Recently plant population biologists have recognized the importance of maternal effects in plants, that is, the transmission of traits from a plant to its seed offspring through means other than normal chromosomal inheritance. Drs. Schmitt and Wulff propose to investigate one such maternal effect, the effect of a plant's environment on the relative success of its offspring, in natural populations of the common lawn and pasture weed, Plantago lanceolata (ribwort plantain). By propagating clones of individual plants and planting them into different environments, then crossing them and collecting their seeds, the investigators will be able to determine how parental environment affects offspring traits such as seed size and germination rate, while controlling the genetic background of the parent across environments. By planting these seed progeny back into the same experimental sites, the investigators will be able to determine how parental environment affects offspring success. The proposed research will make several contributions to the field of plant population biology. First, it will provide unique data on the magnitude of environmental maternal effects generated by environmental heterogeneity within and between natural populations. Second, this will be the first study to investigate the impact of environmental maternal effects on offspring fitness under natural conditions. The findings will be important both for studies of plant population dynamics and seed demography and for understanding the evolution of seed and seedling traits within natural populations. This work will also have implications for applied plant biology because Plantago lanceolata is a common weed and because environmental maternal effects are undoubtedly important in many crop species.
