Ann Arbor Times

A recent study conducted by the University of Michigan suggests that plants in nutrient-rich soil are more likely to develop defense mechanisms against insects. The research, led by U-M scientist Mia Howard and published in Oikos, focused on goldenrod plants treated with nitrogen fertilizer over three decades.

Howard explained, “One of the exciting things about this finding is that there are so many hypotheses and theories predicting that resources would affect the evolution of plant defenses, and here we have the first experimental evidence to show that it does.”

The study was supported by several organizations including the National Science Foundation and Michigan State University. It examined how goldenrods respond to insects laying eggs in their stems. Some goldenrods "nod" their stems to prevent egg-laying, a trait linked to genetic characteristics rather than soil nutrients.

Researchers observed plots at Michigan State University's W.K. Kellogg Biological Station, where fertilized fields showed a higher concentration of nodding goldenrods compared to unfertilized ones. Howard noted that “If the plant is a nodder, it’s going to nod. It’s also really easy to phenotype because you can just look at it.”

The study highlights the value of long-term research projects for understanding plant evolution. “We were really fortunate that Kellogg biological station had started this experiment and continued to maintain it for three decades,” Howard said.