2017 ASHS Annual Conference

Plants are sessile organisms and are often exposed to environmental stresses. In order to cope with such stresses, plants utilize morphological and physiological mechanisms to mitigate the impacts of stresses for survival. Environmental stresses could damage flowers that are critical for seed and fruit production. Reproductive success depends on the development of healthy flowers and the process of flower development is particularly vulnerable to environmental changes. Therefore, it is important to investigate the effects of environmental factors on the flower development as well as the underlying molecular mechanisms that control plants’ response to the environment changes. The goal of this research was to investigate the effects of elevated CO₂, temperature and water deficit stress on flower development. The main effects and interaction of these abiotic factors, simulating climate change, on growth and flower development were examined. 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 irrigation levels (0.15 and 0.30 m³·m^-3). The moisture levels of the growing media were maintained by an automated irrigation system. The number of flowers, flower size, and flowering time were examined. Gene expression patterns, using a semi-quantitative real-time PCR, of selected genes involved in stress responses and flower development were examined. Fewer flowers were produced on plants grown under the elevated temperature and water deficit condition at ambient CO₂. The size of the flowers decreased under elevated CO₂. Reductions in flower number and size may render the plants less attractive to pollinators, which could be detrimental to seed production and yield in agricultural crops. Flowering time was also delayed with elevated CO₂, but accelerated with higher temperature. The altered pattern of flowering time under climate change conditions could result in an asynchrony between crops and their pollinators.