2018 ASHS Annual Conference

Enhancement of carbon dioxide (CO₂) in the atmosphere has received great attention due to its potential repercussion on global warming and direct effects on the vegetation, especially with a potential increase in atmospheric CO₂ level from 400 μmol∙mol^-1 to 1000 μmol∙mol^-1 by the end of the 21^st century according to the currents environmental studies. Therefore, development of new technologies on controlled environment conditions are needed to investigate plant response to CO₂ enhancements and its possible repercussion on world food security. In the present study, we aimed to evaluate a modified open-top chamber (OTC), designed and constructed based on previous OTC experiences, which provides precise control of CO₂ under different concentrations, with excellent control of air temperature and humidity. To test the functionality of the modified OTC, Goji berry (Lycium barbarum L.) plants were grown from May to October on 2017 inside the chambers. Real-time data of CO₂ concentration, temperature, and air relative humidity of the chambers were collected. As a result, the average CO₂ levels obtained in the chamber during the study period was 369.33 μmol∙mol^-1 for ambient conditions, while elevated group 1 and group 2 showed concentrations of 558.35 μmol∙mol^-1and 772.71 μmol∙mol^-1 respectively. The fluctuation for elevated group 1 ranged from 551.82 to 572.40 μmol∙mol^-1 with a variation amplitude of 20.57 μmol∙mol^-1. In the elevated group 2, the range of CO2 concentration was from 756.71 to 779.79 μmol∙mol^-1 with variation amplitude of 23.09 μmol∙mol^-1. In addition, no significant differences were found in temperature and air relative humidity among the chambers treatments (P > 0.05). Meanwhile, the measured amounts of fructose, glucose, sucrose and starch contents of Goji berry fruits revealed that the sugar content of the fruit was significantly reduced under elevated group 2 CO₂ concentration, there was a significant increase (P<0.05) in the activity of sucrose cleavage enzyme and a decrease in the sucrose synthetic enzyme. These results demonstrated precise control of CO₂ concentration, temperature, and humidity inside the modified OTC chambers, showing an excellent development of CO₂ effect improvement on Goji berry, and it can be used to test climate change response in other plant species.