%) se observó en las muestras que fueron exhumadas entre cinco y siete meses después del entierro. En el campo, la emergencia de las plántulas no superó el 10% y no se observó mortalidad de plántulas. Los porcentajes de germinación y de semillas viables disminuyeron tanto en el suelo como en el laboratorio. Las semillas almacenadas mantuvieron la viabilidad hasta por seis meses de almacenamiento, con una reducción marcada a partir de entonces. Después de las pruebas de germinación (cuatro meses) en el laboratorio, todas las semillas restantes eran inviables. Discutimos las características ecológicas, fisiológicas y reproductivas de la especie, y llegamos a la conclusión de que las semillas de S. romanzoffiana tienen corta duración después de la imbibición y bajo potencial de formación del banco de semillas en el suelo.

Estructura floral de dos especies de Trachycarpeae (Arecaceae) / Floral structure of two species of Trachycarpeae (Arecaceae)

Copernicia and Washingtonia are two genera of the Trachycarpeae for which no subtribal classification has been proposed, mainly because of the lack of resolution in phylogenetic studies. Morphology and anatomy of flowers whithin Coryphoideae have proven useful for taxa delimitation and supporting relationships among their members. A description of the morphological and anatomical structure of flowers of C. tectorum and W. filifera is presented in order to explore reproductive characters that may clarify their classification within the subfamily and to contribute with floral biology studies. Flowers of cultivated specimens of both taxa and developing fruits of C. tectorum were fixed in FAA, dissected for morphological analysis, and parafin-embedded flowers and fruits were serially sectioned for obtaining permanent slides, using conventional techniques and safranin-fast green staining. All procedures were carried out in the Laboratory of Morpho-Anatomy, Agronomy Faculty of the Universidad Central de Venezuela (UCV). Both species have hermaphroditic flowers. C. tectorum flowers have a thick and pubescent perianth, six stamens with filaments forming a tube fused to the corolla, with rounded projections and an acute apex where the anthers are inserted. W. filifera flowers have an irregularly dentate calyx, and a shortly acuminate corolla, six stamens united by their filaments to the corolla which at the same time are briefly fused to the gynoecium. Cells with druse crystals in the staminal tube are reported for C. tectorum. Only one of the carpels of the gynoecium of C. tectorum develops at fruit stage, and a layer of abundant raphide cells forming a crustaceous endocarp in mature fruits, was found. W. filifera presents the perianth mesophyll with few layers of thick walled cells and schlerenchymatic tissue, gynoecium with apically fused carpels in the ventral region of ovary, free at the base and the apex of the style, where the ventral sutures are opened. C. tectorum has a ventral hypodermis in the petals made of large and thick walled cells, gynoecium with apically fused carpels in the ovary, free and adpressed basally, style-stigma completely fused, and stylar transmission channel absent distally. Distinct stylar canals in C. tectorum, united distally in W. filifera confirm the close relationship between these species and subtribe Livistoninae. Also, some floral morpho-anatomical similarities (e.g. fleshy calyx base and a hypodermis with thickened cell walls in petals) were found between C. tectorum and Pritchardia, supporting the affinities between both genera. Rev. Biol. Trop. 62 (3): 1137-1146. Epub 2014 September 01.

