Substrate, moisture, temperature and seed germination of the threatened endemic tree Eriotheca vargasii (Malvaceae) / Sustrato, humedad, temperatura y germinación de semillas del árbol endémico amenazado Eriotheca vargasii (Malvaceae)

Abstract We studied the germination of Eriotheca vargasii (Malvaceae), a poorly known endemic Peruvian Andean tree species characteristic of the dry forests of the Torobamba river valley, Peru. We determined seed characteristics, embryo morphology, viability, and assessed the influence of substrate (natural soil and commercially prepared media), temperature (controlled at 25 ºC and at ambient temperature between 18-22 ºC), and moisture (25 % and 50 % field capacity) on seed germination. Most seeds were ovoid in shape and although they contained well-developed embryos, only 46 % of them were viable. Substrate moisture levels had no influence on germination capacity or rate. In contrast, temperature and substrate type showed strong effects on germination. We observed the highest proportion of germinated seeds in prepared media at both temperatures tested (> 61 %). Furthermore, substrate types also influenced germination rates, with lower values in natural soil. The strongest effect on germination rates was by temperature, enhancing the difference in responses in substrate types (up to 90 % in commercially prepared media at 25 ºC). The low proportion of germinated seeds in soil (< 39 %), together with external local stress factors (e.g. grazing impact by herbivores), may be the critical factors contributing to the nearly total absence of seedlings and saplings of E. vargasiiin the study area despite abundant seed production. In order to ensure a supply of E. vargasii seedlings for reforestation efforts, we recommend producing E. vargasii plants in nurseries and conducting reforestation trials. We suggest that germination of seedlings is done following guidelines from this study. Rev. Biol. Trop. 66(3): 1162-1170. Epub 2018 September 01.

Resumen Estudiamos la germinación de Eriotheca vargasii (Malvaceae), un árbol endémico poco conocido de los andes peruanos y carácterístico de los bosques secos del valle del río Torobamba. Determinamos las características de la semilla, la morfología del embrión y la viabilidad; además evaluamos la influencia del sustrato (suelo y sustrato preparado comercialmente), temperatura (controlada a 25 ºC y sin control entre 18-22 ºC) y humedad (25 % y 50 % de capacidad de campo) sobre la germinación de las semillas. La mayoría de las semillas tuvo forma ovoide y aunque la mayoría contenía embriones bien desarrollados, sólo el 46 % de estas fue viable. Los niveles de humedad del sustrato no tuvieron influencia sobre la capacidad o tasa de germinación, mientras que la temperatura y el tipo de sustrato si tuvieron efectos visibles. Observamos las proporciones más altas de semillas germinadas en los sustratos preparados y en ambas temperaturas (> 61 %). Adicionalmente, el tipo de sustrato también influenció las tasas de germinación, con valores más bajos en el suelo natural. El efecto más fuerte sobre las tasas de germinación se dió por la temperatura, aumentando las diferencias de las respuestas de acuerdo al tipo de sustrato (hasta un 90 % de germinación en sustratos preparados comercialmente y a 25 ºC). La baja proporción de semillas germinadas en el suelo (< 39 %), junto con factores locales de estrés externos (como por ejemplo el impacto por herbivoría), pueden ser elementos clave que están contribuyendo a la casi ausencia total de plántulas de E. vargasii en el área de estudio, a pesar de una producción de semilla abundante. Para asegurar proveer plantones de E. Vargasii para esfuerzos de reforestación, recomendamos producir plantas de esta especie en viveros y realizar experimentos de reforestación. Sugerimos que la germinación de las plántulas se haga siguiendo las recomendaciones de este estudio.

Morfología de semillas y desarrollo post-seminal de especies de Comanthera (Eriocaulaceae)

Comanthera brasiliana, C. magnifica y C. suberosa (Eriocaulaceae) forman parte de la lista de especies amenazadas de extinción en Brasil, debido a su alto grado de endemismo y a la recolecta indiscriminada. Estas tres especies junto con C. brunnea y C. linearis constituyen el clado de Comanthera magnifica. Se estudió la germinación, la morfología de semillas y el desarrollo post-seminal de las cinco especies, buscando caracterizar morfológica y anatómicamente las semillas y estadios posteriores a la germinación, así como generar datos que ayuden en la conservación de estas especies. Se recolectaron semillas maduras en los "campos rupestres" de Minas Gerais, Brasil. Fueron puestas a germinar cuatro repeticiones de 15 semillas para cada especie en cajas de Petri con papel filtro humedecido con agua destilada, a 25 °C y luz fluorescente. Para el estudio morfológico de las semillas fue usado microscopía electrónica de barrido. Para la anatomía del desarrollo post-seminal, cada estado del desarrollo fue incluido en historresina, cortado con un micrótomo rotativo y analizado con microscopía de luz. Forma y tamaño de las semillas, así como las estructuras de la cubierta seminal permiten diferenciar las especies; a partir de estos caracteres desarrollamos una clave de identificación. Las semillas germinan en altos porcentajes (> 90 %) y rápidamente (< 7 días). La germinación ocurre a través de la protrusión del eje embrionario. Aproximadamente cuatro días después de germinar aparece la primera hoja, seguida por la raíz adventicia; después de 10-15 días se desarrollan la segunda hoja y nuevas raíces adventicias. En condiciones naturales estas especies habitan en suelos derivados de cuarcita y poseen semillas diminutas (tipo polvo) que germinan y se desarrollan rápidamente, incluso más rápido que en otras Eriocaulaceae de suelos mésicos. Estos datos pueden ayudar en la obtención de plántulas de las especies estudiadas, contribuyendo en la conservación de las mismas.

