A photochemical model of the atmosphere constitutes a non-linear, non-autonomous dynamical system, enforced by the Earth＇s rotation. Some studies have shown that the region of the mesopause tends towards non-linear r...A photochemical model of the atmosphere constitutes a non-linear, non-autonomous dynamical system, enforced by the Earth＇s rotation. Some studies have shown that the region of the mesopause tends towards non-linear responses such as period-doubling cascades and chaos. In these studies, simple approximations for the diurnal variations of the photolysis rates are assumed. The goal of this article is to investigate what happens if the more realistic, calculated photolysis rates are introduced. It is found that, if the usual approximations-sinusoidal and step fiunctions—are assumed, the responses of the system axe similar： it converges to a 2-day periodic solution. If the more realistic, calculated diurnal cycle is introduced, a new 4-day subharmonic appear.展开更多
Different crop varieties can respond in different ways to the climatic variations at local scale. Thus, in order to maximize the yield for a determined crop, the response of different varieties submitted to local clim...Different crop varieties can respond in different ways to the climatic variations at local scale. Thus, in order to maximize the yield for a determined crop, the response of different varieties submitted to local climatic conditions should be assessed. The main goal of this study was to evaluate the ecophysiological responses of two varieties of Quinoa (PRP and BO78) submitted to different conditions of thermal amplitude. We performed two experiments in both greenhouse and in 3 sites on experimental-field where were evaluated survival, photochemical efficiency, plant growth and dry biomass in both varieties and compared them with the mean of the thermal conditions recorded during the last 16 years in the Coquimbo Region, Chile. Overall, individuals of BO78 showed higher performance in the sites with lower thermal amplitude than those of PRP. By contrast, in sites with higher thermal amplitude individuals of PRP showed better survival, physiological performance and biomass and therefore higher performance. Our results suggest that while BO78 showed an ecotypic strategy, the PRP showed a plastic strategy to maintain higher performance in sites with moderate and high climatic variability. We consider that under an increase in desertification, semi-arid areas would be available for stress tolerant crops like Quinoa, but the success for the food security in these regions may depend upon the variety used.展开更多
文摘A photochemical model of the atmosphere constitutes a non-linear, non-autonomous dynamical system, enforced by the Earth＇s rotation. Some studies have shown that the region of the mesopause tends towards non-linear responses such as period-doubling cascades and chaos. In these studies, simple approximations for the diurnal variations of the photolysis rates are assumed. The goal of this article is to investigate what happens if the more realistic, calculated photolysis rates are introduced. It is found that, if the usual approximations-sinusoidal and step fiunctions—are assumed, the responses of the system axe similar： it converges to a 2-day periodic solution. If the more realistic, calculated diurnal cycle is introduced, a new 4-day subharmonic appear.
文摘Different crop varieties can respond in different ways to the climatic variations at local scale. Thus, in order to maximize the yield for a determined crop, the response of different varieties submitted to local climatic conditions should be assessed. The main goal of this study was to evaluate the ecophysiological responses of two varieties of Quinoa (PRP and BO78) submitted to different conditions of thermal amplitude. We performed two experiments in both greenhouse and in 3 sites on experimental-field where were evaluated survival, photochemical efficiency, plant growth and dry biomass in both varieties and compared them with the mean of the thermal conditions recorded during the last 16 years in the Coquimbo Region, Chile. Overall, individuals of BO78 showed higher performance in the sites with lower thermal amplitude than those of PRP. By contrast, in sites with higher thermal amplitude individuals of PRP showed better survival, physiological performance and biomass and therefore higher performance. Our results suggest that while BO78 showed an ecotypic strategy, the PRP showed a plastic strategy to maintain higher performance in sites with moderate and high climatic variability. We consider that under an increase in desertification, semi-arid areas would be available for stress tolerant crops like Quinoa, but the success for the food security in these regions may depend upon the variety used.
