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Most experts who study global trends in climate change agree that CO2 levels and temperatures show an atypical and sustained increase in recent years. The present study evaluated the simulated effect that would cause high levels of CO2 (380 and 420 μmol mol-1), temperatures (28, 30 and 32 ºC) and high levels of photosynthetically active radiation (14 levels between 0 and 2000 μmol m-2 s-1), and their interactions, on some important aspects in the physiology of three native species cultivated by small producers of La Mojana: creole eggplant, bogotano rice and cocoa. The light saturation point (PSL), light compensation point (PCL), maximum net photosynthesis rate (ANmax) and dark breathing rate (Ro) were determined. The results indicate that the native eggplant would be affected if the radiation reached 2000 μmol m-2 s-1 and the temperature rose to 30 and 32 ºC in either of the two environmental CO2 scenarios. Bogota rice showed a relative tolerance to high temperatures under normal or increased CO2 conditions. In cocoa, the physiological response was more sensitive and would be affected mainly at high temperatures. The results confirm that the photosynthetic stability in bogotano rice shows that it could adapt to high temperature conditions under the two environmental CO2 scenarios, while Creole eggplant and cocoa would be sensitive to high temperatures. [ABSTRACT FROM AUTHOR]

A greater efficiency of rice cultivation is based on knowing its characteristics in terms of growth and yield according to the environmental supply. This research aimed at determining the dry mass (DM) g, leaf area (LA) cm2, absolute growth rate (AGR) g day-1, relative growth rate (RGR) g g-1 day-1, net assimilation rate (NAR) g cm-2 dia-1, leaf area ratio (LAR) cm-2 day-1 and leaf area index (LAI) and yield components of plant height, panicles per m2, grains per panicle, weight of 1000 grains and yield t ha-1, of Fedearroz 2000, Fedearroz 50, Fedearroz Mocarí and Fedearroz 473 cultivars under irrigation, during the sowing season ranging from october to december, with a randomized block design with factorial arrangement 4x3 and four replications, while doing sampling for 15 days. The results showed high differences between sowing times, where the highest values of DM were presented in october, the LAI in November, RGR, RGR, NAR and LAR in october and november, where the cultivars showed more stability to environmental factors. The variables plant height, panicles per m2, numbers of grains per panicle and weight of 1000 grains did not present significant difference in one month to another; However the cultivars fedearroz 2000 and fedearroz 50 reached the maximum values in november, the yield presented highly significant differences in the seasons of november and december for the Fedearroz 2000 and Fedearroz 473 cultivars. To conclude, the greater physiological efficiency of the cultivars is presented in the sowing seasons of november and december. [ABSTRACT FROM AUTHOR]

The cyanobacteria Nostoc commune contains bioactive compounds with antimicrobial activity and high potential to control of phytopathogens. The objective of this work was to determine the in vitro effect of sonicated biomass of these cyanobacteria on the growth of Fusarium oxysporum. The biomass of N.commune was dissolved in sterile distilled water and subjected to centrifugation processes and ultrasound-assisted cell rupture. The antifungal effect was evaluated using the disk diffusion technique (Kirby-Bauer) in a PDA (Potato Dextrose Agar) medium. In the center of the Petri dish, an agar disk (0.7 cm) with pure mycelium of the fungus was placed in the center of the Petri dish and, around it, four filter paper disk impregnateed with the algae extract (0.7 cm) were placed. The radial growth of the pathogen was measured in the presence and absence of N. commune, until the control covered the entire Petri dish to assess the Percentage of Radial Inhibition of the pathogen (PICR %). The growth rate of the fungus was lower in the initial stages of measurement and the PICR fluctuated between 33 and 58%. However, there were no inhibition halos in the growth of the fungus, it is assumed that the antifungal effect of the cyanobacteria was not permanent over the time, but it could be potentiated by improving the extraction process of the extract. [ABSTRACT FROM AUTHOR]