Copernicia y Washingtonia son dos de los géneros de Trachycarpeae para los cuales no ha sido propuesta una clasificación subtribal debido a la carencia de resolución en los estudios filogenéticos. La morfología y anatomía floral dentro de Coryphoideae han sido útiles para la delimitación de taxones y apoyo de relaciones. En este trabajo se presenta una descripción de la estructura morfo-anatómica de las flores de C. tectorum y W. filifera, con la finalidad de explorar caracteres reproductivos que puedan aclarar su ubicación dentro de la subfamilia y contribuir con estudios de biología floral. Se fijaron flores de especimenes cultivados de ambos taxones y frutos en desarrollo de C. tectorum, se realizaron disecciones para las descripciones morfológicas y cortes anatómicos seriados para la obtención de láminas permanentes utilizando técnicas convencionales con parafina. Todos los procedimientos fueron llevados a cabo en el Laboratorio de Morfo-Anatomía, Facultad de Agronomía de la Universidad Central de Venezuela (UCV). Ambas especies tienen flores hermafroditas. Las flores de C. tectorum tienen perianto engrosado y pubescente. Las flores de W. filifera presentan un cáliz irregularmente dentado y corola corto-acuminada. Se reportan células con drusas en el tubo estaminal de C. tectorum. Uno solo de los carpelos de C. tectorum se desarrolla en fruto y se encontró una capa de células con rafidios que podrían formar el endocarpo crustáceo en los frutos maduros. W. filifera presenta pocas capas de células de paredes engrosadas y tejido esclerenquimático en el mesofilo del perianto, gineceo con carpelos fusionados en el ápice del ovario (en su porción ventral), libres en la base y en el ápice del estilo, donde presenta suturas ventrales abiertas. Los pétalos de C. tectorum poseen una hipodermis ventral de células con paredes muy engrosadas, gineceo con carpelos fusionados en el ápice del ovario, libres y adpresos en su base, región estilar-estigmática fusionada y canal de transmisión estilar ausente distalmente. La presencia de canales estilares separados en C. tectorum, unidos distalmente en W. filifera confirman la relación cercana de estas especies con la subtribu Livistoninae. Igualmente, se encontraron algunas similitudes entre C. tectorum y Pritchardia (p.e. base carnosa del cáliz y epidermis ventral con células de paredes engrosadas en los pétalos), apoyando ciertas afinidades entre ambos géneros.

Morphoanatomy of the flower of Syagrus inajai (SPRUCE) Becc. (Arecaceae- Arecoideae- Attaleinae), Amazon / Morfoanatomia floral de Syagrus inajai (Spruce) Becc. (Arecaceae- Arecoideae- Attaleinae), Amazônia

The occurrence of Syagrus inajai (Spruce) Becc., popularly known as pupunha palm, among other names, has been registered in the Guianas and in the North of Brazil in areas of terra firme (non-flooding) and gallery forests. In order to characterize the inflorescence and further knowledge of this family, a morphoanatomical study was carried out of the palm S. inajai in a green area of the Campus of the Federal University of Amazonas - UFAM, Manaus, Amazonas. The inflorescences are branched to one order, pedunculate, and interfoliar, measuring 62-82 cm in length, with woody bracts with longitudinal grooves on the external surface, and flowers in triads. The number of flowers to each inflorescence varies from 5,904 to 17,316 for staminate flowers, and from 180 to 3,528 for pistillate flowers. Staminate flowers with six anthers and one vascular bundle each; three-lobed pistillodium, vascularized pistillodium. Its pistillate flowers have six staminodia joined to form a circle, syncarpic, tricarpellary, trilocular gynoecium, one ovule to each locule, synascidiate in the ovary, and plicated above. Tripartite stigma, apical and sessile, with epidermis composed of elongated papillary cells, pattern of epidermis that is maintained throughout the stylar canal. Bitegmented, anatrope, pachychalazal ovule.

Syagrus inajai (Spruce) Becc., popularmente conhecida como pupunha-brava entre outras denominações, teve sua ocorrência registrada para Guianas e no norte do Brasil em áreas de floresta de terra firme e floresta de galeria. Com o intuito de caracterizar a inflorescência ampliando o conhecimento a respeito da família foi realizado o estudo morfoanatômico da palmeira S. inajai, em área verde do Campus da Universidade Federal do Amazonas - UFAM, Manaus, Amazonas. A inflorescência é ramificada em primeira ordem, pedunculada, interfoliar com 62-82 cm de comprimento, bráctea lenhosa com fissuras longitudinais na superfície externa e flores em tríades. O número de flores por inflorescência varia entre 5.904 - 17.316 para flores estaminadas e 180 - 3.528 para as flores pistiladas. Flores estaminadas com seis anteras e um feixe vascular cada; pistilódio trífido e vascularizado. Flores pistiladas com seis estaminódios unidos formando um círculo. Gineceu sincárpico, tricarpelar, trilocular, um óvulo por lóculo, sinascidiado no ovário e plicado acima. Estigma tripartido, apical e séssil, com epiderme composta por células papilosas alongadas, padrão de epiderme que se mantem por todo canal estilar. Óvulo é anátropo, paquicalazal e bitegumentado.

