My first date with Piper urostachyum

 By Anna Wassel

Just like we all have a mental list (conscious or subconscious) of things we look for in a romantic significant other, my research partner, Emily, and I had a list of qualities that we wanted in our model species for our independent project.  After all, we knew we were probably going to be spending more time with this plant than talking to our boyfriends in the upcoming week, so it would help if we liked it. 

We were looking for a plant that was common in the forest, had trichomes, and was easy to identify, so as to not confuse it with a different species when we went out to sample.  Orlando, La Selva’s resident plant expert, introduced us to some of the eligible Piper species around the station.  The first Piper was nice enough, but not really our type.  And then we saw it: Piper urostachyum.  It’s long, white trichomes and unique pendant inflorescence really swept us off our botanical feet.  We arranged to have a first date the next day with this plant to see if it was really cut out to spend a week with Emily and I, very selective scientists with high standards.

The next day, we collected some leaves from several plants.  We brought the leaves back to the classroom to test how we could count the density of trichomes on each plant.  It essentially became a spa day; we painted clear nail polish on the front and back surfaces of the leaf to see if we could peel the trichomes off in order to investigate them under a microscope, but the trichomes were attached too strongly and thickly to the plant to be peeled off by nail polish.  Then the Piper leaves got a waxing; by using tape to gently peel off the epiphylls and as many trichomes as possible, it would leave stumps on the surface of the leaf that were more easily picked up by the nailpolish.  However, this didn’t work very well, either. This was a little bit tricky. Our first date was off to a rough start. We needed Piper urostachyum to open up to us and share more about its life if this relationship was ever going to work out.

We then discovered that the old-fashioned, traditional method of simply counting the trichomes still on the plant under the microscope-- while visually overwhelming at times-- was the best way to count the density of trichomes on Piper urostachyum.  Perhaps there was hope, after all.  We did discover, though, that P. urostachyum had some skeletons in its closet, or rather some bugs in its domatia.  Domatia can be small pockets in leaves, either made from trichomes or leaf tissue, that bugs live in as part of a symbiotic relationship.  This would make things a little more complicated for Emily and me, but we were up for complicated. We decided Piper urostachyum was a good match for us, and we were on our way. 

We spent the next week investigating if Piper urostachyum changes its trichome density as a defense to herbivory in response to previous damage from herbivores or increased light availability.  It was hours hiking in the rain, hours counting trichomes (36,000+ trichomes, actually), hours analyzing our data, and I have to say, I would do it all again.  Though we did not find a statistically significant relationship of trichomes increasing density in response to herbivory or light, the relationship that Emily and I had with Piper urostachyum will always hold a significant place in our hearts.