Effects of Elevated Temperature and Carbon Dioxide Concentrations on Aromatic Compounds of Stevia rebaudiana

A global rise in CO2 concentration and temperature levels can impact the living part of the earth including the plants. Stevia or candy leaf (Stevia rebaudiana Bertoni) is a medicinal aromatic plant that produces several useful chemical compounds. Studies were carried out in a fully automated greenhouse in order to determine the response of aromatic compounds of stevia leaves to different CO2 concentrations and temperature levels. This study had four treatments including (1) 26 +/- 1/16 +/- 1 degrees C day/night temperature plus 400 +/- 50 ppm CO2 concentration [control], (2) 29 +/- 1/19 +/- 1 degrees C day/night temperature plus 600 +/- 50 ppm CO2 concentration, (3) 32 +/- 1/22 +/- 1 degrees C day/night temperature plus 800 +/- 50 ppm CO2 concentration and (4) 35 +/- 1/25 +/- 1 degrees C day/night temperature plus 1000 +/- 50 ppm CO2 concentration. Results of the study showed that yield of total aromatic compounds ranged between 12.65 and 13.65 mu g/g for stevia . Generally, concentrations of the compounds such as ketones, aldehydes and alcohols were decreased with increase in concentration of CO2 and temperature. Terpenes were the compounds whose concentrations were increased with increase in concentration of CO2 and temperature. The climatic conditions did not cause a significant change in the aromatic compounds of stevia.