Genus Juncus Research Articles

A revision of the Juncaceae with delimitation of six new genera: nomenclatural changes in Juncus

Phylogenetic relationships within the genus Juncus L. remained poorly understood for most groups, and the taxonomic division to two subgenera and ten sections was rather pragmatic. The taxonomic treatment based on the morphology of this group is complicated due to numerous repeated reductions. Continuing the molecular phylogenetic, taxonomic, and nomenclatural studies of the Juncaceae, we propose a nomenclatural revision of Juncus and propose 379 new combinations for six newly recognized genera based on combined morphological and molecular data support: Verojuncus Záveská Drábková & Proćków, Juncinella (Fourr. ex V.I.Krecz. & Gontsch.) Záveská Drábková & Proćków, Alpinojuncus Záveská Drábková & Proćków, Australojuncus Záveská Drábková & Proćków, Boreojuncus Záveská Drábková & Proćków, and Agathryon (Raf.) Záveská Drábková & Proćków.

Repeat-based phylogenomics shed light on unclear relationships in the monocentric genus Juncus L. (Juncaceae)

The repetitive fraction (repeatome) of eukaryotic genomes is diverse and usually fast evolving, being an important tool for clarify plant systematics. The genus Juncus L. comprises 332 species, karyotypically recognized by having holocentric chromosomes. However, four species were recently described as monocentric, yet our understanding of their genome evolution is largely masked by unclear phylogenetic relationships. Here, we reassess the current Juncus systematics using low-coverage genome skimming data of 33 taxa to construct repeats, nuclear rDNA and plastome-based phylogenetic hypothesis. Furthermore, we characterize the repeatome and chromosomal distribution of Juncus-specific centromeric repeats/CENH3 protein to test the monocentricity reach in the genus. Repeat-base phylogenies revealed topologies congruent with the rDNA tree, but not with the plastome tree. The incongruence between nuclear and plastome chloroplast dataset suggest an ancient hybridization in the divergence of Juncotypus and Tenageia sections 40 Myr ago. The phylogenetic resolution at section level was better fitted with the rDNA/repeat-based approaches, with the recognition of two monophyletic sections (Stygiopsis and Tenageia). We found specific repeatome trends for the main lineages, such as the higher abundances of TEs in the Caespitosi and Iridifolii + Ozophyllum clades. CENH3 immunostaining confirmed the monocentricity of Juncus, which can be a generic synapomorphy for the genus. The heterogeneity of the repeatomes, with high phylogenetic informativeness, identified here may be correlated with their ancient origin (56 Mya) and reveals the potential of comparative genomic analyses for understanding plant systematics and evolution.

Toward finally unraveling the phylogenetic relationships of Juncaceae with respect to another cyperid family, Cyperaceae

Juncaceae is a cosmopolitan family belonging to the cyperid clade of Poales together with Cyperaceae and Thurniaceae. These families have global economic and ethnobotanical significance and are often keystone species in wetlands around the world, with a widespread cosmopolitan distribution in temperate and arctic regions in both hemispheres. Currently, Juncaceae comprises more than 474 species in eight genera: Distichia, Juncus, Luzula, Marsippospermum, Oreojuncus, Oxychloë, Patosia and Rostkovia. The phylogeny of cyperids has not been studied before in a complex view based on most sequenced species from all three families. In this study, most sequenced regions from chloroplast (rbcL, trnL, trnL-trnF) and nuclear (ITS1-5.8S-ITS2) genomes were employed from more than a thousand species of cyperids covering all infrageneric groups from their entire distributional range. We analyzed them by maximum parsimony, maximum likelihood, and Bayesian inference to revise the phylogenetic relationships in Juncaceae and Cyperaceae. Our major results include the delimitation of the most problematic paraphyletic genus Juncus, in which six new genera are recognized and proposed to recover monophyly in this group: Juncus, Verojuncus, gen. nov., Juncinella, gen. et stat. nov., Alpinojuncus, gen. nov., Australojuncus, gen. nov., Boreojuncus, gen. nov. and Agathryon, gen. et stat. nov. For these genera, a new category, Juncus supragen. et stat. nov., was established. This new classification places most groups recognized within the formal Juncus clade into natural genera that are supported by morphological characters.

Typification of four Linnaean names in the genus Juncus (Juncaceae)

AbstractThe lectotypification of four Linnaean names in the genus Juncus: J. articulatus, J. inflexus, J. pilosus (≡ Luzula pilosa) and J. stygius is discussed. The designation of the nomenclatural types is based on the consultation of Linnaeus's original material and the literature cited in the respective protologues. The names are lectotypified using specimens from LINN and L (Adriaan van Royen Herbarium), and a Morison illustration for the name J. inflexus. Furthermore, an epitype is designated for J. inflexus due to ambiguity in the interpretation of the lectotype.

