Efeitos do aumento da concentração de CO2 atmosférico e da elevação da temperatura em plantas e suas interações biológicas

Abstract

This thesis evaluated some of the effects of increased atmospheric CO2 and temperature on selected agricultural species and their interactions. The thesis was structured into four chapters: Chapter I presents the current scenario of climate change and how the research on this topic in Brazil has been done; Chapter II assesses the impact of increased CO2 and temperature on soybean Glycine max (L.) Merr biological interactions; Chapter III studies the effect of increased CO2 and temperature predicted for the year 2100, on the photosystem II tolerance of soybean plants to acute heat shock in vitro; Chapter IV evaluates the physiological responses to drought and acute heat shock induced in vitro in two C4 plants species (maize and millet) grown under increased CO2 concentration and temperature. The results of these studies indicate that each species respond differently to an increase of atmospheric CO2 and temperature. Soybean showed differences in the nutritional quality of leaves grown under increased CO2 and temperature, and it affected interactions with endophytic fungi and the caterpillar Spodoptera frugiperda. However, the studied climatic change decreased the thermotolerance of photosystem II soybean, resulting in the reduction of the temperature of 50% of the maximum quantum yield. However, the increase in atmospheric CO2 concentration and temperature improved cell tolerance to water deficit and acute thermal shock of C4 metabolism species. Corn benefited most from the high CO2 concentration, while millet, high temperature. These results will add to the knowledge about the effects of these climate change factors in agricultural species, and assist in decision making to propose mitigating actions.