Composición química de Apodanthera biflora, una cucurbitácea del bosque seco del noroeste peruano

The dry forest of northwestern Peru is the habitat of numerous native species that have received little attention beyond taxonomic purposes. Here we report the chemical composition of the roots and seeds of a set of accessions of Apondanthera biflora, a wild Cucurbit with potentialities as a food resource. The roots show features that are comparable to those from cassava roots and potato tubers: a high content of carbohydrates on a dry matter basis (77.5 – 84.9%), with starch representing around 20% of the total dry matter. The seeds’ fat content on a dry matter basis (22.22 – 39.37%) falls within the percentages found in oily seeds such as safflower, whereas the protein content (21.37 – 29.06%) is similar to that of flax and sunflower. The fatty acid profile of the seed’s oil shows a predominance of polyunsaturated acids, in particular linoleic acid (43.81%), making it comparable to that of cotton oil. Our results confirm the nutritional value of Apodanthera biflora and set the ground for its use in domestication and food security programs.han sido poco estudiadas. En este trabajo se reporta la composición química de las raíces y semillas de un grupo de accesiones de Apodanthera biflora, una cucurbitácea silvestre con potencial nutricional. Las raíces muestran una composición comparable a la de la yuca y la papa: un alto contenido de carbohidratos en base al peso seco (77,5 - 84,9%), entre los cuales destaca el almidón con alrededor de 20% del peso seco. El contenido de grasas de la semilla en base al peso seco (22,22 - 39,37%) está dentro del rango descrito en semillas oleaginosas como las de cártamo, mientras que el contenido de proteínas (21,37 - 29,06%) es similar al hallado en semillas de lino y girasol. En el perfil de ácidos grasos del aceite de la semilla se observa un predominio de los ácidos grasos poliinsaturados, en particular del ácido linoleico (43,81%), que lo hace comparable al del aceite de algodón. Los resultados confirman el valor nutricional de Apodanthera biflora y sienta las bases para su domesticación y aprovechamiento en programas de seguridad alimentaria

Community Impacts of Prosopis Juliflora Invasion: Biogeographic and Congeneric Comparisons

We coordinated biogeographical comparisons of the impacts of an exotic invasive tree in its native and non-native ranges with a congeneric comparison in the non-native range. Prosopis juliflora is taxonomically complicated and with P. pallida forms the P. juliflora complex. Thus we sampled P. juliflora in its native Venezuela, and also located two field sites in Peru, the native range of Prosopis pallida. Canopies of Prosopis juliflora, a native of the New World but an invader in many other regions, had facilitative effects on the diversity of other species in its native Venezuela, and P. pallida had both negative and positive effects depending on the year, (overall neutral effects) in its native Peru. However, in India and Hawaii, USA, where P. juliflora is an aggressive invader, canopy effects were consistently and strongly negative on species richness. Prosopis cineraria, a native to India, had much weaker effects on species richness in India than P. juliflora. We carried out multiple congeneric comparisons between P. juliflora and P. cineraria, and found that soil from the rhizosphere of P. juliflora had higher extractable phosphorus, soluble salts and total phenolics than P. cineraria rhizosphere soils. Experimentally applied P. juliflora litter caused far greater mortality of native Indian species than litter from P. cineraria. Prosopis juliflora leaf leachate had neutral to negative effects on root growth of three common crop species of north-west India whereas P. cineraria leaf leachate had positive effects. Prosopis juliflora leaf leachate also had higher concentrations of total phenolics and L-tryptophan than P. cineraria, suggesting a potential allelopathic mechanism for the congeneric differences. Our results also suggest the possibility of regional evolutionary trajectories among competitors and that recent mixing of species from different trajectories has the potential to disrupt evolved interactions among native species

Evaluation of induced responses, insect population growth, and host-plant fitness may change the outcome of tests of the preference-performance hypothesis: A case study

The preference-performance hypothesis predicts that insect preference should correspond to host suitability for offspring development. We studied the pattern of within-plant preference in the aphid Sipha flava and its consequences for offspring performance on the host-plant Sorghum halepense, regarding the role of induced responses of plants to aphid feeding. The consequences of within-plant preference on aphid population growth and host-plant traits were also evaluated. Our results showed that winged and wingless aphids preferred to settle on mature rather than young leaves. In contrast, aphid individual growth rate was higher on young leaves when compared with mature leaves, suggesting that the outcome of this test rejected the preference-performance hypothesis. However, the inclusion of the factor 'previous aphid infestation' changed the outcome from a maladaptive choice to a neutral one. Thus, individual growth rates of S. flava increased when aphids developed on leaves that had b

