Poison Ivy vs Fungus
ambience: dawn Chorus
Poison Ivy is one of those plants that seem to be everywhere you don’t want them to be. So you might think researchers studying poison ivy would have an easy time growing it. Not quite. I’m Jim Metzner and this is the Pulse of the Planet.
Jelesko: One of the first things we tried to do was just germinated the seedling the seeds that we collected, and that turned out to be astonishingly more of a challenge than we thought.
John Jelesko is an associate Professor in the Department of Plant Pathology, Physiology, and Weed Science at Virginia Tech
Jelesko: If we just put poison ivy between paper towels in a jar or something like that, the seeds would never germinate. Worse yet, if the few seeds that would germinate, oftentimes, would die very quickly because they were overwhelmed by a fungus, and that it would kill the seedlings.
So the question was, why would poison ivy evolve to have this association with a fungus that wants to kill its seedlings?
Jelesko: What we think is that if poison ivy seeds happen to just land on the ground, there’ll be many seedlings that are there together, and if they all germinate close to the mother plant, they’ll all be fighting for the same resources. And what we think the benefit of harboring this pathogenic fungus for seedlings is that those seedlings will, basically, not survive because the fungus will overwhelm them.
Even without the fungus, it’s still hard to grow poison ivy.
Jelesko: In our very earliest studies, we were just trying to get poison ivy seeds to germinate, when we put poison ivy seeds on a media that should be very permissive for them to germinate, we found that they did not germinate.
Unless the growing medium is acidic. So here’s the mystery: what spreads poison ivy by both killing the fungus and providing an acidic environment for its seeds? We’ll find out in our next program I’m Jim Metzner and this is the Pulse of the Planet.