Mirror molecules reveal drought stress in forests

(Image: Pixabay CC0) - Changes in ecosystems can be predicted more accurately via emissions of chiral compounds Worldwide, plants release about 100 million tonnes of monoterpenes into the atmosphere. These volatile organic molecules include many fragrances such as the molecule pinene, known for its fresh pine scent. Since these molecules are very reactive and can form tiny aerosol particles that can grow into condensation nuclei for raindrops, natural emissions play an important role in our climate. For climate predictions, it is therefore important to know how monoterpene emissions will change as temperatures rise. As with pinene, many monoterpenes occur in two mirror-image forms: (+) alpha-pinene and (-) alpha-pinene. Plants can release both forms of these volatile molecules directly after biosynthesis or from stores in the leaves. Because the two chiral and enantiomeric forms, respectively, have identical physical and chemical properties, they are often not considered separately in atmospheric models.