HNSE-L2-3. Post-zygotic Reproductive Isolating Barriers Contributing to Metrosideros (Myrtaceae) Divergence
Faculty Mentor: Elizabeth Stacy, Ph.D.1
1College of Sciences, Department of Life Sciences
On the Hawaiian Islands, Metrosideros (Myrtaceae) is a landscape-dominant woody species complex that includes a surprising number of interfertile varieties, races and species. These many taxa appear to represent ongoing population divergence and speciation, in which we suggest there may be postzygotic reproductive barriers relating to hybrid incompatibilities that contribute to speciation. This project examines rates of embryo development and seed germination as indicators of postzygotic isolating barriers in Hawaiian Metrosideros. We optimized laboratory methods for each measure and applied them to examine preserved seeds of pure-taxon crosses and hybrid crosses (i.e., crosses between taxa or involving F1 hybrids). After batches of seeds from both cross types are imported and rehydrated, the proportion of developed embryos is recorded under a dissecting scope. Seeds are then germinated on filter paper in a petri dish, watered and sealed with parafilm, and placed under full spectrum LED light. The proportion of seeds germinated (i.e., standing plants with two leaves) is recorded every two weeks for six weeks. This project seeks to provide insight into the role of early life-history stages in the evolution of reproductive isolating barriers in a hyper diverse, hybridizing tree species complex.
This research was funded by the Southern Nevada Northern Arizona (SNNA) Louis Stokes Alliance for Minority Participation (LSAMP), which is housed within UNLV’s Center for Academic Enrichment and Outreach and supported by a grant (HRD – 1712523) from the National Science Foundation (NSF). Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the NSF.