Differences in Seedling Ecophysiology and Reproductive Strategy in Two  Impatiens  capensis Ecotypes

Impatienscapensisis a weedy annual plant that grows contiguouslyfrom the Eastern U.S. to the Rocky Mountains through a range of soil conditions, from the moist habitats of the Eastern U.S. to very dry habitats in the West. In this study, weassess differences in the morphology, physiology, and phenologyof Impatienslines from PA and CO. It is these differences that allow I. capensisto survive in such a wide range of conditions and form ecotypes. Previous study of these ecotypes has focused on later life-history stages; here, we examine seedling traits in greenhouse conditions. Measurements of stomatal conductance, photosystem efficiency, stomatal density, chlorophyll content index and seedling height differed between CO and PA ecotypes. Because we used inbred lines for this study, we calculated heritability for these seedling traits and considered the evolutionary potential of these populations at an early life-history stage. Furthermore, differences in seed weight and germination time, when contextualized by morphological and physiological data, provide insight into survival and reproductive strategies for these ecotypes.