Allozyme variability within and among populations of the epiphytic mossLeucodon (Leucodontaceae: Musci)

Abstract

Enzyme electrophoresis was used to estimate genetic variability within and among populations of five species of the genus Leucodon (L. atrovirens, L. luteus, L. nipponicus, L. sapporensis, and L. temperatus). All of these perennial, dioecious plants are epiphytic on tree trunks and produce numerous spores that are released in winter. Gene diversity within populations (HS) was low (0.070) in L. nipponicus, which grows in disturbed habitats, and high (0.169–0.202) in the other four species, which inhabit stable environments. Gene diversity between populations relative to total diversity (GST) was low in L. temperatus (0.042) and L. luteus (0.043), suggesting that extensive gene flow occurs among populations. GST was moderate in L. sapporensis (0.104) and L. atrovirens (0.114); these values are still less than those previously reported for terrestrial mosses. Since epiphytes could disperse their spores effectively by the wind, low genetic divergence among populations may be related to the epiphytic habit of the species. On the other hand, high GST value (0.208) was found in L. nipponicus. It is probably explained by the genetic differentiation of populations by genetic drift, for the species forms geographically and ecologically isolated populations with small number of individuals. We also observed incongruity between morphological and genetic similarity among species.

Genetic structure in three haploid peat mosses (Sphagnum)

“…Even though several authors claim that the gene flow potential of most bryophytes is limited (e.g. Wyatt, 1982; McQueen, 1985), many studies using indirect genetic estimation procedures have shown moderate to large numbers of migrants per generation in bryophytes (see Akiyama, 1994 for a survey). In S. angustifolium the number of migrants per generation ( M ) is greater than unity for both isozyme and RAPD markers.…”

“…show a lack of positive correlation between intra‐ and interpopulation variation. Akiyama (1994) found a similar disagreement between observed population structure and the Conocephalum – Plagiomnium model for several Leucodon species. It seems that bryophytes exhibit the same variability in population structure as other organisms.…”

Morphologically cryptic biological species within the liverwort Frullania asagrayana

“…Some studies of genetic variation in widespread species have failed to detect population structure (e.g., Cronberg et al, 1997 ;Akiyama, 1994 ;Shaw et al, 2009 ) and imply near-panmixis at the landscape and regional scales. Anthropogenic substrates are often colonized by species not present in the local environment ( Abts and Heinrichs, 1997 ;Soro et al, 1999;Miller and McDaniel, 2005 ), demonstrating effective dispersal and establishment over regional scales.…”

Genetic structure of the widespread and common Mediterranean bryophyte Pleurochaete squarrosa (Brid.) Lindb. (Pottiaceae) — evidence from nuclear and plastidic DNA sequence variation and allozymes

“…While measures we obtained are lower than most values published for liverworts, they are higher than those published for mosses based on studies covering large areas (Wyatt et al . 1992; Akiyama 1994; Cronberg et al . 1997; Cronberg 2000; Van der Velde & Bijlsma 2003; Korpelainen et al .…”