Physical-chemical, thermal, and functional properties of achira (Canna indica L.) flour and starch from different geographical origin

Achira (Canna indica L.) is a plant native to the Andes in South America, a starchy source, and its cultivation has expanded to different tropical countries, like Brazil. In order to evaluate the potential of this species, starch and flours with different particle size were obtained from Brazilian achira rhizomes. Proximal analyses, size distribution, SEM, swelling power, solubility, DSC, XRD analysis, and FTIR were performed for characterization of these materials. Flours showed high dietary fiber content (16.532.2% db) and high concentration of starch in the case of the smaller particle size fraction. Significant differences in protein and starch content, swelling power, solubility, and thermal properties were observed between the Brazilian and the Colombian starch. All the studied materials displayed the B-type XRD pattern with relative crystallinity of 20.1% for the flour and between 27.0 and 28.0% for the starches. Results showed that the starch and flour produced from achira rhizomes have great technological potential for use as functional ingredient in the food industry.

Piriformospora indica and Sebacina vermifera increase growth performance at the expense of herbivore resistance in Nicotiana attenuata

A Sebacinales species was recovered from a clone library made from a pooled rhizosphere sample of Nicotiana attenuata plants from 14 native populations. Axenic cultures of the related species, Piriformospora indica and Sebacina vermifera, were used to examine their effects on plant performance. Inoculation of N. attenuata seeds with either fungus species stimulated seed germination and increased growth and stalk elongation. S. vermifera inoculated plants flowered earlier, produced more flowers and matured more seed capsules than did non-inoculated plants. Jasmonate treatment during rosette-stage growth, which slows growth and elicits herbivore resistance traits, erased differences in vegetative, but not reproductive performance resulting from S. vermifera inoculation. Total nitrogen and phosphorous contents did not differ between inoculated and control plants, suggesting that the performance benefits of fungal inoculation did not result from improvements in nutritional status. Since the expression of trypsin proteinase inhibitors (TPI), defensive proteins which confer resistance to attack from Manduca sexta larvae, incur significant growth and fitness costs for the plant, we examined the effect of S. vermifera inoculation on herbivore resistance and TPI activity. After 10 days of feeding on S. vermifera-inoculated plants, larval mass was 46% higher and TPI activity was 48% lower than that on non-inoculated plants. These results suggest that Sebacina spp. may interfere with defense signaling and allow plants to increase growth rates at the expense of herbivore resistance mediated by TPIs.

Einiges über Vermehrung der Azalea indica

Von Kunstgärtner Grunert

Dinámica poblacional de planococcus ficus sign. (Hemiptera-Pseudcoccidae) en viñedos : Mendoza (Argentina)

Planococcus ficus Signoret es un insecto perteneciente al orden Hemiptera, familia Pseudococcidae, cuya población ha aumentado en los últimos años en Mendoza. Ataca gran variedad de hospederos y está distribuido en las principales zonas vitícolas del mundo. Su acción disminuye el vigor general de las plantas, perjudica la calidad de los frutos y las características organolépticas de los vinos elaborados con racimos infestados. El objetivo de este trabajo fue realizar estudios bioecológicos durante la temporada 2004-2005, analizando la forma de pasaje invernal y el número de generaciones anuales. Se marcaron y muestrearon plantas con los signos característicos del ataque. Se recolectó quincenalmente material vegetal infestado. En invierno: trozos de corteza. En primavera-verano: brotes, hojas y racimos. Los resultados indicaron que pasa el invierno principalmente como huevos agrupados en masas algodonosas, bajo la corteza. Se distinguieron seis generaciones, movilizándose conforme al aumento de las temperaturas hacia los brotes y hojas y, a partir de la tercera generación, a los racimos, permaneciendo en todas las partes aéreas de la planta el resto de la temporada hasta la caída de hojas. Con la disminución de las temperaturas retornó hacia la corteza del tronco para invernar.