Comanthera brasiliana, C. magnifica and C. suberosa (Eriocaulaceae) are included in the Brazilian list of endangered species, due to intensive harvest and micro-endemism. These species form the clade of Comanthera magnifica, along with C. brunnea and C. linearis. Germination, seed morphology and post-seminal development were studied aiming to characterize all five species and to provide information for their conservation. Seeds were collected in "campos rupestres" of Minas Gerais, Brazil. Seed morphology was examined using scanning electron microscope. For germination tests, mature seeds were placed in Petri dishes lined with filter paper dampened with distilled water at 25 °C and fluorescent light; four repetitions with 15 seeds were performed for each species. For the anatomical analysis of post-seminal development, seedlings at different developmental stages were included in historesin, cut with a rotatory microtome and examined under a light microscope. The structure of the seed coat and the shape and size of the seeds were characteristics that allowed species differentiation, and based on the seeds morphological characteristics, an identification key is provided. The seed germination was high (> 90 %) and fast (< 7 days). Germination occured through the axis protrusion of the embryo. Approximately four days after germination, the first leaf develops and is followed by the adventitious roots. After 10-15 days, the second leaf and the new adventitious roots develop. In field conditions, the studied species occur in quartzite soils and their small seeds (dust-like type) germinate faster than the other Eriocaulaceae species (from mesic soils). These results provide reliable information that may contribute to the species management and conservation.

Seed Morphology and Protein Patterns (SDSPAGE) as a Mean in Classification of Some Taxa of the Subfamily Mimosoideae (Fabaceae).

Aims: This study is developed to discuss whether the plant morphology and seed characters (macro and micromorphological and protein pattern) can provide an additional fundamental tool helping in explanation of the taxonomic trends at specific and infraspecific level within the 47 studied taxa belonging to subfamily Mimosoideae (Fabaceae) and to compare the proposed taxonomic treatment based on numerical analysis (dendrogram) with other previous and current systems of classification. Methodology: The macro and micromorphological characters of the whole plant and seed as well as seed protein pattern of 47 taxa of subfamily Mimosoideae, family Fabaceae were investigated (using LM, SEM and Stereomicroscope and SDS-PAGE technique respectively). The taxa under investigation represent three tribes, seven genera and 46 species including three subspecies. The macro and micromorphological criteria (219 attributes) and seed protein pattern attributes (38 bands) extracted were numerically analyzed using NTsys-Pc program (version 2.02). Results: The taxonomic treatment of the Mimosoideae taxa under investigation were based on the numerical analysis of 257 macro-, micromorphology of whole plant and seed protein attributes. The dendrogram interprets the similarities and dissimilarities between the investigated taxa. The dendrogram revealed that the taxa under investigation were split into two main series and 25 groups. The splitting Series I includes 12 groups which represented by 20 of the studied Acacia species. Series II includes 13 groups which represented by 15 sp. of Acacia and the species of other six studied genera, group 17 as well as group 21 contain species from different genera. The specific and infra-specific relationships were discussed and compared with some current systems of classification. Conclusion: There is no difference of opinion about the phyletic position of the Acacieae which is always considered a link between Mimoseae and Ingeae. However different affinities of the genus Acacia taken as a natural unit have been suggested. The tribe Mimoseae represents the polymorphic and older core of Mimosoideae.

Taxonomic relationships in some Vicia species from Egypt, based on seed morphology and SDS-PAGE of seed proteins / As relações taxonômicas das espécies Vicia oriundas do Egito, baseadas na morfologia da semente e na SDS-PAGE das proteínas da semente

The seed morphology and seed proteins of 11 Vicia taxa from Egypt were studied. Macro-and micro-morphological characters, including seed shape, color, size, hilum shape and seed sculpture were described and analyzed. The secondary sculpture of the cell wall varies from papillose in nearly all Vicia species to lophate in V. hirsuta. Further, the seed proteins of studied taxa were investigated by SDS-PAGE and 39 different bands were scored. The similarity analysis based on the SDS-PAGE profile and seed morphology was found to be a useful characteristic for the discrimination of Vicia species both on the subgeneric and the sectional levels. The present study did not acknowledge V. tetrasperma and V. hirsuta as subgenus Ervum. As a result, division of Vicia into two subgenera i.e. Vicia and Cracca, is supported.

Analisam-se a morfologia e as proteínas de sementes de 11 táxons de Vicia oriundos do Egito. As características macro- e micro-morfológicas, como forma da semente, cor, tamanho, forma do hilo e a escultura da semente são descritas e analisadas. A escultura secundaria da parede celular varia na papilose em quase todas as espécies de Vicia até a lofada em V. hirsuta . As proteínas das sementes dos táxons foram analisadas por SDS-PAGE onde 39 bandas diferentes foram detectadas. A análise de similaridade baseada no perfil de SDS-PAGE e na morfologia da semente foi uma característica útil para discriminar as espécies de Vicia em níveis subgenérico e seccional. Essa investigação rejeitou V. tetrasperma e V. hirsuta como subgênero de Ervum, mas aceitou a divisão de Vicia em dois subgêneros, ou seja, Vicia e Cracca.