I fell in love with wild lupin (Lupinus perennis) during one of my first research experiences as a college student. I was doing a summer fellowship with the National Science Foundation at the University of Massachusetts Boston, where I was working with a lab that studied marine ecology.
The lab was interested in tracking marine mussels, which are ecologically and economically important to the New England area, by comparing the chemistry of these animals’ shells to that of the water at different coastal sites. Our field work involved donning wet suits and driving a small motor boat into the ocean to collect water samples, and at times it was bitter work. Of course, I wasn’t yet a plant biologist back then – I was trying to explore my interests rather – but I still distinctly remember being cheered up by the sight of the beautiful blueish purple flowers of wild lupin that were in bloom at several of the sampling sites we visited. And now, after gaining some botanical knowledge through my current research, I learned that there is a lot more to appreciate about this native wildflower than just its beauty.
Wild lupin has several special abilities that make it biologically interesting. For example, while it’s thought that wild lupin got its name from the Latin word for wolf (‘lupus’), because people perceived the plant’s ability to grow in poor conditions as a sign of predation, as if lupin was taking away nutrients from other plants, in reality wild lupin acts more like an ecological ally. Similar to the red clover plants I study, wild lupin actually enhances the quality of the soil it lives in by forming a symbiotic relationship with a particular kind of soil bacteria called rhizobia. In this relationship, rhizobia fix nitrogen, which is essential for plant growth, by transforming the nitrogen that’s present in the air into different forms like ammonia, nitrite and nitrate that plants can access and use to grow. This process of biological nitrogen fixation obviously benefits wild lupin directly and gives it a special advantage, but it also increases the local nitrogen content which benefits other plants.
Another interesting trait about wild lupin is its ability to ‘communicate’ with pollinators. Lupin produces a lot of protein-rich pollen that bees, especially bumblebees, are attracted to. However, if a wild lupin flower has already been visited by a bee, the center of the flower will change color from white to purple, and the bees have learned that this is a signal to avoid that flower. Basically, the flower is saying in a way: “don’t visit me, go find fresher flowers that have more pollen.” Overall, this adaptation benefits both the bee and the plant because the bee uses less energy in finding pollen and the plant increases the likelihood that its pollen gets spread around to make seeds.
As a college student trying to figure out her career path, I never would’ve guessed that the plant I stopped to admire and photograph during a summer internship would turn out to have such obvious connections to my future work studying biological nitrogen fixation and pollination ecology. What plants have you formed connections with at a young age?
“Plant database: Lupinus perennis.” Lady Bird Johnson Wildflower Center. 27 Sept. 2022. https://www.wildflower.org/plants/result.php?id_plant=lupe3
Weiss, M. R. Ecological and evolutionary significance of floral color change. 1992. University of California at Berkley, PhD dissertation.