Amplification of noncoding chloroplast DNA for phylogenetic studies in lycophytes and monilophytes with a comparative example of relative phylogenetic utility from Ophioglossaceae

Noncoding DNA sequences from numerous regions of the chloroplast genome have provided a significant source of characters for phylogenetic studies in seed plants. In lycophytes and monilophytes (leptosporangiate ferns, eusporangiate ferns, Psilotaceae, and Equisetaceae), on the other hand, relatively few noncoding chloroplast DNA regions have been explored. We screened 30 lycophyte and monilophyte species to determine the potential utility of PCR amplification primers for 18 noncoding chloroplast DNA regions that have previously been used in seed plant studies. Of these primer sets eight appear to be nearly universally capable of amplifying lycophyte and monilophyte DNAs, and an additional six are useful in at least some groups. To further explore the application of noncoding chloroplast DNA, we analyzed the relative phylogenetic utility of five cpDNA regions for resolving relationships in Botrychium s.l. (Ophioglossaceae). Previous studies have evaluated both the gene rbcL and the trnL(UAA)-trnF(GAA) intergenic spacer in this group. To these published data we added sequences of the trnS(GCU)-trnG(UUC) intergenic spacer + the trnG(UUC) intron region, the trnS(GGA)-rpS4 intergenic spacer+rpS4 gene, and the rpL16 intron. Both the trnS(GCU)-trnG(UUC) and rpL16 regions are highly variable in angiosperms and the trnS(GGA)-rpS4 region has been widely used in monilophyte phylogenetic studies. Phylogenetic resolution was equivalent across regions, but the strength of support for the phylogenies varied among regions. Of the five sampled regions the trnS(GCU)-trnG(UUC) spacer+trnG(UUC) intron region provided the strongest support for the inferred phylogeny.     

Causes and consequences of high osmotic potentials in epiphytic higher plants

Past reports of the water relations of epiphytes, particularly bromeliads, indicate that tissue osmotic potentials in these tropical and subtropical plants are very high (close to zero) and are similar to values for aquatic plants. This is puzzling because several ecophysiological studies have revealed a high degree of drought stress tolerance in some of these epiphytes. The goal of this study was two-fold: (1) to increase the number of epiphytic taxa sampled for tissue osmotic potentials; and (2) to explain the apparent discrepancy in the significance of the tissue water relations and tolerance of drought stress in epiphytes. Tissue osmotic potentials of 30 species of epiphytic ferns, lycophytes, and orchids were measured in a subtropical rain forest in northeastern Taiwan. Nearly all values were less negative than -1.0 MPa, in line with all previous data for epiphytes. It is argued that such high osmotic potentials, indicative of low solute concentrations, are the result of environmental constraints of the epiphytic habitat on productivity of these plants, and that low rates of photosynthesis and transpiration delay the onset of turgor loss in the tissues of epiphytes such that they appear to be very drought-stress tolerant. Maintenance of photosynthetic activity long into drought periods is ascribed to low rates of transpiration and, hence, delayed tissue desiccation, and hydration of the photosynthetic tissue at the expense of water from the water-storage parenchyma.     

Paleo-polyploidization in Lycophytes

Lycophytes and seed plants constitute the typical vascular plants. Lycophytes have been thought to have no paleo-polyploidization although the event is known to be critical for the fast expansion of seed plants. Here, genomic analyses including the homologous gene dot plot analysis detected multiple paleo-polyploidization events, with one occurring approximately 13–15 million years ago (MYA) and another about 125–142 MYA, during the evolution of the genome of Selaginella moellendorffii, a model lycophyte. In addition, comparative analysis of reconstructed ancestral genomes of lycophytes and angiosperms suggested that lycophytes were affected by more paleo-polyploidization events than seed plants. Results from the present genomic analyses indicate that paleo-polyploidization has contributed to the successful establishment of both lineages—lycophytes and seed plants—of vascular plants.     

The Exploitation and Utilization of Lycophyte and Fern Resources in Xishuangbanna,Yunnan

Xishuangbanna lies in the south of Yunnan. The composition and distributive regulation of lycophytes and ferns in Xishuangbanna are studied in this paper. As a result, 363 species of wild lycophytes and ferns which belong to 76 genera and 31 families are found in this area. The six species rich families are Polypodiaceae, Athyriaceae, Thelypteridaceae, Aspleniaceae, Pteridaceae and Selaginellaceae. The geographical distribution of the species shows that this flora mainly consists of Tropical Asia elements. Terrestrial species are the richest of this flora, followed by epiphytic and lithophytic species. The lycophytes and ferns resources of Xishuangbanna are abundant. However, the exploitation and utilization of this group of plants are ignored. This study investigated lycophytes and ferns resources of Xishuangbanna. Medicinal, edible and ornamental ferns in Xishuangbanna have been clearly researched and their utilization and protection have been discussed.     

Characterization of the <Emphasis Type="Italic">Selaginella remotifolia</Emphasis> MADS-box gene

Recent progress in plant molecular genetics has revealed that floral organ development is regulated by several homeotic selector genes, most of which belong to the MADS-box gene family. Here we report on SrMADS1, a MIKC^c-type MADS-box gene from Selaginella, a spikemoss belonging to the lycophytes. SrMADS1 phylogenetically forms a monophyletic clade with genes of the LAMB2 group, which are MIKC^c genes of the clubmoss Lycopodium, and is expressed in whole sporophytic tissues except roots and rhizophores. Our results and the previous report on Lycopodium MIKC^c genes suggest that the ancestral MIKC^c gene of primitive dichotomous plants in the early Devonian was involved in the development of basic sporophytic tissues such as shoot, stem, and sporangium. Electronic Publication     

石松类和蕨类植物的主要分类系统的科属比较

石松类和蕨类植物在秦仁昌（1978）系统、《中国蕨类植物科属志》、《中国植物志》、Christenhusz维管植物线性排列系统中和“FloraofChina”的科属组成、数量存在很大差异。秦仁昌（1978）系统收录63科223属,《中国蕨类植物科属志》63科226属,《中国植物志》61科220属、Chnstenhusz线性排列系统38科163属和“FloraofChina”38科177属。本文通过比较石松类和蕨类植物的几个主要分类系统中科属的变动情况,拟为新一代植物志（iFlora）中石松类和蕨类植物的编研提供依据。同时,还指出了几个主要的分类系统中关于中文名、拉丁名以及命名人的不一致和错误．为进一步研究提供检索和鉴定参考。     

Synthèse sur la flore des nodules du Lagerstätte de Montceau-les-Mines (Carbonifère supérieur,France)

The flora from the Montceau-les-Mines Lagerstätte (Late Pennsylvanian, Stephanian, France) is preserved in small sideritic nodules and was studied in three locations in the (1) Saint-Louis, (2) Saint-François, and (3) Sainte-Hélène opencast mines. Qualitative and quantitative analyses of plant diversity and floristic composition in about 7000 nodules indicate substantial variations in the floral composition of these opencast mines. More than 50 taxa are recognized and belong to groups typical of the Late Carboniferous flora (lycopsids, sphenopsids, tree ferns, and pteridosperms). Arborescent sphenopsids and tree ferns were the major components at Saint-Louis, whereas the flora from Saint-François consisted mainly of pteridosperms; the one from Sainte-Hélène has a more balanced composition. Taphonomic and sedimentological data show that the flora contained in the nodules was hypoautochthonous to parautochthonous. The Montceau Basin displayed a mosaic of paleoenvironments (e.g., deltaic lacustrine, paludal to fluvial) which favored colonization by plants and animals.