Germination and allometry of the native palm tree Euterpe edulis compared to the introduced E. oleracea and their hybrids in Atlantic rainforest / Germinação e alometria de Euterpe edulis comparadas à palmeira introduzida Euterpe oleracea e seus híbridos na floresta Atlântica

Palms are distinctive plants of tropics and have peculiar allometric relations. Understanding such relations is useful in the case of introduced species because their ability to establish and invade must be clarified in terms of their responses in the new site. Our purpose was to assess the survival and invasive capacity of an introduced palm species in the Atlantic rainforest, Euterpe oleracea Mart., compared to the native Euterpe edulis Mart. and to the hybrids produced between the two species. Considering this, we compared the allometry in different ontogenetic stages, the germination rates, and aspects of the initial development. The ontogenetic stages proposed for both Euterpe illustrated the growth patterns described for palm trees. E. oleracea and hybrids adjusted to the geometric similarity allometric model, while E. edulis presented a slope greater than would be expected considering this model, indicating a greater height for a given diameter. E. oleracea showed the same amount of pulp per fruit as E. edulis and a similar initial development of seedlings. The main differences observed were a lower germination rate and a faster height gain of E. oleracea seedlings. We conclude that E. oleracea, which is similar to E. edulis in aspects of allometry, development, seed and seedling morphology, may be an important competitor of this native palm tree in the Atlantic Forest.

Palmeiras são plantas características dos trópicos que apresentam relações alométricas peculiares. Compreender tais padrões pode ser útil no caso de espécies introduzidas, uma vez que sua habilidade de estabelecimento e invasão deve ser esclarecida em relação as suas respostas à nova localidade. Nosso propósito foi compreender a sobrevivência e a capacidade de invasão de uma palmeira introduzida na floresta Atlântica, Euterpe oleracea Mart. (açaizeiro) comparada à palmeira nativa Euterpe edulis Mart. (juçara), também considerando seus híbridos. Para isso comparamos suas relações alométricas em estádios ontogenéticos, sua germinação e seu desenvolvimento inicial. Os estádios ontogenéticos propostos para ambas as Euterpe ilustraram os padrões de crescimento esperados para palmeiras. E. oleracea e híbridos apresentaram-se sob o modelo alométrico de similaridade geométrica e E. edulis apresentou inclinação maior do que este modelo. E. oleracea produziu a mesma quantidade de polpa por fruto que E. edulis. As principais diferenças observadas foram menor taxa de germinação e maior velocidade de crescimento em altura para as plântulas de E. oleracea. Em conclusão, nossos resultados indicam que E. oleracea, sendo similar a E. edulis em termos de alometria, desenvolvimento e morfologia de sementes e plântulas, pode ser um importante competidor para a espécies nativa na Floresta Atlântica.

Stem anatomical characteristics of the climbing palm Desmoncus orthacanthos (Arecaceae) under two natural growth conditions in a tropical forest

Desmoncus orthacanthos is a Neotropical climbing palm that resembles rattan and therefore has similar potential applications. The genus Desmoncus (subfamily Arecoideae, subtribe Bactridinae) is distributed throughout the Americas, from veracruz, Mexico, to Brazil and Bolivia. The anatomical characteristics of its support tissue have not been thoroughly studied, although some observations from Central American artisans suggest that the stems collected from undisturbed sites possess better characteristics; these include a good capacity to withstand bending without breaking (i.e. higher fracture strength than plants from disturbed sites). Stem samples were collected from individuals from disturbed and undisturbed sites, at three points along the length of the stem (basal, medium and apical). Collections were made of one ramet from five individuals (n=5) at both sites. Each ramet was divided into three sections: basal, from soil surface to a height of 0.5 m; medium, from a height of 0.5 to 5.0 m; and apical, from a height 5.0 to 10.0 m. An anatomical analysis including vascular bundles, parenchyma elements and fibers was performed in the radial direction and also along the longitudinal direction of the stems. The amount of vascular bundles was greater for samples from undisturbed site stems; the amount of parenchyma cells differ between samples from both sites and the amount of fibers was greater for samples from disturbed site stems. The anatomical structural dimensions were smaller for samples from the undisturbed site stems. These findings partially confirm the artisans’ belief and supports the conclusion that microclimatic conditions affect plant anatomical structure. Rev. Biol. Trop. 56 (2): 937-949. Epub 2008 June 30.

