Student Research at the Arnold Arboretum

Posted by Chase Mason

At the Arnold Arboretum, three Boston University seniors are midway through a variety of new research projects at the intersection of plant physiology, ecology, genetics, and evolution. Sponsored by BU Professor Richard Primack, undergraduates Juliana Webber, Luca Russo, and Tessa Pliakas are set to begin their second semester of research with Arboretum scientist and Putnam Fellow Chase Mason.

Since September, Juliana has been examining the evolution of leaf flavonoids and other phenolics across diverse wild sunflowers (genus Helianthus) from across North America. Her results indicate large variation in secondary chemistry across wild sunflowers, and will improve our understanding of how allocation to defensive chemistry varies in response to plant adaptation to local soil and climate conditions.

At the same time, both Juliana and Luca have been examining the response of cultivated sunflower (Helianthus annuus) to hormonally-simulated insect attack. Juliana and Luca have been tracking how activating this internal plant defense response affects sunflower allocation to growth and reproduction, and leaf palatability to snails, grasshoppers, and caterpillars. In the coming months they will be examining in detail which classes of chemical defenses were most upregulated by defense induction, and together these multiple angles will tell us a great deal about trade-offs between growth, defense, and reproduction in an important oilseed crop.

In the lab, Tessa has been examining the carotenoid content of nearly a thousand samples of frozen sunflower petals, in an attempt to understand the genetic basis of flower color in cultivated sunflower. By assessing pigment concentration across an association mapping panel of several hundred sequenced sunflower lines, Tessa will begin the new year by mapping variation in petal carotenoid content to the sunflower genome, in order to describe the genetic architecture of this trait and begin the hunt for the candidate genes that determine whether sunflower petals are faint yellow, bright orange, or somewhere in between.

You can read more about Dr. Mason’s research and keep up to date on developments here.