Trifolium polymorphum: an amphicarpic species with an interesting reproductive biology

• Published in: Revista brasileira de botânica 2019-12, Vol.42 (4), p.681-687
• Main Authors: Conterato, Ionara Fátima, de Oliveira, Paula Juliane Barbosa, de David, Diego Bitencourt, da Trindade, Júlio Kuhn, Schifino-Wittmann, Maria Teresa, Maldaner, Joseila, Agnol, Miguel Dall, Nunes, João Rodolfo Guimarães
• Format: Article
• Language: English
• Subjects: Asexual reproduction; Biology; Biomedical and Life Sciences; Botany; Endemic species; Flowers; Herbivory; Life Sciences; Original Article; Pasture; Plant reproduction; Plant Systematics/Taxonomy/Biogeography; Plants (botany); Regeneration; Regrowth; Reproduction; Reproduction (biology); Reproductive strategy; Roots; Seeds; Sexual reproduction; Storage; Trampling; Trifolium polymorphum
• ISSN: 0100-8404; 1806-9959
• DOI: 10.1007/s40415-019-00570-x

An interesting aspect of the biology of Trifolium polymorphum , an endemic species of the natural pastures of Rio Grande do Sul State in Brazil, is that it is amphicarpic. Amphicarpy is a fascinating reproductive strategy in which aerial and subterranean seeds are produced by the same plant. We evaluated the number, size and weight of aerial and subterranean seeds of two populations (Bagé and Santana do Livramento) of T. polymorphum which have grown from the regrowth of storage roots and in the absence of herbivory. Aerial flowers produced more seeds than subterranean flowers, about 14 times in the Santana do Livramento population and nine times in the Bagé population. However subterranean seeds were heavier than aerial seeds. We suggest that in the natural pastures of Rio Grande do Sul, where intense grazing and trampling can periodically destroy the aerial part of the plants, the occasional formation of subterranean seeds in T. polymorphum provides an alternative safety system in terms of population persistence. Although amphicarpic, T. polymorphum invests early in asexual reproduction through the production of storage roots, which favors the persistence in unfavorable habitats for sexual reproduction, and thus plants may persist vegetatively year after year without the need of regeneration by seeds.