The Interactive Effect of Elevated Carbon Dioxide, Temperature, and Water Deficit Stress on Growth and Flower Development of Petunia (Petunia ×hybrida)

Changes in climate, including increases in atmospheric CO₂ and temperature, and water deficit, present a challenge to agriculture. In order to cope with environmental stress plants utilize morphological and physiological mechanisms to survive and mitigate the stress. These three environmental factors, among other factors, play significant roles in plant growth and development. The goal of this research was to investigate plants’ morphological/physiological responses to the interaction of three abiotic environmental factors. Petunias were grown in growth chambers at two levels of CO₂ (400 and 800 µmol·mol^-1), two temperature regimes (21/18 and 28/25 °C day/night), and two water regimes (0.15 and 0.30 m³/m³) maintained by an automated irrigation system. To investigate the impact of simulated climate change, growth index, gas exchange, time to first fully open bloom, flower size, flower longevity and the number of flowers were measured. Preliminary results revealed that elevated CO₂ accelerated flowering time, mitigated the inhibitory effect of high temperature on flowering, and elevated temperature decreased the number of flowers per plant.