Galler-induced reduction of shoot growth and fruit production in the shrub Colliguaja integerrima (Euphorbiaceae) Insectos cecidómidos reducen el crecimiento de brotes y la producción de frutos en el arbusto Colliguaja integerrima (Euphorbiaceae)

We evaluated experimentally the effect of a gall-maker insect on vegetative and reproductive traits of the shrub Colliguaja integerrima (Euphorbiaceae). We performed two experiments: (1) a chemical (insecticide) exclusion to prevent gall formation, and (2) a mechanical removal of new galls at the early stage to prevent gall growth. In the study area, galled shrubs were common (77 %). Because the pattern of insect attack may influence plant fitness, the distribution of egg clusters deposited by the galler and the number of galls among shrubs were also evaluated. Fruit production was inversely associated with the number of galls, but did not correlate with shrub height, shrub cover, and number of shoots. Ungalled shoots were longer than galled shoots after 12 months initiated the experiment. Chemical exclusion produced a delayed positive effect on plant reproduction. Fruit production was higher in experimental than control branches after 24 months. Mechanical removal of galls increased fruit production in comparison to control branches in the next reproductive season. These results indicate that the galler reduces shoot growth, and has a delayed detrimental impact on fruit production of C. integerrima. Because the chance of finding new galls was higher on the previously infected shrubs, it is possible that reinfection processes account for the cumulative negative effects of the bud-galling insect on plant fitnessEvaluamos experimentalmente el efecto de un insecto cecidómido sobre rasgos vegetativos y reproductivos del arbusto Colliguaja integerrima (Euphorbiaceae). Efectuamos dos experimentos: (1) una exclusión química (insecticida) para impedir la formación de cecidias, y (2) una remoción mecánica de cecidias recién formadas para evitar su crecimiento. En el sitio de estudio, los arbustos con cecidias fueron comunes (77 %). Como el patrón de ataque del insecto puede influir en el desempeño de la planta, evaluamos también la distribución de huevos depositados por el cecidómido y el número de cecidias entre arbustos. La producción de frutos se relacionó inversamente con el número de cecidias, pero no presentó asociación significativa con la altura del arbusto, su cobertura ni con el número de brotes. Brotes sin cecidias fueron más largos que los con cecidias. El tratamiento químico produjo un efecto positivo retrasado sobre la reproducción de la planta. Una vez transcurridos 24 meses de iniciado el experimento químico, el número de frutos fue mayor en las ramas experimentales que en las ramas control (con cecidias). De igual manera, la remoción mecánica de cecidias aumentó la producción de frutos en comparación a las ramas control en la siguiente estación reproductiva del arbusto. Estos resultados indican que el cecidómido reduce el crecimiento de los brotes y tiene un efecto negativo retardado sobre la producción de frutos de C. integerrima. Como la probabilidad de detectar cecidias nuevas fue mayor en los arbustos previamente infectados, es posible que el proceso de reinfección de cuenta de los efectos negativos acumulativos del insecto sobre el desempeño de la plant

Outcrossing increases infection success in the holoparasitic mistletoe Tristerix aphyllus (Loranthaceae)

Most studies on the fitness advantage of outbreeding in host-parasite systems have been assessed from the host rather than the parasite perspective. Here, we performed experimental pollination treatments to evaluate the consequences of outbreeding on fitness-related traits in the holoparasitic mistletoe Tristerix aphyllus in a 2-year field study. Results indicate that self-pollinated plants had a lower fruit production than outcrossed plants (20.4% and 29.5% reduction in 2002 and 2003, respectively), and resulting inbred fruits were smaller than outcrossed fruits in both years. No effect was detected for seed mass. The percentage of germination of inbred seeds was 15.1% and 6.0% lower than outcrossed seeds in 2002 and 2003, respectively. Inbred seedlings had shorter radicles, which translated to a 71.6% and 60.0% reduction in infection success compared with outcrossed plants in 2002 and 2003, respectively. Overall, our results revealed significant inbreeding depression on almost ever

Optimización de los medios de propagación y enraizamiento in vitro de las variedades “criollas” de vid para elaborar pisco

