CEAZA
Nutritional Aspects of Six Quinoa (Chenopodium quinoa Willd.) Ecotypes from three Geographical Areas of Chile. Chilean
Miranda, M., Vega-Gálvez, A., Quispe-Fuentes, I., Rodríguez, M., Maureira, H., & Martínez, E.
This study explored the diversity of the quinoa crop in Chile from a nutritional perspective. Nutritional properties, minerals, vitamins, and saponin content were assessed in seeds of six Chilean quinoa (Chenopodium quinoa Willd.) ecotypes grown in three main production areas with distinctive climatic and edaphic conditions: Ancovinto and Cancosa in the North-Altiplano or High Plateau, Cáhuil and Faro in the central coastal area, and Regalona and Villarrica in the south of the country. There were significant differences (P < 0.05) in all the nutritional properties of the quinoa seeds in all three areas. Quinoa of the Villarrica ecotype showed the highest protein content (16.10 g 100 g-1 DM) and the highest content of vitamins E and C (4.644 ± 0.240 and 23.065 ± 1.119 mg 100 g-1 DM, respectively). The highest content of vitamins B1 (0.648 ± 0.006 mg 100 g-1 DM) and B3 (1.569 ± 0.026 mg 100 g-1 DM) was found in the Regalona ecotype, while the highest value of vitamin B2 (0.081 ± 0.002 mg 100 g-1 DM) occurred in the Ancovinto ecotype. Potassium was the most abundant mineral with a maximum value of 2325.56 mg 100 g-1 DM in the Cancosa ecotype. Saponin content varied from 0.84 g 100 g-1 DM in the Villarrica ecotype to 3.91 g 100 g-1 DM in the Cáhuil ecotype. Significant differences were found among the Chilean quinoa ecotypes grown under different climatic conditions; however, all the quinoa seeds exhibited a high nutritional value. These results are compatible with the genetic differences previously observed in the three geographical areas under study. Thus, if more studies are conducted to show the particular properties of quinoa from specific areas, it would be possible in the future to coin the term "controlled designation of origin" (appellation d'origine contrólée) and add commercial value to Chilean quinoa seeds in the domestic and international markets.
Año: 2012
Palabras claves: Quinoa, vitamins, minerals, saponin content, nutritional properties.
Referencia APA: Miranda, M., Vega-Gálvez, A., Quispe-Fuentes, I., Rodríguez, M., Maureira, H., & Martínez, E. (2012). Nutritional Aspects of Six Quinoa (Chenopodium quinoa Willd.) Ecotypes from three Geographical Areas of Chile. Chilean. J. Agric. Res., 72(2), 175-181.
The trade-off between cold resistance and growth determines the Nothofagus pumilio treeline.
Molina-Montenegro, M., Gallardo-Cerda, J., Flores, T., & Atala, C.
The upper and poleward limit of tree distribution are usually determined by abiotic factors such as low temperature and strong winds. Thus, cold resistance is a key element for survival in high altitudes and latitudes where conditions can reduce plant growth. A trade-off between resource allocation to cold resistance and growth could emerge in populations frequently exposed to low temperatures like those in the treeline zone. We studied annual height growth and ice nucleation temperature in Nothofagus pumilio (Nothofagaceae) populations growing in its extremes of altitudinal distribution and in 3 sites situated on a latitudinal gradient in the Chilean Andes. Additionally, gas exchange, water and nitrogen use efficiency and total soluble sugar (TSS) were also measured as possible mechanisms for survival in high altitudes. Individuals from the treeline populations showed lower annual height growth and lower ice nucleation temperatures compared with those from lower populations. In the same way, individuals from more poleward populations showed lower annual height growth and lower ice nucleation temperatures. Gas exchange, water and nitrogen use efficiency and TSS were also higher in the high altitude populations. The results obtained support the hypothesis of trade-off, because the upper and poleward populations showed more cold resistance but a lower height growth. Additionally, we show that cold resistance mechanisms do not impact the physiological performance, suggesting possible adaptation of the high altitude populations. Low temperatures may be affecting cellular growth instead of photosynthesis, creating a pool of carbohydrates that could participate in cold tolerance. Other abiotic and biotic factors should be also assessed to fully understand the distributional range of Nothofagus species.
Año: 2012
Palabras claves: Height growth, Los Andes, Photosynthesis, Treeline, Environmental gradients, Ice nucleation.
Referencia APA: Molina-Montenegro, M., Gallardo-Cerda, J., Flores, T., & Atala, C. (2012). The trade-off between cold resistance and growth determines the Nothofagus pumilio treeline. Plant Ecol, 213(1), 133-142.
Upwelling response to atmospheric coastal jets off central Chile: A modeling study of the October 2000 event.
Renault, L., Dewitte, B., Marchesiello, P., Illig, S., Echevin, V., & Cambon, G., Ramos, M., Astudillo, O., Minnis, P., Ayers, J.K.
