Effects of population site and maternal drought on establishment physiology inImpatiens capensismeerb. (Balsaminaceae)

Populations of Impatiens capensis can differentiate across a range of soil moisture conditions. Differences in the plasticity of drought response at both the physiological and morphological level have been documented in populations across the North American range of this species. Impatiens populations tend to utilize whichever drought response mechanism will be most helpful in ensuring their survival and persistence in their particular environment. Here, we examine whether populations from a range of moisture environments exhibit tolerance/avoidance strategies in early life-history and whether maternal effects are important to seedling stress responses. Populations from Pennsylvania across a range of three moisture conditions all responded to maternal drought by decreasing stomatal conductance in seedlings; this maternal drought response was ephemeral and only observed during the first few weeks of growth. Moreover, abscisic acid content covaried with this conductance plasticity for two of the three populations. For the population with the greatest amount of soil moisture, abscisic acid sensitivity seemed to be more important for maternal drought response.