Making scent molecules is a resource-heavy endeavor for a plant. It makes evolutionary sense for a flower to be able to husband its resources when necessary. And now it appears they can.
Working at the Hebrew University’s Faculty of Agriculture, Can’ani discovered that petunias grown in conditions of warmer than optimal temperature make significantly less perfume, he explains in his paper “Petunia × hybrida floral scent production is negatively affected by high-temperature growth conditions,” published in the journal Plant, Cell & Environment.
— Read more at Yet Another Casualty of Global Warming: Petunia Perfume at Haaretz.