Desmoncus orthacanthos es una palmera trepadora neotropical que puede, potencialmente, utilizarse en usos similares a los del ratán. El género Desmoncus (subfamilia Arecoideae, subtribu Bactridinae) se distribuye en América desde Veracruz, Mexico, hasta Brasil y Bolivia. Esta especie posee características anatómicas que no han sido ampliamente estudiadas pero observaciones hechas por artesanos centroamericanos sugieren que los tallos de sitios no perturbados por actividades humanas presentan mayor resistencia al doblado y menos tallos fracturados en el manejo. Las muestras de tallos fueron recolectadas de individuos que crecen en un sitio conservado y uno perturbado por actividades humanas, a tres alturas de la longitud del tallo (basal, media y apical). Se recolectó una rama de cada uno de cinco individuos (n=5) en ambos sitios. Cada rama fue dividida en tres secciones: basal, desde el nivel del suelo hasta los 0.5 m; medio, desde 0.5 a 5.0 m; y apical, desde 5.0 a 10.0 m. Se midió la cantidad por unidad de área y las dimensiones o tamaño (i.e. diámetro radial y diámetro perpendicular) de paquetes vasculares, células de parénquima y fibras. La cantidad de paquetes vasculares fue mayor en los tallos del sitio conservado, la cantidad de células de parénquima fue diferente entre sitios y la cantidad de fibras fue mayor en los tallos del sitio perturbado por actividades humanas. Estas características muestran cierta relación con los resultados mecánicos en otro estudio de los autores, los cuales confirman parcialmente las observaciones de los artesanos, lo que puede estar estrechamente relacionado con las características microclimáticas de los sitios de crecimiento.

Anatomía micrográfica del folíolo de la palma neotropical Bactris gasipaes (Arecaceae)

Leaf micrografic anatomy of the Neotropical palm Bactris gasipaes (Arecaceae). The economic importance of the palm Bactris gasipaes is growing in the Neotropoical region. We collected leaflets from plants under a chemical fertilization regime and a population of 5000 plants per hectare, in Costa Rica. The variety, Diamantes 10, has an ascendency fom the upper Amazon basin. We used Harries hematoxiline, eocine and standard light microscopy techniques. The presence of raphids and buliform cells was confirmed for the abaxial surface of the leaflets and for the hypodermic tissue on both sides. The absence of the Krantz anatomy was confirmed in consistence with former observations about the C3 photosynthesis in other species of Palmaceae. The average stomatal density on the abaxial surface was 96.87±16.31 stomata.mm-2 and 14.20±4.05 in the adaxial surface. Rev. Biol. Trop. 56 (2): 951-959. Epub 2008 June 30.

Se estudiaron hojas de plantas jóvenes cultivadas para producción de palmito de la variedad Diamantes 10 de ascendencia del Alto Amazonas. Se estudió la anatomía micrográfica foliar y la frecuencia de estomas en la superficie adaxial y abaxial de los foliolos de Bactris gasipaes provenientes de una plantación experimental en un régimen de fertilización química y una densidad de población de 5000 plantas por hectárea, en Guápiles, Costa Rica. Se confirmó la presencia de rafidios y células buliformes en la superficie abaxial de las láminas foliares y del tejido hipodermico en ambos lados. Confirmamos la ausencia de la anatomía Krantz en esta especie, reafirmando la fotosíntesis C3 como mecanismo metabólico en la familia Palmaceae. La densidad promedio de estomas en la superficie abaxial fue de 96,87±16,31 estomas.mm-2 y en la superficie adaxial fue de 14,20±4,05 estomas.mm-2.

Arborescent palm seed morphology and seedling distribution

Foi investigada a relação da morfologia das sementes de duas palmeiras arborescentes de grande porte, Attalea maripa (Aubl.) Mart. e Astrocaryum aculeatum G. Mey, com a chuva de sementes, em uma floresta amazônica sazonalmente seca. As sementes de A. maripa são menores e produzidas em maiores quantidades que aquelas de A. aculeatum. Tais sementes também têm uma quantidade de reservas nutricionais disponível para o embrião substancialmente menor. As plântulas de A. maripa foram encontradas em números muito maiores que as de A. aculeatum. Os resultados sugerem que, na escala espacial considerada, a chuva de sementes de A. maripa é mais restrita ao redor de palmeiras reprodutivas que aquela de A. aculeatum. As sementes de A. maripa, menores, devem ser menos atraentes para roedores que estocam seu alimento difusamente enterrando-o (e.g. Dasyprocta aguti). O padrão observado enfatiza a importância de tais roedores como dispersores de sementes de grande porte nas florestas neotropicais.