text: Floral scent emissions of most flowering plants vary predictably throughout the day, following a circadian rhythm. This variation is controlled by light intensity. Maximal emissions coincide with peaks of the highest activity of visiting pollinators. For instance, snapdragon flowers, mostly pollinated by bees, have the highest emissions at noon, whereas nocturnally-visited tobacco plants have the highest emissions at night.
  Floral scent emissions also vary along with floral development, with the highest emissions at anthesis, i.e. when the flower is fecund (highly fertile), and reduced emissions after pollination, probably due to mechanisms linked with fecundation. In tropical orchids, floral scent emission is terminated immediately following pollination, reducing the expenditure of energy on fragrance production. In petunia flowers, ethylene is released to stop the synthesis of benzenoid floral volatiles after successful pollination.
  Abiotic factors, such as temperature, atmospheric  concentration, hydric stress, and soil nutrient status also impact the regulation of floral scent. For instance, increased temperatures in the environment can increase the emission of VOCs in flowers, potentially altering communication between plants and pollinators.
  Finally, biotic interactions may also affect the floral scent. Plant leaves attacked by herbivores emit new VOCs in response to the attack, the so-called herbivore-induced plant volatiles (HIPVs). Similarly, damaged flowers have a modified floral scent compared to undamaged ones. Micro-organisms present in nectar may alter floral scent emissions as well.