Physiological potential of jenipapo seeds stored in different packages / Potencial fisiológico de sementes de jenipapo armazenadas em diferentes embalagens

Seed storage through the reduction of its water content is an important strategy for the conservation of many plant species, but some, such as the jenipapo, are susceptible to desiccation, which may lead to loss of viability and even death, in case its water content is reduced to a critical level. The aim of this work was to evaluate the interference of different packaging conditions in the conservation of the physiological potential of jenipapo seeds stored for 105 days. Specifically, this research sought to analyze the feasibility of the use of vacuum conditions and the coating of the seed with biofilm. The evaluated treatments were: storage in paper bag, plastic bag, plastic with vacuum, plastic with seeds coated with biofilm and plastic with seeds with biofilm and vacuum condition for 15, 45, 75 and 105 days, besides the control. Seeds with biofilm were treated with cassava starch at 3% of the mass to volume ratio. The following tests were performed: water content, germination, germination speed, aerial part and root lengths, wet and dry mass of the aerial part and root. It was concluded that plastic packaging, vacuum condition and biofilm coating are not recommended for storage of jenipapo seeds. Storage in paper bags, when at 24 ºC and with 65% relative humidity for 46 days, is capable of conserving the seeds of jenipapo with germination of 60%.

O armazenamento de sementes por meio da redução do seu teor de água é uma importante estratégia para a conservação de muitas espécies vegetais, porém, algumas, como o jenipapeiro, são sensíveis à dessecação, podendo haver a perda da sua viabilidade, e até a morte, caso o seu teor de água seja reduzido a um nível considerado crítico. Neste trabalho, o objetivo foi avaliar a interferência de diferentes condições de embalagens na conservação do potencial fisiológico de sementes de jenipapo armazenadas por 105 dias. De forma específica, buscou-se analisar a viabilidade do uso de condições de vácuo e do revestimento da semente com biofilme. Os tratamentos avaliados foram: armazenamento em saco de papel, saco plástico, plástico com vácuo, plástico com sementes revestidas com biofilme e plástico com sementes com biofilme e condição de vácuo por 15, 45, 75 e 105 dias, além da testemunha. As sementes com biofilme receberam tratamento com fécula de mandioca a 3% da relação massa por volume. Os seguintes testes foram realizados: teor de água, germinação, velocidade de germinação, comprimento da parte aérea e radicular, massa úmida e seca da parte aérea e da raiz. Concluiu-se que a embalagem plástica, a condição de vácuo e o revestimento com biofilme não são recomendados para o armazenamento de sementes de jenipapo. O armazenamento em saco de papel quando realizado em ambiente com 24 ºC e 65% de umidade relativa do ar durante 46 dias é capaz de conservar as sementes de jenipapo com germinação de 60%.

Morphology, ecophysiology and germination of seeds of the Neotropical tree Alibertia patinoi (Rubiaceae) / Morfología, ecofisiología y germinación de semillas del árbol neotropical

Alibertia patinoi (Rubiaceae). Alibertia patinoi (Rubiaceae) is of economic and cultural importance for communities in the Colombian Pacific and Amazon regions, where it is cultivated and mature fruits are highly appreciated and consumed. Since there is a lack of knowledge of the seed physiology of this species, we describe here the germination behavior and morphometry of seeds of Alibertia patinoi, and relate them to its habitat. Fruits were collected from a mixed food crop and a commercial plantation in Guaimía village, Buenaventura, Colombia, a tropical rain forest area. We measured length, width, thickness, mass (n=1 400), and moisture content of seeds (n=252). Primary dormancy tests were conducted (n=200), followed by imbibition (n=252) and germination dynamics, under different conditions of light and temperature specific to understory and forest clearings (n=300 seeds). Finally, seed storage behavior was established (n=100 seeds). We observed that size and mass of seeds had a narrow range of values that did not differ within or among fruits and that the species did not exhibit primary dormancy. The seeds are recalcitrant, and recently harvested seeds exhibited higher seed moisture content (ca. 44%) and continuous metabolism. The seed germination percentage was observed to be higher under the specific dense canopy forest light and temperature conditions; furthermore, neither enriched far-red light nor darkness conditions inhibited germination. We concluded that rapid germination could be the establishment strategy of this species. Also, the physiological traits (i.e., rapid germination rate, low germination requirements, absence of primary dormancy, and recalcitrant behavior) and seed size and mass, suggest that A. patinoi is adapted to conditions of mature tropical rain forests.

