Environmentally induced carry-over effects on seed production, germination and seedling performance in Bunium bulbocastanum (Apiaceae)

Abstract

This study investigates the effects of differences in resource supply to parent plants on seed production, seed germination and seedling performance in the tuber-forming geophyte Bunium bulbocastanum L. (Apiaceae). Parent plants were grown in a factorial design with two levels of light and nutrient supply, respectively. All plants flowered and set seeds in the second growing season. For each treatment, seeds were split into three weight classes and 100 seeds of each group (3 weight classes × 4 treatments) were planted. The emerging seedling were grown under uniform conditions for one growing season. Resource availability strongly affected the number, but not the size of seeds produced. Nevertheless, seeds of equal size originating from different maternal light and nutrient treatments showed marked differences in germination rate, seedling performance and final tuber weight, indicating the presence of environmentally induced carry-over effects in B. bulbocastanum . Shading of parent plants had generally negative effects on offspring performance, while low nutrient supply tended to increase germination and seedling growth. Environmental carry-over effects influenced final tuber weight via seedling characteristics in a complex way, thereby impeding clear predictions of offspring performance from seed size alone.