Aktuálne rozšírenie vybraných ohrozených a vzácnych taxónov rodu Juncus L. na Slovensku a možnosti ich ochrany

Aktuálne rozšírenie vybraných ohrozených a vzácnych taxónov rodu Juncus L. na Slovensku a možnosti ich ochrany

Antioxidant responses under salinity and drought in three closely related wild monocots with different ecological optima.

Some deleterious effects of drought, soil salinity and other abiotic stresses are mediated by the generation of oxidative stress through an increase in reactive oxygen species (ROS) that damage cellular membranes, proteins and DNA. In response to increased ROS, plants activate an array of enzymatic and non-enzymatic antioxidant defences. We have correlated the activation of these responses with the contrasting tolerance to salinity and drought of three species of the genus Juncus, viz. J. maritimus, J. acutus (both halophytes) and J. articulatus (salt-sensitive). Both stresses were given for 8 weeks to 6-week-old seedlings in a controlled environment chamber. Each stress inhibited growth and degraded photosynthetic pigments in the three species with the most pronounced effects being in J. articulatus. Salt and water stress also generated oxidative stress in all three taxa with J. articulatus being the most affected in terms of accumulation of malondialdehyde (a reliable oxidative stress marker). The apparent lower oxidative stress in halophytic J. maritimus and J. acutus compared with salt-sensitive J. articulatus is explained by a more efficient activation of antioxidant systems since salt or water deficiency induced a stronger accumulation of antioxidant phenolic compounds and flavonoids in J. maritimus and J. acutus than in J. articulatus. Qualitative and quantitative differences in antioxidant enzymes were also detected when comparing the three species and the two stress treatments. Accordingly, glutathione reductase and superoxide dismutase activities increased in the two halophytes under both stresses, but only in response to drought in J. articulatus. In contrast, ascorbate peroxidase activity varied between and within species according to treatment. These results show the relative importance of different antioxidant responses for stress tolerance in species with distinct ecological requirements. The salt-sensitive J. articulatus, contrary to the tolerant taxa, did not activate enzymatic antioxidant responses to salinity-induced oxidative stress.

Floristic and Inventory Study of Mallaha Wetland Tripoli – Libya

The aim of this study is to investigate the biodiversity status of Al-Hadaba Treatment Plant, the study was carried out in the period between February and June 2016, with one trip per week, the result of the survey let to collection and identification of 90 plant species belonging to 24 families and 65 genera, of which 24 species are belonging to monocotyledons and 66 belonging to dicotyledons. Floristic analysis were carried out which showed the perdominance of the family Poaceae with 18 species followed by the family AsteraceaE with 16 species, the result was also showed the predominance of the genus juncus with 4 species. Life form analysis a showed perdominance of Therophytes with 62 species. Kerwords: Flora – Biodiversity – Halophytes – Sabkha – Salt marsh.

Phenanthrenes from aerial part of Juncus setchuensis with anxiolyticactivity

Ten phenanthrenes, two organic acids, one organic acid ester and one flavonoid were isolated from the aerial part of Juncus setchuensis by various chromatographic techniques usingsilica gel, polyamide, Sephadex LH-20 as solid phases, and preparative HPLC. Their structures were identified by MS and NMR spectroscopic data as effusol(1), juncusol(2), juncuenin D(3), dehydroeffusol(4), dehydrojuncusol(5), juncuenin B(6),dehydrojuncuenin B(7), 2-methoxyl-7-hydroxyl-1-methyl-5-vinyl phenanthrene(8), 2-hydroxyl-7-carboxy-1-methyl-5-vinyl-9,10-dihydrophenanthrene(9), 2-hydroxyl-7-carboxyl-1-methyl-5-vinylphenanthrene(10), luteolin(11), vanillic acid(12), daphnetin(13), p-coumaric acid(14), respectively. Compound 13 was isolated from the genus Juncus for the first time and compounds 5, 8-12 were isolated from J. setchuensis for the first time. The elevated plus-maze(EPM) was used to evaluate the anxiolytic activity of compounds 6 and 7. Compound 6 at 5 mg•kg⁻¹ and 10 mg•kg⁻¹ showed anxiolytic activity as well as compound 7 at 10 mg•kg⁻¹ and 20 mg•kg⁻¹.

