The Gardens on Spring Creek

By Andrew Scott, Horticulturist for The Gardens on Spring Creek This is the second installment of a two-part feature on plant defenses. Read Part I online at North Forty News . Caffeine, nicotine, morphine, cocaine ... sounds like the ingredients label on an old-timey cold medicine, right? These molecules are actually all alkaloids, some of the most common chemical deterrents deployed by plants. As the adage goes, the dose makes the poison. While people can (and do) ingest these alkaloids for their psychoactive effects, they prove to be much more deadly to a small insect that weighs all but a few tenths of a milligram.  The sap of opium poppies ( Papaver somniferum ) contains morphine, a potent sedative (via Daniel Prudek , Hodder Education Magazines)   Still, alkaloids have a strongly bitter taste, which animals have learned to associate with the toxic effects they can have. Eating green potatoes isn’t likely to kill you, but solanine, the alkaloid that triggers this change...