The protocols and culture media available for in vitro propagation and rooting of grapevine have not yet been adjusted to the creole varieties used for pisco making. In this paper we explored the use of culture media for the propagation of varieties Quebranta, Negra Criolla, Albilla, Italia and Torontel and for rooting varieties of Quebranta, Albilla and Torontel based on known standard culture media.To address this issue, 11 media derived from the standard propagation medium for grapevine (1X Murashige & Skoog medium, 3% sucrose, 1 mg/L benzilaminopurine, and 0,8% agar) with diminished medium strength and/or hormone concentration were tested. In addition, 5 concentrations of naphtalen acetic acid or indol acetic acid were tested for rooting. We found that Quebranta, Albilla, and Italia varieties show a better growth in the standard propagation medium; by contrast, Negra Criolla and Torontel grew better in media with diminished benzilaminopurine concentrations (0,25 and 0,5 mg/L, respectively). Quebranta rooted better with 80 μg/L naphtalen acetic acid or 2 mg/L indol acetic acid, while Albilla and Torontel showed better rooting results with 2 and 1 mg/L indol acetic acid, respectively.Los protocolos y medios disponibles para la propagación y enraizamiento in vitro de la vid no han sido ajustados todavía a las variedades “criollas” con las que se elabora el pisco. En este trabajo se exploró el uso de medios para la propagación de las variedades Quebranta, Negra Criolla, Albilla, Italia y Torontel, así como para el enraizamiento de las variedades Quebranta, Albilla y Torontel, a partir de los medios estándares reportados en la literatura científica. Para ello, se pusieron a prueba 11 variantes del medio estándar de propagación de vid (medio Murashige y Skoog 1X, 3% de sucrosa, 1 mg/L de benzilaminopurina y 0,8% de agar) en las que se combinaron reducciones en la fuerza del medio con reducciones en la concentración de hormona. Para el enraizamiento posterior, se probaron el ácido naftalen acético y el ácido indol acético a 5 concentraciones distintas por cada hormona. Los resultados mostraron que el mejor medio para la propagación de las variedades Quebranta, Albilla e Italia es el estándar; las variedades Negra Criolla y Torontel tuvieron mejor desempeño con una reducción de la concentración de benzilaminopurina a 0,25 y 0,5 mg/L, respectivamente. El mejor enraizamiento en la variedad Quebranta ocurrió con 80 μg/L de ácido naftalen acético y 2 mg/L de ácido indol acético; las variedades Albilla y Torontel tuvieron una mejor respuesta al ácido indol acético a concentraciones de 2 y 1 mg/L, respectivamente

Phenotypic plasticity in the holoparasitic mistletoe Tristerix aphyllus (Loranthaceae): consequences of trait variation for successful establishment

The ability of a genotype to respond to changes in the environment through modifications in the phenotype is adaptive when the plastic genotypes attain a higher fitness than non-plastic genotypes. In this study we examine whether parasite traits involved in host infection exhibit adaptive phenotypic plasticity to the heterogeneous host microenvironment. We focused on a host-parasite relationship characterized by the holoparasitic mistletoe Tristerix aphyllus and the cactus host Echinopsis chilensis. Unlike most mistletoes, whose seeds are deposited on the host branches, seeds of T. aphyllus are often deposited on the spines of the cactus. The extremely long radicles of T. aphyllus have been suggested to represent a parasite adaptation to overcome the barriers to infection imposed by the spines of cacti. However, plastic rather than canalized phenotypes may represent a better strategy in changing environments. We evaluated whether T. aphyllus exhibits adaptive plasticity in radicle length through a sire half-sib genetic design under field conditions in two contrasting microenvironments (seeds deposited on spines 4 and 28 mm from the host surface). We used phenotypic and genotypic selection analyses to evaluate the relationship between radicle length and seed establishment. Our results revealed significant phenotypic plasticity for radicle length and family level variation among maternal but not paternal familie

Local host adaptation and use of a novel host in the seed beetle Megacerus eulophus.

Spatial variation in host plant availability may lead to specialization in host use and local host adaptation in herbivorous insects, which may involve a cost in performance on other hosts. We studied two geographically separated populations of the seed beetle Megacerus eulophus (Coleoptera: Bruchidae) in central Chile: a population from the host Convolvulus chilensis (in Aucó) and a population from C. bonariensis (in Algarrobo). In Aucó C. chilensis is the only host plant, while in Algarrobo both C. bonariensis and C. chilensis are available. We tested local adaptation to these native host plants and its influence on the use of another, exotic host plant. We hypothesized that local adaptation would be verified, particularly for the one-host population (Aucó), and that the Aucó population would be less able to use an alternative, high-quality host. We found evidence of local adaptation in the population from C. chilensis. Thus, when reared on C. chilensis, adults from the C. chilensis population were larger and lived longer than individuals from the C. bonariensis population, while bruchids from the two populations had the same body size and longevity when reared on C. bonariensis. Overall, bruchids from the C. chilensis population showed greater performance traits than those from the C. bonariensis population. There were no differences between the bruchid populations in their ability to use the alternative, exotic host Calystegia sepium, as shown by body size and longevity patterns. Results suggest that differences in local adaptation might be explained by differential host availability in the study populations