Rómulo Oses

Quinoa biodiversity and sustainability for food security under climate change. A review

Climate change is rapidly degrading the conditions of crop production. For instance, increasing salinization and aridity is forecasted to increase in most parts of the world. As a consequence, new stress-tolerant species and genotypes must be identified and used for future agriculture. Stress-tolerant species exist but are actually underutilized and neglected. Many stress-tolerant species are indeed traditional crops that are only cultivated by farmers at a local scale. Those species have a high biodiversity value. Besides, the human population will probably reach nine billion within coming decades. To keep pace with population growth, food production must increase dramatically despite the limited availability of cultivable land and water. Here, we review the benefits of quinoa, Chenopodium quinoa Willd., a seed crop that has endured the harsh bioclimatic conditions of the Andes since ancient times. Although the crop is still mainly produced in Bolivia and Peru, agronomic trials and cultivation are spreading to many other countries. Quinoa maintains productivity on rather poor soils and under conditions of water shortage and high salinity. Moreover, quinoa seeds are an exceptionally nutritious food source, owing to their high protein content with all essential amino acids, lack of gluten, and high content of several minerals, e.g., Ca, Mg, Fe, and health-promoting compounds such as flavonoids. Quinoa has a vast genetic diversity resulting from its fragmented and localized production over the centuries in the Andean region, from Ecuador to southern Chile, and from sea level to the altiplano. Quinoa can be adapted to diverse agroecological conditions worldwide. Year 2013 has therefore been declared the International Year of Quinoa by the United Nations Food and Agriculture Organization. Here, we review the main characteristics of quinoa, its origin and genetic diversity, its exceptional tolerance to drought and salinity, its nutritional properties, the reasons why this crop can offer several ecosystem services, and the role of Andean farmers in preserving its agrobiodiversity. Finally, we propose a schematic model integrating the fundamental factors that should determine the future utilization of quinoa, in terms of food security, biodiversity conservation, and cultural identity.

Assessing the importance of human activities for the establishment of the invasive Poa annua in Antarctica

Because of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua. In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica, in order to unravel the effects of physical soil disturbance on the establishment and survival of P. annua. We found a positive correlation between abundance of P. annua and level of soil disturbance, and that survival of P. annua was 33% higher in sites with disturbed soil than non-disturbed. Finally, we found that disturbance conditions increased germination for P. annua, whereas for native species germination in experimentally disturbed soil was either unchanged or reduced compared to undisturbed soil. Our results indicate that human activities that modify abiotic soil characteristics could play an important role in the abundance of this invasive species. If the current patterns of human activities are maintained in Antarctica, the establishment success and spread of P. annua could increase, negatively affecting native flora.

Is Physiological Performance a Good Predictor for Fitness? Insights from an Invasive Plant Species

Is physiological performance a suitable proxy of fitness in plants? Although, several studies have been conducted to measure some fitness-related traits and physiological performance, direct assessments are seldom found in the literature. Here, we assessed the physiology-fitness relationship using second-generation individuals of the invasive plant species Taraxacum officinale from 17 localities distributed in five continents. Specifically, we tested if i) the maximum quantum yield is a good predictor for seed-output ii) whether this physiology-fitness relationship can be modified by environmental heterogeneity, and iii) if this relationship has an adaptive consequence for T. officinale individuals from different localities. Overall, we found a significant positive relationship between the maximum quantum yield and fitness for all localities evaluated, but this relationship decreased in T. officinale individuals from localities with greater environmental heterogeneity. Finally, we found that those individuals from localities where environmental conditions are highly seasonal performed better under heterogeneous environmental conditions. Contrarily, under homogeneous controlled conditions, those individuals from localities with low environmental seasonality performed much better. In conclusion, our results suggest that the maximum quantum yield seem to be good predictors for plant fitness. We suggest that rapid measurements, such as those obtained from the maximum quantum yield, could provide a straightforward proxy of individual’s fitness in changing environments.

Root-endophytes improve the ecophysiological performance and production of an agricultural species under drought condition

Antarctic root-endophytes can improve the physiological tolerance and productivity of lettuce crops by means of several different physiological and molecular mechanisms, and could be a successful strategy to maximize water use efficiency and hence maintain an optimal yield in zones affected by desertification. Thus, application of antarctic root-endophytes to different crops could be a biotechnological tool for food security.

Genetic diversity of Colobanthus quitensis across the Drake Passage

The Drake Passage arises as a likely route for gene flow into Antarctica, as it is the shortest path between this continent and the rest of the world. Despite this, long-distance dispersion into Antarctica could be particularly complex for terrestrial biota. To compare the levels of genetic diversity between Antarctic and South American populations of the Antarctic pearlwort, Colobanthus quitensis, we conducted the first estimation of genetic diversity in this species using amplified fragment length polymorphism. Four populations across the Drake Passage were selected and their genetic composition was characterized. Differences among the levels of genetic diversity were found between the populations analysed as well as between their allelic identities. However, interestingly, their spatial distribution across the Drake Passage suggests a north-to-south gradient of increasing genetic diversity.

