ABSTRACT
The major purpose of this study was to determine the chemical relationships between liverwort species belonging to the Lejeuneaceae family on the basis of sesqui- and diterpenoid composition. GC/MS analysis of the 31 liverwort specimens belonging to the Lejeuneaceae family indicated variability of the chemical composition of terpenoids depending on liverwort species. Each of the analyzed liverworts is characterized by the presence of particular compounds. However, there are some characteristic components, which can be chemical markers of this liverwort family. These are the pinguisane and monocyclofarnesane type sesquiterpenoids, the fusicoccane type diterpenoids, and also the sesquiterpene hydrocarbon, isolepidozene. Chemical data also showed the differences among liverworts classified in the two subfamilies, the Ptychanthoideae and Lejeuneoideae. All of the mentioned characteristic components are present in species of the subfamily Ptychanthoideae. On the other hand, among the characteristic components, only beta-pinguisene was detected in Cololejeunea stotleriana, Colura irrorata, and Myriocoleopsis gymnocolea classified in the subfamily Lejeuneoideae (subtribe Cololejeuneinae). The latter component was found to be a marker for members of the subtribe Cololejeuneinae. Neither isolepidozene nor the pinguisanes, fusicoccanes and monocyclofarnesanes were found in Lejeunea topoensis (subfamily Lejeuneoideae). The existence of the chemical polymorphism between both subfamilies is also evident from PCA analysis.
Subject(s)
Hepatophyta/chemistry , Gas Chromatography-Mass SpectrometryABSTRACT
⢠Shifts in sexual systems are among the most common and important transitions in plants and are correlated with a suite of life-history traits. The evolution of sexual systems and their relationships to gametophyte size, sexual and asexual reproduction, and epiphytism are examined here in the liverwort genus Radula. ⢠The sequence of trait acquisition and the phylogenetic correlations between those traits was investigated using comparative methods. ⢠Shifts in sexual systems recurrently occurred from dioecy to monoecy within facultative epiphyte lineages. Production of specialized asexual gemmae was correlated to neither dioecy nor strict epiphytism. ⢠The significant correlations among life-history traits related to sexual systems and habitat conditions suggest the existence of evolutionary trade-offs. Obligate epiphytes do not produce gemmae more frequently than facultative epiphytes and disperse by whole gametophyte fragments, presumably to avoid the sensitive protonemal stage in a habitat prone to rapid changes in moisture availability. As dispersal ranges correlate with diaspore size, this reinforces the notion that epiphytes experience strong dispersal limitations. Our results thus provide the evolutionary complement to metapopulation, metacommunity and experimental studies demonstrating trade-offs between dispersal distance, establishment ability, and life-history strategy, which may be central to the evolution of reproductive strategies in bryophytes.