Bryophyte diaspore bank: a genetic memory? Genetic structure and genetic diversity of surface populations and diaspore bank in the liverwort Mannia fragrans (Aytoniaceae)

Abstract

Propagule banks are assumed to be able to store considerable genetic variability. Bryophyte populations are expected to rely more heavily on stored propagules than those of seed plants due to the vulnerability of the haploid gametophyte. This reliance has important implications for the genetic structure and evolutionary potential of surface populations. A liverwort, Mannia fragrans, was used to test whether the bryophyte diaspore bank functions as a "genetic memory." If a diaspore bank is capable of conserving genetic variability over generations, the levels of genetic diversity in the soil are expected to be similar or higher than at the surface. Surface and diaspore bank constituents of two populations of M. fragrans were investigated. Genetic structure and diversity measured as unbiased heterozygosity were analyzed using three ISSR markers. Similar genetic diversities were found in the soil (H(s) = 0.067) and at the surface (H(s)= 0.082). However, more haplotypes and specific haplotype lineages were present in soil samples. The results suggest that the bryophyte diaspore bank has an important role in accumulating genetic variability over generations and seasons. It is postulated that the role of the diaspore bank as a "genetic memory" is especially important in species of temporarily available habitats that have long-lived spores and genetically variable populations.

Environmental drivers of the bryophyte propagule bank and its comparison with forest-floor assemblage in Central European temperate mixed forests

“…Contrary to our results, it has been shown that the diaspore bank can have similar or higher diversity than the actual forest-floor, both in temperate forests and grasslands (Jonsson, 1993;Hock, 2007;Hock et al, 2008;Vanderpoorten & Goffinet, 2009). In tropical rain forests, a similarly species poor diaspore bank was observed, because of the inhibitory effect of the litter layer (Maciel-Silva et al, 2012).…”

“…Most studies have demonstrated that the diaspore bank has similar or greater diversity than the aboveground vegetation (Jonsson, 1993;Rydgren & Hestmark, 1997;Hock et al, 2008). In addition to the aforementioned importance in bryophyte diversity, the role of the bryophyte propagule bank is diverse: ensuring the survival of bryophytes under unfavourable conditions and after disturbance, facilitating regeneration and colonization, and regulating population size (Van Tooren et al, 1990;Jonsson, 1993;Lloret, 1994;During, 1995During, , 1997Hock et al, 2008;Caners et al, 2009;Vanderpoorten & Goffinet, 2009).…”

“…In addition to the aforementioned importance in bryophyte diversity, the role of the bryophyte propagule bank is diverse: ensuring the survival of bryophytes under unfavourable conditions and after disturbance, facilitating regeneration and colonization, and regulating population size (Van Tooren et al, 1990;Jonsson, 1993;Lloret, 1994;During, 1995During, , 1997Hock et al, 2008;Caners et al, 2009;Vanderpoorten & Goffinet, 2009). While for phanerogams many types of dormancy and dormancy-breaking mechanisms have been described, in the case of bryophyte propagules, knowledge is sparse (Sundberg & Rydin, 2000;During, 2001;Hock et al, 2004).…”

Moss Propagules Banks in a Secondary Subtropical Moist Forest in Puerto Rico: A First Description

“…This temporal suitability for some species should provide enough time for their reproduction and dispersal of their progeny unto other soils banks or substrate that allows their "immediate" germination. Genetic material from these propagules at that specific depth may be the factor that aid in these modules survival or fitness [2]. If they fail to reproduce and disperse, then other species would take over and diminish the current moss population and favor another, thus creating a dynamic competition environment.…”

“…These banks function as a reservoir of previous generation genetic material [2], which could be produced by spores or/and asexual propagules (i.e. gametophyte fragments, gemmae, etc.).…”