Reproductive allocation in rhizomatous, seminiferous, and pseudoviviparous Leiothrix (Eriocaulaceae) species

摘要

Pseudoviviparous species are considered to rely almost entirely on vegetative propagation, because flowers are replaced by sprouts, and seedling recruitment is rare. We compared reproductive allocation (inflorescence and seed production) in three propagation modes presented by sympatric species of Leiothrix (Eriocaulaceae): rhizomatous and seminiferous (RS-L. crassifolia); rhizomatous, seminiferous, and pseudoviviparous (RSP-L. spiralis); and seminiferous and pseudoviviparous, in which seed production is considered rare due to reduced inflorescence size and small number of pistillate flowers (SP-L. arrecta and L. propinqua). We hypothesize that such propagation modes constitute a continuum of reproductive investment, that is: RS > RSP > SP. We harvested 154 Leiothrix spp. individuals at the Serra do Cip, SE Brazil, from which we recorded the number of capitula and seeds, mean seed weight, and dry biomass allocated to plant structures. We then compared distinct propagation modes in relation to reproductive allocation, inflorescence-based and seed-based reproductive effort, and biomass partitioning. Contrary to expectations, the reproductive investment hierarchy found was SP a parts per thousand yen RS > RSP. Our results do not fully concur with the current view that pseudoviviparous plants allocate few resources to reproduction. We suggest that the larger reproductive investment observed in SP helps to wait for better recruitment conditions in crowded and highly competitive mature populations (temporal escape), and to cope with destructive disturbances such as fire, since SP species lacks rhizomes