La germinación y morfometría de las semillas de Alibertia patinoi se describen y se relacionan con el hábitat de la especie, el Bosque Pluvial Tropical Americano. Se midió la longitud, ancho, grosor, peso y contenido de humedad de las semillas. Se realizaron pruebas de latencia, imbibición y dinámica de la germinación con diferentes condiciones de luz y temperatura específicas de claros y de sotobosque cubierto por un dosel denso. Además, se estableció el comportamiento de almacenamiento de las semillas. El tamaño y peso de las semillas no difieren dentro ni entre frutos. Las semillas recién cosechadas no tienen latencia primaria, presentan alto contenido de humedad (ca. 44%), metabolismo continuo y son recalcitrantes. La germinación tuvo porcentajes altos y en condiciones de luz y temperatura específicas de bosque con follaje denso, y ni la luz enriquecida con rojo lejano ni la oscuridad inhibieron la germinación. Se concluye que la germinación rápida podría ser la estrategia de establecimiento de esta especie. Además, los rasgos fisiológicos, el tamaño y peso de las semillas, sugieren que A. patinoi está adaptada a las condiciones del bosque lluvioso tropical maduro y se comporta como una especie que no es pionera.

Cultivo de tejidos de Piper sp. (Piperaceae): Propagación, organogénesis y conservación de germoplasma in vitro / Tissue culture of Piper sp. (Piperaceae): in vitro propagation, organogenesis and germplasm conservation

En el Nuevo Mundo el género iPiper (Piperaceae) comprende al menos 500 especies en las que muchos compuestos biológicamente activos fueron identificados; es por ello que el estudio sobre la química y biosíntesis de los miembros de este género son de gran interés, donde el cultivo de tejidos in vitro juega un rol fundamental. El propósito de este trabajo fue desarrollar varios sistemas de cultivo in vitro, en diferentes especies de Piper, con la finalidad de propagarlas clonalmente y regenerarlas por organogénesis directa para el establecimiento de plantas en campo, y la conservación y transferencia internacional de germoplasma. La germinación de semillas alcanzó aproximadamente entre el 20 y el 99% después de 4 semanas de cultivo. La micropropagación fue realizada en medio de cultivo MS suplementado con sacarosa 3%, AIA 0,02 mg L-1 y AG3 0,02 mg L-1. El potencial morfogenético de explantes de raíz, peciolo, hoja, nudo y entrenudo fue investigado con la finalidad de desarrollar un protocolo confiable de regeneración de plantas. La conservación e intercambio internacional de germoplasma in vitro también fue realizado, entre Perú, Brasil y Ecuador.

In the New World the genus Piper (Piperaceae) contains at least 500 species in which many biologically active compounds were identified; is why the study of the chemistry and biosynthesis in members of this genus are of interest, and here techniques in vitro tissue culture plays a fundamental role. The aim of this work was to establish several in vitro culture systems in different Piper species in order to propagate clonally and regenerate by direct organogenesis for the establishment the field plants, the conservation and international germoplasm exchange. The seed germination achieved approximately 20 - 99% after 4 weeks of culture. The micropropagation was performed on MS culture medium supplemented with sucrose (3%), IAA (0,02 mg L-1) and GA3 (0,02 mg L-1). Callus induction and morphogenetic potential of root, petiole, leaf, node and internode explants was investigated to develop a reliable plant regeneration protocol. The in vitro germplasm conservation and international germplasm exchange also was realized, between Perú, Brazil and Ecuador.

Germination and soil seed bank traits of Podocarpus angustifolius (Podocarpaceae): an endemic tree species from Cuban rain forests

Podocarpus angustifolius is an endangered recalcitrant-seeded small tree, endemic to mountain rain forests in the central and Pinar del Río regions in Cuba. In this study, the germination patterns of P. angustifolius seeds were evaluated and the nature of the soil seed bank was determined. Using a weighted two-factor design, we analyzed the combined germination response to seed source (i.e. freshly matured seeds directly collected from trees versus seeds extracted from soil samples) and pretreatment (i.e. seed water-immersion for 48h at room temperature). Germination was delayed for four weeks (≈30 days) in all cases, regardless of both factors analyzed. Moreover, nine additional days were necessary to achieve high germination values (in the case of fresh, pretreated seeds). These results overall may indicate the existence of a non-deep simple morphophysiological dormancy in P. angustifolius seeds. The water-immersion significantly enhanced seed germination, probably as a result of the hydration of recalcitrant seeds. Although germination of seeds extracted from soil samples was low, probably due to aging and pathogen effects throughout the time of burial, the study revealed the existence of a persistent soil seed bank (at least short-termed) of ≈42 viable seeds per m² in the upper 10cm of soil. Such a record is noteworthy since references to persistent soil seed banks in recalcitrant-seeded species are scarce in the literature. The population consequences derived from the formation of persistent soil seed banks in this endangered species are discussed. Rev. Biol. Trop. 59 (3): 1061-1069. Epub 2011 September 01.

