Genetic and environmental contributions to variation in leaf mono- and sesquiterpenes of Heterotheca subaxillaris

Abstract Field and greenhouse experiments were performed to measure genetic and environmental contributions to variation in the leaf mono- and sesquiterpenes of Heterotheca subaxillaris . Under greenhouse conditions, plants from a nitratevariable habitat (abandoned peach orchard) exhibit greater phenotypic variation in response to nitrate availability than plants from a continuously nitrate-poor environment (coastal sand dune). A genetic contribution to variation in volatile terpenes was measured only in the nitrate-variable orchard habitat. These results suggest that the magnitude of both genetic variation and phenotypic plasticity in volatile terpene production can differ between populations and may increase with greater environmental heterogeniety in the resources which affect terpene metabolism.