The spatial and temporal variability of nearshore winds in eastern boundary current systems affect the oceanic heat balance that drives sea surface temperature changes. In this study, regional atmospheric and oceanic simulations are used to document such processes during an atmospheric coastal jet event off central Chile. The event is well reproduced by the atmospheric model and is associated with the migration of an anomalous anticyclone in the southeastern Pacific region during October 2000. A robust feature of the simulation is a sharp coastal wind dropoff, which is insensitive to model resolution. As expected, the simulated oceanic response is a significant sea surface cooling. A surface heat budget analysis shows that vertical mixing is a major contributor to the cooling tendency both in the jet core area and in the nearshore zone where the magnitude of this term is comparable to the magnitude of vertical advection. Sensitivity experiments show that the oceanic response in the coastal area is sensitive to wind dropoff representation. This is because total upwelling, i.e., the sum of coastal upwelling and Ekman pumping, depends on the scale of wind dropoff. Because the latter is much larger than the upwelling scale, coastal wind dropoff has only a weak positive effect on vertical velocities driven by Ekman pumping but has a strong negative effect on coastal upwelling. Interestingly though, the weakening of coastal winds in the dropoff zone has a larger effect on vertical mixing than on vertical advection, with both effects contributing to a reduction of cooling.
Año: 2012
Palabras claves: atmospheric coastal jets; eastern boundary current systems; numerical simulation; ocean/atmosphere interactions; upwelling; wind dropoff
Referencia APA: Renault, L., Dewitte, B., Marchesiello, P., Illig, S., Echevin, V., & Cambon, G., Ramos, M., Astudillo, O., Minnis, P., Ayers, J.K. (2012). Upwelling response to atmospheric coastal jets off central Chile: A modeling study of the October 2000 event. J. Geophys. Res., 117(C2), n/a-n/a.
Interspecific Competition for Shelters in Territorial and Gregarious Intertidal Grazers: Consequences for Individual Behaviour.
Aguilera, M. & Navarrete, S.
Experiments have shown that interspecific interactions within consumer guilds can alter patterns of distribution, abundance and size of species. Plastic behavioural responses can be modulated by agonistic interactions. In many cases, consumers compete for space and shelters, and these interactions change the manner in which they exploit food. This study investigates the consequences of competition in the spatial and temporal organization of behaviour of intertidal grazers, which share algal resources and the use of rock crevices while resting, but exhibit different body sizes, spatial behaviour and foraging modes. We evaluate interaction strength between small gregarious Siphonaria lessoni and the larger territorial keyhole limpet Fissurella crassa and between S. lessoni and the medium-size gregarious chiton Chiton granosus. Using field manipulations and artificial arenas in the laboratory, we tested whether the use of crevices, micro-spatial distribution and activity are modified by the density of conspecifics and the presence of heterospecifics. Our results show that small-scale spatial segregation observed in the field between S. lessoni and C. granosus result from species-specific differences in habitat use. In turn, we found evidence that spatial segregation between F. crassa and S. lessoni results from highly asymmetric interference competition in the use of shelters. The presence of F. crassa reduced the use of crevices and growth rates of S. lessoni. Effects on growth rates are assumed to result from exposure to harsh environmental conditions rather than food limitation. Thus, neither gregarious behaviour nor differences in activity were sufficient to prevent competition with the larger grazer. Our study illustrates the importance of competition for shelters, which results in behavioural changes of the smaller-sized species, and how these plastic responses can translate into differences in growth rates. Use of shelters can thus be modulated by environmental conditions in a species-specific as well as an interactive manner within consumers’ guilds.
Año: 2012
Palabras claves: Foraging, Shelters, Herbivory, Physiological parameters, Species interactions, Trophic interactions, Food, Predation.
Referencia APA: Aguilera, M. & Navarrete, S. (2012). Interspecific Competition for Shelters in Territorial and Gregarious Intertidal Grazers: Consequences for Individual Behaviour. Plos ONE, 7(9), e46205.
What do we know about high-altitude precipitation in the semi-arid Andes of Chile?
Bourgin P, Andreassian V, Gascoin S, Valery A.
Mapping precipitations on a regular grid is often required for hydrological and ecological modelling. The spatial interpolation methods are generally used to estimate such a distribution from ground-based measurements. In the case of mountainous areas, the estimation of precipitation amounts is still a challenging task and the results of spatial interpolation should be verified as much as possible. Here we describe a three-steps method for the validation of a precipitation map. This is used in the context of a mountainous semi-arid region, the Norte Chico in Chile (26°S-32°S). The implementation of this validation method showed the benefits of an interpolation method developed by Valéry [2010] for mountainous areas. The hydrological balance of the high-altitude watersheds is now more realistic.
Año: 2012
Palabras claves: Precipitation, spatial interpolation method, extrapolation, altitude, altitudinal corrections, validation, water equivalent, water balance.
Referencia APA: Bourgin P, Andreassian V, Gascoin S, Valery A. (2012). Que sait-on des précipitations en altitude dans les Andes semi-arides du Chili?. La Houille Blanche. 2012;(2):12-17.