Reproductive strategies in the persistence of polymorph clover, an amphicarpic species

Abstract

Amphicarpic plants produce aerial and subterranean fruits on the same plant. Trifolium polymorphum Poir. is an amphicarpic legume that also reproduces vegetatively by regrowing storage roots. Because of this, resource allocation information for different reproductive strategies is of great interest. In this study, the production of aerial and subterranean seeds and storage roots was evaluated in populations of T. polymorphum. The Pinheiro Machado and Eldorado do Sul populations produced on average the highest (165.50) and lowest (61.87) number of inflorescences per plant, respectively. Total aerial seed production did not differ between populations. Aerial flowers produced more seeds than subterranean flowers. There were positive correlations between number of inflorescences and total aerial seeds (r = 0.73), the number of subterranean legumes and total subterranean seeds (0.94) and between number and weight of storage roots (r = 0.83). Amphicarpy associated with vegetative reproduction is an important strategy for the persistence and increase frequency of T. polymorphum in the natural pastures of the Rio Grande do Sul, where intense grazing and trampling can destroy periodically the aerial part of the plants.