Seasonal Timing of Pseudoviviparous Reproduction of Leiothrix (Eriocaulaceae) Rupestrian Species in South-eastern Brazil

Abstract

Seasonal timing of pseudoviviparous reproduction can be a vital component of the successful establishment of plantlets in L. spiralis, considering that in this species the plantlets are formed only after the flower head touches the ground. In contrast, in L. vivipara, the plantlets are formed early, without touching the ground. Moreover, L. spiralis is a splitter ramet species, while L. vivipara is a canopy-forming species. The pseudoviviparous canopy-forming strategy appears to be more advantageous than the splitter ramet strategy, because even under similar soil moisture conditions, the survival of L. vivipara plantlets was greater than that of L. spiralis.

Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil

“…However, these species show differences in the frequency of vegetative and reproductive events. In L. vivipara, ramet production occurs throughout the year, while L. spiralis reproduces only once during the year (Coelho et al, 2006). Repeated reproduction (or iteroparity/ polycarpy) is a characteristic associated to predictable environments, while reproduction synchronized with favorable periods can be related both to permanent and temporary habitats.…”

“…Thus, all available resources can be allocated to pseudoviviparous reproduction. Clonal growth, specifically the pseudovivipary, is important to the maintenance of L. spiralis and L. vivipara populations (Coelho et al, 2006). Pseudovivipary is an asexual reproductive strategy, in which vegetative propagules are produced instead of sexual reproductive structures (Elmqvist and Cox, 1996).…”

“…In areas formed by dry and sandy soils, sexual reproduction becomes unfavorable because the substrate is very harsh for seed germination and seedlings establishment (Scarano, 2002). Coelho et al (2006) suggested that pseudovivipary also represents a mechanism that contributes to the survival and maintenance of L. spiralis and L. vivipara populations. The success of pseudovivipary in these environments relies on the parental care provided by the parental plant to the offspring until their establishment.…”

“…In L. vivipara in particular there is a reduction in the number of flowers per flower head and the majority of the central portion of the flower head is occupied by leaves (Giulietti et al, 1995). In L. spiralis, field observations have been unable to detect seedlings of sexual origin and it is thought that population regeneration occurs mainly through clonal propagation corresponding to the splitter-ramet strategy (Coelho et al, 2006). Low seedling recruitment in pseudoviviparous taxa is common in habitats with unfavorable conditions for seed germination and establishment (Lee and Harmer, 1980;Bauert, 1993;Miao et al, 1998).…”

“…The main attribute that plant species adapted to environments with low resource availability must have is an inherent low growth rate, even when exposed to optimal levels of resources (Rajakaruna et al, 2003). These species allocate fewer resources to growth because a higher level of supply is needed to functions that increase survival rates in adverse environments (Arendt, 1997) and so, in these rock outcrop habitats, clonal growth, specifically pseudovivipary, is important in the maintenance of L. spiralis and L. vivipara populations (Coelho et al, 2006).…”