RESUMO
BACKGROUND AND AIMS: Like other clades, the Coffea genus is highly diversified on the island of Madagascar. The 66 endemic species have colonized various environments and consequently exhibit a wide diversity of morphological, functional and phenological features and reproductive strategies. The trends of interspecific trait variation, which stems from interactions between genetically defined species and their environment, still needed to be addressed for Malagasy coffee trees. METHODS: Data acquisition was done in the most comprehensive ex situ collection of Madagascan wild Coffea. The structure of endemic wild coffees maintained in an ex situ collection was explored in terms of morphological, phenological and functional traits. The environmental (natural habitat) effect was assessed on traits in species from distinct natural habitats. Phylogenetic signal (Pagel's λ, Blomberg's K) was used to quantify trait proximities among species according to their phylogenetic relatedness. KEY RESULTS: Despite the lack of environmental difference in the ex situ collection, widely diverging phenotypes were observed. Phylogenetic signal was found to vary greatly across and even within trait categories. The highest values were exhibited by the ratio of internode mass to leaf mass, the length of the maturation phase and leaf dry matter content (ratio of dry leaf mass to fresh leaf mass). By contrast, traits weakly linked to phylogeny were either constrained by the original natural environment (leaf size) or under selective pressures (phenological traits). CONCLUSIONS: This study gives insight into complex patterns of trait variability found in an ex situ collection, and underlines the opportunities offered by living ex situ collections for research characterizing phenotypic variation.
Assuntos
Café , Folhas de Planta , Ilhas , Madagáscar , Fenótipo , FilogeniaRESUMO
A novel structure of nonautonomous long terminal repeat (LTR) retrotransposons called terminal repeat with GAG domain (TR-GAG) has been described in plants, both in monocotyledonous, dicotyledonous and basal angiosperm genomes. TR-GAGs are relatively short elements in length (<4 kb) showing the typical features of LTR-retrotransposons. However, they carry only one open reading frame coding for the GAG precursor protein involved for instance in transposition, the assembly, and the packaging of the element into the virus-like particle. GAG precursors show similarities with both Copia and Gypsy GAG proteins, suggesting evolutionary relationships of TR-GAG elements with both families. Despite the lack of the enzymatic machinery required for their mobility, strong evidences suggest that TR-GAGs are still active. TR-GAGs represent ubiquitous nonautonomous structures that could be involved in the molecular diversities of plant genomes.
Assuntos
Coffea/genética , Genoma de Planta , Retroelementos/genética , Sequências Repetidas Terminais/genética , Algoritmos , Sequência de Bases , Sequência Conservada/genética , Dosagem de Genes , Cadeias de Markov , Anotação de Sequência Molecular , Dados de Sequência Molecular , Família Multigênica , Transcrição GênicaRESUMO
La propagación de material de ñame de buena calidad es esencial para incrementar la producción sostenible de este cultivo. El presente trabajo tuvo como propósito optimizar el medio de cultivo de micropropagación de Dioscorea alata L. clon Caraqueño a través de los siguientes objetivos: determinar el efecto de diferentes antioxidantes (carbón activado 0,5 g/L-1 ; carbón activado 1,0 g/L-1; cisteína 10 mg/L-1, 20 mg/L-1 y 30 mg/L-1) y concentraciones de sales de Murashige y Skoog (MS) (25, 50, 75 y 100 %) en el medio de cultivo durante el establecimiento y la multiplicación de las plantas in vitro, y evaluar la utilización de distintas combinaciones de ácido naftalenacético (0,01; 0,1 mg/L-1) y bencilaminopurina (0,01; 0,1 mg/L-1) en el mejor medio de cultivo de multiplicación obtenido en el experimento anterior. A los 35 días se seleccionaron 40 plantas in vitro, a las cuales se les determinaron las siguientes variables: longitud en cm del vástago; número de nudos de novo por explantes; número de hojas por explante y porcentaje de fenolización. Se evaluó además, en el experimento con los reguladores de crecimiento, el número de raíces y longitud de la raíz de mayor tamaño. Se aplicó un diseño experimental completamente aleatorio con análisis de varianza bifactorial y clasificación simple. Se realizó la prueba de comparación de medias de Tukey para un nivel de significación del 5%. Los resultados obtenidos mostraron que las sales MS al 75% de su concentración, el carbón activado (0,5 g/L-1) o la cisteína (10 mg/L-1), en combinación con los reguladores de crecimiento ANA/BAP (0,01/0,01 mg/L-1) en el medio de cultivo MS, incrementaron los indicadores de desarrollo de las plantas in vitro tales como número de nudos de novo (3,5), longitud del vástago (4,1 cm), número de hojas (3,8), número de raíces (5,7) y longitud de las raíces (6 cm).
The material propagation of good quality yam is essential to increase the sustainable production of this cultivation. In the present work the optimization of culture medium of Dioscorea alata L. clone Caraqueño micropropagation was carried out through the following objectives: to determine the effect of different anti-oxydants (activated charcoal 0,5 g.L-1; activated charcoal 1,0 g.L-1; cysteine 10 mg.L-1, 20 mg.L-1 and 30 mg.L-1) and Murashige and Skoog salts concentrations (25, 50, 75 and 100%) in the culture medium during the in vitro plants establishment and the multiplication, and to evaluate the use of different combinations of naftalenacetic acid (0,01; 0,1 mg.L-1) and benzylaminopurine (0,01; 0,1 mg.L-1) in the best multiplication medium obtained in the above experiment. At 35 days, 40 in vitro plants were selected. The following variables were determined in these plants: shoot length, cm; leaf and bud explant number; and oxydation phenolic percentage. In the experiment of plant growth regulators was also evaluated, the roots number and greater size root length. A totally randomized experimental design with one and two factor variance analysis and the Tukey test for means comparison at 5% significance level were applied. The obtained results showed that the salts MS at 75% concentration, the activated charcoal (0,5 g. L-1) or the cysteine (10 mg. L-1), in combination with the growth regulators ANA/BAP (0,01/0,01 mg.L-1) in the MS culture medium, increase the development of the in vitro plants, number of novo buds (3,5), shoot length (4,1 cm), number of leaves (3,8), number of roots (5,7) and greater size root length (6 cm).