Developmental Ecology of Mayapple: Seasonal Patterns of Resource Distribution in Sexual and Vegetative Rhizome Systems

Abstract

Mayapple (Podophyllum peltatum L.), a clonal perennial herb, produces shoots that are distinctly vegetative or sexual. To determine whether shoot type was correlated with rhizome size or nutrient distribution, we compared size and N and P levels of organs of both shoot types in March, May and August. Buds, leaves and current rhizome segments were significantly larger for sexual than vegetative shoots at all sampling dates, but there was substantial overlap. Shoot types differed little in N and P concentrations, but did differ in N and P contents and in distributions of N and P among organs. N and P levels were highest in buds and green leaves; nutrient levels in rhizomes decreased from March to May but increased again by August. Rhizome size may be important for the amount of future storage capacity provided, as well as for amounts of stored carbon and/or nutrients available for release. However, rhizome size may be a consequence of bud type, rather than determining bud type, because buds are recognizably sexual or vegetative by late spring, before new rhizome growth is complete. Sexual buds may be stronger sinks for resources than are vegetative buds, leading to increased growth of their associated rhizomes. Key-words: Allocation patterns, clonal plants, developmental ecology, mayapple, nutrient distribution, plant reproduction, Podophyllum peltatum, rhizome systems