Night Scents. ‘Petunias don’t wear watches, yet certain petunia species emit their floral fragrance as if they did. Just before dusk, they begin producing scent and continue fragrance output throughout the night. At dawn, they shut down scent production, becoming virtually scent-free during the day.’
Similar enzymes, different smells. ‘Petunia flowers and basil leaves use similar enzymes to give the plants their fragrance, say biologists in the US. The enzymes also give spices, such as cloves and cinnamon, their spice.
Enzymes from petunia petals and basil-leaf glands both react with coniferyl acetate to make eugenol (in basil) and isoeugenol (in petunias), according to Eran Pichersky, from the University of Michigan. Pichersky identified the enzymes, their genes and the reaction pathway they trigger.
The eugenols are phenylpropenes, many of which have antimicrobial properties and attractive aromas and fragrances. ‘These compounds have been used for millennia by humans, so finally finding out how they are made is satisfying,’ Pichersky told Chemistry World.’