Impact of mycorrhizae and irrigation in the survival of seedlings of Pinus radiata D. Don subject to drought

En condiciones de sequia, las plantas aumentan la probabilidad de sobrevivir ajustando sus rasgos funcionales y por medio de asociaciones biologicas. Las asociaciones micorricicas y el riego artificial aumentan la sobrevivencia en condiciones de sequia, especialmente en etapas tempranas del desarrollo, cuando las plantas son mas sensibles. En Chile, Pinus radiata es la especie forestal mas importante. Se planta principalmente en Chile central, donde se predice que las precipitaciones disminuiran en un 40% y cambiara su frecuencia en el futuro debido al cambio climatico. Rhizopogon luteolus es una ectomicorriza usualmente asociada a especies de Pinus y se ha encontrado que aumenta la tolerancia a la sequia. Se analizo el efecto de la inoculacion de R. luteolus en la sobrevivencia y rasgos funcionales de plantulas de P. radiata expuestas a dos tratamientos de riego. Estos tratamientos simulan precipitaciones control (50 ml) y reducidas a un 40% (20 ml). Tambien se evaluo el efecto combinado de la cantidad (20 y 50 ml) y frecuencia (cada 5, 10 y 30 dias) de riego en las mismas variables. La inoculacion con R. luteolus aumento la sobrevivencia pero redujo el tamano de las plantulas. La cantidad de riego afecto la sobrevivencia de las plantas solo en la frecuencia intermedia de riego, pero no en las frecuencias alta y baja. La frecuencia mas baja, normal para el verano de Chile central, resulto en -80% de mortalidad de plantulas. La mayoria de los rasgos funcionales no fueron afectados por la frecuencia o cantidad de riego, pero si por la micorrizacion. La inoculacion con micorrizas, en conjunto con algun tipo de riego artificial, podria ser una posible estrategia para lidiar con eventos de sequia prolongada.

Effect of water availability on physiological performance and lettuce crop yield (Lactuca sativa)

M.A. Molina-Montenegro, A. Zurita-Silva, and R. Oses. 2011. Effect of water availability on physiological performance and lettuce crop yield (Lactuca sativa). Cien. Inv. Agr. 38(1): 65-74. Water is essential for plants, affecting the majority of the physiological processes related to growth and productivity. Water shortage is one of the most common factors that limit crop productivity worldwide. Many cultivars have elevated water requirements, nevertheless in some countries due to global climate change effects, the availability of water for irrigation is becoming limited. In fact, current models of climate changes predict that central Chile will be a sensitive zone where precipitation will drastically decrease. In this study, the variation of gas exchange and production of fresh biomass in a lettuce cultivar, grown under different water availability regimes, was evaluated. Additionally, the concentration of total soluble sugar and water use efficiency (WUE) as mechanisms related to water shortage responses were also evaluated. Overall, individuals with the lowest water availability (50%) showed lower gas exchange and fresh biomass values than their conspecifics grown in optimal irrigated conditions. On the other hand, those individuals with moderate water shortage showed the highest concentration of total soluble sugars and WUE. Our results suggested that cultures exposed to extensive or intense drought events, could be negatively affected in both physiological performance and productivity. Nevertheless, slight decreases in water availability can enable lettuce plants to exhibit a high WUE, maintaining high levels of physiological performance and productivity.

Biological Interactions and Simulated Climate Change Modulates the Ecophysiological Performance of Colobanthus quitensis in the Antarctic Ecosystem.

Most climate and environmental change models predict significant increases in temperature and precipitation by the end of the 21st Century, for which the current functional output of certain symbioses may also be altered. In this context we address the following questions: 1) How the expected changes in abiotic factors (temperature, and water) differentially affect the ecophysiological performance of the plant Colobanthus quitensis? and 2) Will this environmental change indirectly affect C. quitensis photochemical performance and biomass accumulation by modifying its association with fungal endophytes? Plants of C. quitensis from King George Island in the South Shetland archipelago (62°09′ S), and Lagotellerie Island in the Antarctic Peninsula (65°53′ S) were put under simulated abiotic conditions in growth chambers following predictive models of global climate change (GCC). The indirect effect of GCC on the interaction between C. quitensis and fungal endophytes was assessed in a field experiment carried out in the Antarctica, in which we eliminated endophytes under contemporary conditions and applied experimental watering to simulate increased precipitation input. We measured four proxies of plant performance. First, we found that warming (+W) significantly increased plant performance, however its effect tended to be less than watering (+W) and combined warming and watering (+T°+W). Second, the presence of fungal endophytes improved plant performance, and its effect was significantly decreased under experimental watering. Our results indicate that both biotic and abiotic factors affect ecophysiological performance, and the directions of these influences will change with climate change. Our findings provide valuable information that will help to predict future population spread and evolution through using ecological niche models under different climatic scenarios.

Hongos endófitos antárticos como herramienta para la reintroducción de especies nativas en zonas áridas

La restauracion ecologica es la actividad deliberada que acelera la recuperacion de un sistema degradado por accion directa o indirecta de la intervencion humana. Las zonas xerofiticas estan entre los ecosistemas mas degradados donde la baja disponibilidad hidrica hace que los planes de reintroduccion sean poco exitosos y extremadamente costosos. La aplicacion de hongos endofitos a raices ha sido reportada como una exitosa estrategia para mantener o mejorar el desempeno ecofisiologico y supervivencia en diferentes especies de arbustos y arboles. En ambientes climaticamente extremos, los endofitos han mostrado proporcionar beneficios en terminos de supervivencia y crecimiento a la vegetacion que se asocia a ellos. En el presente trabajo mostramos como la inoculacion con endofitos aislados desde plantas creciendo en la Antartica mejoran la supervivencia y eficiencia en el uso del agua para el riego en especies nativas de las formaciones xerofiticas: Flourensia thurifera, Senna cumingii y Puya berteroniana. En general, los resultados muestran que la presencia de endofitos mejoro la supervivencia de las tres especies nativas. Por otro lado, la presencia de endofitos mejoro la eficiencia en el uso del agua para el riego, permitiendo alcanzar altos porcentajes de supervivencia en plantas con una reduccion en el agua requerida. Los resultados preliminares obtenidos en este estudio sugieren que la aplicacion de endofitos antarticos podria ser considerada como una estrategia exitosa para proyectos futuros y programas de reintroduccion en zonas aridas y semi-aridas de Chile.