Klemow, Kenneth M. and Darcy J. Broody. 1989. REPRODUCTION IN ECHIUM VULGARE L. (BLUEWEED): EFFECTS OF SEED POSITION AND SEED WEIGHT ON SEEDLING GROWTH. Contributed paper: Ecological Society of America meeting. Abstract: Bulletin of the Ecological Society of America 70:171.
We examined seed production and early seedling growth for Echium vulgare, a facultative-biennial herb that has an erect main axis and numerous lateral branches, each bearing 2-50 flowers. We wanted to determine whether seeds formed in proximal flowers were larger than those that formed in distal flowers, and, if so, whether those larger seeds produced larger seedlings. Seeds were collected from five plants growing near Wilkes-Barre, PA, noting their position on the parent. Each seed was weighed, placed on top of sterilized soil, and watered daily. The date of emergence and the growth of each seedling was recorded for six weeks. Seeds from proximal flowers proved to be significantly larger than those from distal flowers (2.4 vs 1.7 mg; P<0.01). Moreover, seeds from proximal flowers tended to produce larger seedlings (r2 = 0.21; P<0.01). Seed position therefore did have an effect, although weak, on subsequent seedling growth. However, much of the variation in seedling growth remains unexplained, despite nearly uniform conditions with no competition. We therefore postulate that other factors, perhaps innate (genetic), influence seedling size in this species.