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Você está aqui: Página Inicial English Version Impacts of CO2

Impacts of CO2

The global atmospheric CO2 concentration has been increasing rapidly in the last decades and despite the international efforts for its reduction , it will probably continue increasing for decades and a long period will be necessary for it to return to the previous concentration. The effects of high CO2 atmospheric concentration are often observed in the host plant, resulting in alterations in the host-pathogen relationship. CO2 enrichment promotes changes in plant metabolism, growth and physiological processes. There is a significant increase in the photosynthetic rate and a decrease in the transpiration rate per unit leaf area, while total plant transpiration sometimes increases, due to the larger leaf area.

Despite evidence of beneficial effects of CO2 on the host plant, it is not well known if these effects will still take place in the presence of pathogens, pests and weeds or other limiting factors, particularly in tropical countries. Few studies were conducted under controlled conditions, which might not reflect plant responses in the field, where there are variations and interactions among temperature, precipitation, and other factors.

Studies of the effect of greenhouse gases should be performed with methods that allow changes only on the target variable, while the others remain constant. These studies become difficult due to the inability to create an environment free from structures and equipment necessary to expose the plant to the target gas to be tested. Therefore, the research groups in this area are focusing on conducting studies in conditions similar to the environment and leaving the structures extremely controlled.

The search for more realistic conditions has led to the use of open-top chambers (OTCs) or Free Air Carbon Dioxide Enrichment (FACE). The OTCs are suitable for studies with increased concentration of CO2 due to the possibility of conducting trials at all stages of plant development, with less interference from the structures, except for the reduction of solar radiation and a small increase in temperature caused by the plastic. Plants can be grown directly in soil. Studies in pots should be avoided because they may limit the root growth and change the soil structure. Moreover, using OTCs it is possible to obtain responses to the gas in natural conditions, including the daily fluctuations and seasonal climate. However, FACE experiments allow more natural conditions, because of the release of CO2 under field conditions.

In this Project the first FACE facility in the country was installed in Jaguariúna city - state of São Paulo and the installation of six OTCs experiments throughout the country (Belém, PA; Petrolina, PE; Sete Lagoas, MG; Londrina, PR; Jaguariúna, SP; and Vacaria, RS). In these studies the severity of diseases and pests, weeds, plant development, interaction with microorganisms, plant nutrition, production and others were evaluated. Climapest-FACE was designed to discover the effects of high CO2 concentration on coffee diseases, pests and weeds, as well as plant characteristics.  The studies with forest species, apple, peach, soybean, grape, corn, cotton, castor beans, forage crops, coffee, cassava and banana were conducted in OTCs.

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Coffee culture – FACE experimental area at Jaguariúna – SP - Brazil (Photo: Raquel Ghini – Embrapa Environment)


General Obje
ctive

Evaluate the impacts of increased atmospheric CO2 concentration on plant diseases, pests, and weeds of important crops for the Brazilian agribusiness in order to develop adaptation alternatives for the control of these problems.

Specific Objectives

- Install the Free Air CO2 Enrichment (FACE) and open-top chamber (OTC) experiments;

- Evaluate the impacts of increased CO2 concentration on the plant diseases, pests, and weeds in forest species, apple, peach, soybean, grape, corn, cotton, castor beans, forage crops, coffee, cassava, and banana.