Maternal Effects of Drought Stress and

Increased inbreeding and environmental stress are two factors that may significantly affect plant population persistence in the future. However, little is known about the way in which maternal environmental and inbreeding effects combine to influence progeny. We conducted a greenhouse experiment with genetic lines from two populations, differing in inbreeding history and in soil moisture, of the herbaceous annual Impatiens capensis (Balsaminaceae) to determine the effects of maternal drought stress and inbreeding on progeny fitness traits, physiology, and response to drought stress. Significant maternal treatment effects were detected, particularly in the typically moist, highly outcrossing population. Overall, maternal drought stress reduced the fitness of progeny. Significant maternal inbreeding effects were also detected, depending on population and life-history stage. In general, inbreeding depression was not exacerbated by maternal environmental stress, but rather was apparent only when maternal environmental conditions were benign