Opuntia Sulphurea, un indicador de sobrepastoreo en matorrales de Larrea Divaricata : oeste de Mendoza (Argentina)

El presente estudio trató de demostrar cualitativa-cuantitativamente que Opuntia sulphurea es una especie indicadora de sobrepastoreo. Con este propósito fueron comparadas dos áreas: una levemente pastoreada con equinos y vacunos y la otra sobrepastoreada con caprinos, vacunos y equinos en una comunidad de Larrea divaricata en el Oeste de la provincia de Mendoza, Argentina. En ambas áreas fueron determinadas la cantidad de individuos de Opuntia sulphurea y el número total de los arbustos presentes. Fue elaborada una tabla en la cual las especies se ordenaron según grupos ecológicos. Fueron registrados el número, altura y tamaño de las plantas, número de cladodios (porción de vástago o rama comprimida y articulada) y números de cladodios vivos o muertos caídos por planta así como la cobertura total de Opuntia sulphurea. Para analizar la información fue usado un t-test (p < 0,05). Se comprobó que O. sulphurea aumentó su densidad de 1,3 plantas/100 m2 en el área levemente pastoreada a 15,9 plantas/100 m2 en la sobrepastoreada y este aumento fue favorecido por la propagación agámica a través de sus cladodios y facilitado por el ganado. Estos resultados son importantes para el manejo de los campos de pastoreo.

Palynological record and radiocarbon dates for sediment core T89-16, Congo River mouth

We present a high-resolution reconstruction of tropical palaeoenvironmental changes for the last deglacial transition (18 to 9 cal. kyr BP) based on integrated oceanic and terrestrial proxies from a Congo fan core. Pollen, grass cuticle, Pediastrum and dinoflagellate cyst fluxes, sedimentation rates and planktonic foraminiferal d18O ratios, uK37 sea-surface temperature and alkane/alkenone ratio data highlight a series of abrupt changes in Congo River palaeodischarge. A major discharge pulse is registered at around 13.0 cal. kyr BP which we attribute to latitudinal migration of the Intertropical Convergence Zone (ITCZ) during deglaciation. The data indicate abrupt and short-lived changes in the equatorial precipitation regime within a system of monsoonal dynamics forced by precessional cycles. The phases of enhanced Congo discharge stimulated river-induced upwelling and enhanced productivity in the adjacent ocean.

Ocean acidification alters the calcareous microstructure of the green macro-alga Halimeda opuntia

Decreases in seawater pH and carbonate saturation state (Omega) following the continuous increase in atmospheric CO2 represent a process termed ocean acidification, which is predicted to become a main threat to marine calcifiers in the near future. Segmented, tropical, marine green macro-algae of the genus Halimeda form a calcareous skeleton that involves biotically initiated and induced calcification processes influenced by cell physiology. As Halimeda is an important habitat provider and major carbonate sediment producer in tropical shallow areas, alterations of these processes due to ocean acidification may cause changes in the skeletal microstructure that have major consequences for the alga and its environment, but related knowledge is scarce. This study used scanning electron microscopy to examine changes of the CaCO3 segment microstructure of Halimedaopuntia specimens that had been exposed to artificially elevated seawater pCO2 of 650 µatm for 45 d. In spite of elevated seawater pCO2, the calcification of needles, located at the former utricle walls, was not reduced as frequent initiation of new needle-shaped crystals was observed. Abundance of the needles was 22 %/µm**2 higher and needle crystal dimensions 14 % longer. However, those needles were 42 % thinner compared with the control treatment. Moreover, lifetime cementation of the segments decreased under elevated seawater pCO2 due to a loss in micro-anhedral carbonate as indicated by significantly thinner calcified rims of central utricles (35-173 % compared with the control treatment). Decreased micro-anhedral carbonate suggests that seawater within the inter-utricular space becomes CaCO3 undersaturated (Omega < 1) during nighttime under conditions of elevated seawater pCO2, thereby favoring CaCO3 dissolution over micro-anhedral carbonate accretion. Less-cemented segments of H. opuntia may impair the environmental success of the alga, its carbonate sediment contribution, and the temporal storage of atmospheric CO2 within Halimeda-derived sediments.