Podocarpus angustifolius es un árbol endémico de los bosques lluviosos de la región de Pinar del Río y la parte central de Cuba, que se encuentra en peligro de extinción. En este estudio se evaluó la germinación de sus semillas y la naturaleza del banco de semillas del suelo. Específicamente, se analizó la respuesta germinativa de las semillas a dos factores: su procedencia (recolectadas directamente de los árboles versus extraídas de muestras de suelo) y el pretratamiento (inmersión en agua durante 48h a temperatura ambiente). La germinación no comenzó hasta las cuatro semanas (≈30 días) en todos los casos. Además, fueron necesarios 9 días más para alcanzar un valor elevado de germinación (en el caso de semillas recolectadas del árbol con pretratamiento), lo que parece indicar la existencia de un letargo de tipo morfofisiológico simple no profundo. El pretratamiento incrementó significativamente la germinación, posiblemente por hidratación de las semillas recalcitrantes. El estudio demostró la existencia de un banco de semillas persistente en el suelo, al menos de corta duración de ≈42 semillas viables por m² en los 10 primeros cm del suelo. Dicho hallazgo es destacable, ya que los casos descritos en la literatura sobre bancos persistentes en especies con semillas recalcitrantes son escasos. Además, se discute la importancia que tiene para esta especie amenazada la existencia de un banco de semillas persistente.

MÉTODOS SIMPLES DE ARMAZENAMENTO DAS SEMENTES DE ANDIROBA (Carapa guianensisAubl. e Carapa proceraD.C. -Meliaceae)

It was intended to test several simple storage methods, which could be wildly used to conserve recalcitrant seeds of forest trees, whose reforestation is limited by the shortage of its seeds. Carapa procerae C. guianensisare tropical trees of economic interest, its seeds loose viability few days after collection. It was already shown, that for C. procera this loss of viability is correlated with the moisture content of the seeds. The storage of the seeds in plastic bags were studied during 7 months under different environmental conditions and in water. The moisture content of the seeds was observed before and after the storage. Storage under external conditions was not successful, probably because the plastic bags were destroyed by insects which caused dehydration of the seeds, or hydration of those stored in the soil, which then consequently started to germinate. Storage under current water was not possible; neither storage at low temperature (6 °C +/- 4 °C). It was possible to maintain the viability of the seeds in sealed plastic bags under air conditioning (25°C +/- 4 °C and 45 - 60% r. H.) during 7 months.

O estudo objetivou testar procedimentos simples e de ampla aplicação que permitem o armazenamento de sementes recalcitrantes de essências florestais cuja produção de mudas é limitada pela oferta de sementes. Carapa procerae C. guianensissão espécies de interesse econômico cujas sementes perdem sua capacidade germinativa poucos dias após a coleta. Em C. proceratal perda já foi correlacionada com a desidratação das sementes. Foram testados métodos de armazenamento em sacos plásticos, durante 7 meses, em diferentes condições ambientais e em água corrente. Observou-se os teores de umidade no inicio e após os tratamentos. O armazenamento na sombra não teve sucesso, provavelmente devido a destruição da embalagem por insetos, o que causou a perda da viabilidade das sementes por dessecamento. O armazenamento das sementes enterradas no solo também não foi possível, devido a destruição dos sacos pela fauna do solo, o que favoreceu a embebição e consequentemente a germinação das sementes. Sementes de andiroba não suportaram o armazenamento em água corrente e nem em condições de temperaturas baixas (6 °C +/- 4 °C). O armazenamento mostrou manter a viabilidade das sementes em sacos plásticos selados, quando realizado em ambientes com ar-condicionado (25 °C +/- 4 °C e 45 - 60 % de umidade relativa) durante 7 meses.