Format: ORAL

Rebecca E. Drenovsky

John Carroll University

Gypsum soils are rich in calcium and sulfate, creating a challenge for plant life. Despite these stressful conditions, many gypsophiles (gypsum-loving plants) accumulate high levels of these mineral nutrients in their tissues, particularly in leaves, without suffering toxicity effects. Based on these patterns, we seek to investigate mechanisms, such as assimilation or sequestration, supporting excess mineral nutrient accumulation in plants growing on gypsum. Two secondary metabolites of particular interest are glucosinolates and sulfated flavonoids. These sulfur-rich metabolites are naturally present in taxa common on gypsum (glucosinolates in members of the Brassicaceae and sulfated flavonoids in members of a variety of families but particularly the Asteraceae). Our data suggest that gypsophiles may have higher glucosinolate levels than non-endemics. Similarly, we have data that suggests that plants growing on gypsum produce sulfated flavonoids in flowers and leaves and that the likelihood of their expression may be related to evolutionary history, as some taxonomic groups were more likely to produce these compounds than others. We hypothesize that glucosinolates and sulfated flavonoids may serve as sulfur sinks in gypsophiles and that glucosinolates may also support water uptake in drying soils in these taxa. Future work will investigate how widespread these patterns are in gypsophiles, as well as how plastic these responses are. Identifying the mechanisms supporting plant life on gypsum may help us understand fundamental biological processes such as speciation, adaptation, and how biotic and abiotic factors influence community assembly.