Abstract

JEREZ-JAIMES, Javier H.  and  BERNAL-PEREZ, María C.. ESTIMATE OF ATMOSPHERIC CO₂ OF THE BOGOTÁ CITY (COLOMBIA), UTILIZING LEAVES OF GINKGO BILOBA L. (GINKGOACEAE). Actu Biol [online]. 2007, vol.29, n.86, pp.79-85. ISSN 0304-3584.

Ginkgo biloba L. (Ginkgoaceae) is considered the last survivor of a group of plants which exhibited great diversity in the Mesozoic era, and is now considered a 'living fosil'. The individuals of this species are especially sensitive to the changes in the CO₂ concentrations, showing an inverse relation with stomatal density. According to this, the stomatal pattern in G. biloba is not defined by the age of plants. Ginkgo biloba is not a native species but it presents a strong stomatal plasticity. In this study, thirty leaves were collected from three two-year specimens cultivated in the 'Jardín Botánico José Celestino Mutis' in Bogotá. From the collected material, six leaves were selected randomly and were treated later with sodium hypochlorite. From each one of these leaves, three subsamples were taken at random. During this process, the adaxial cuticles were removed and colored with tionona for later observation through an optical microscope (400X). The stomatal density ( = 69.39 estomata/mm²; S = 16.93) and the stomatal index ( = 12.32; S = 3.68) were calculated. Based on historical data of CO2 concentrations and stomatal index a simple linear regression was elaborated (r = -0.99; p = 0.000) and the inverse equation was determined [CO₂ = (SI - 33,427) / (-0.0704)]. Taking into account this procedure, it was estimated for Bogotá an atmospheric CO₂ concentration between 381 and 384 parts per million (ppm.).

Keywords : Global warming; greenhouse gases; paleoclimate; stomatal index; stomatal density.

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