Evaluation of impacts of management in an anthropogenic peatland using field and remote sensing data

Peatlands are a type of wetland characterized by the accumulation of organic matter, called peat, and are important carbon reservoirs. In areas with poor drainage, human‐induced forest fires and logging can produce flooded conditions and organic matter accumulation, which generates an ecosystem called anthropogenic peatland. Productive management activities such as Sphagnum moss harvesting and livestock grazing take place there. Our hypothesis was that productive management has a strong impact on the aboveground C reservoir and increases the presence of exotic species. We established 44 sampling points in a 16‐ha anthropogenic peatland on Chiloé Island, Chile, comparing productive and conservation types of managements. Carbon stocks, vegetation structure and composition variables were quantified. These variables were used to classify the ecosystem into microsites to analyze the different locations in the peatland. In addition, predictive models of aboveground carbon were created using Landsat 8 OLI and Pleiades images. The results revealed a carbon stock of 11.99 ± 0.77 kg C m−2, which is smaller than in natural peatlands, and showed a wide variability of conditions within the peatland itself. This variability, mainly expressed in aboveground carbon, produces microsites dominated by either shrubs, species of the genus Juncus or grasses. Productive management reduced accumulated carbon in the aboveground stock and in the woody debris. However, the strongest impact was found on the vegetation variables, with a decrease in total cover, cover of shrubs and herbaceous plants, and in vegetation height. There was also an increase in the richness and presence of exotic species. The spatial prediction of aboveground carbon yielded significant results using only spectral indices, showing also that the impact of productive management is not homogenous, being less intense in waterlogged areas. This study is the first to quantify carbon reservoirs in this type of ecosystem and to propose variables that can be used as indicators of the impact of human activities.

First report of the occurrence of Livia junci (Schrank, 1789) (Hemiptera: Psyllidae) on Juncus fontanesii J. Gay ex Laharpe (Juncaceae) from Portugal

“Witches’ brooms” is a disease or deformity in a plant where the natural structure of the plant is changed, i.e., a dense mass of shoots grows, usually from a single point, with the resulting structure resembling a broom. The specimens of Juncus fontanesii J. Gay ex Laharpe were collected on July 21, 2003, in Portugal (LISU 189105). We observed the larvae of the last (i.e., fifth) stadium of Livia junci (Schrank, 1789) (Hemiptera: Psyllidae). Many exuvia of the early larval stages from Livia junci were obtained from the galls. This confirmed that the parasites lived in its larval period on Juncus fontanesii. Additionally, J. fontanesii formed the galls as a result of response to feeding, similar to other representatives of the genus Juncus. Livia junci is the only representative of the genus Livia that feeds on Juncus species in the Western Palearctic area.

Seed coat morphology of the genus Juncus L. (Juncaceae) and its systematic significance in Northeast of Iran

The seed morphology of six species of the genus Juncus L. (Juncaceae), involving wild annuals and perennials was studied in Northeast of Iran using Light and Scanning Electron Microscope (SEM). Seed morphology (light microscope) of the investigated species exhibits certain variations in shape, size and surface ornamentation. Results of SEM analysis reveals that there are different patterns of seed surface. Seed shape and surface structure exhibit some diversity among taxa indicating systematic significance in species differentiation. An identification key to the investigated taxa is provided based on seed characters in this research.

DNA variation within Juncaceae: comparison of impact of organelle regions on phylogeny

A phylogenetic analysis of the Juncaceae was conducted to assess relationships among the genera Juncus, Luzula and five other small South American genera (Distichia, Marsippospermum, Oxychloe, Patosia and Rostkovia). We examined parallel datasets from organelles (mtDNA: atp1 gene, cpDNA: trnL intron, trnL-F intergenic spacer, rbcL gene) with respect to qualities relevant to the phylogenetic analysis of the Juncaceae. The main aim of our work was to produce a robust phylogeny of the Juncaceae validated by data from both organelles. Our data confirm the monophyly of the genus Luzula, but do not provide support for monophyly of the genus Juncus. The majority of taxa clustered within two subgenera, Agathryon and Juncus, morphologically supported by the presence or absence of bracteoles and cymose or racemose inflorescences, respectively. The subgenus Juncus is divided into two separate clades, the first closely related to the subgenus Agathryon and the second in the most basal part of the tree. Moreover, small South American genera clustered together with Juncus sect. Graminifolii and also with Juncus sect. Juncus. In fact, comparison of results from separate analyses of mitochondrial and plastome genes demonstrates that the general resolution of main topology of the atp1 tree is similar to the separate rbcL tree; the genus Juncus is better resolved, but the genus Luzula remains mainly polytomic.

The Juncaceae-Cyperaceae Interface: A Combined Plastid Sequence Analysis

Phylogenetic relationships of Juncaceae and related families of Cyperales were investigated using DNA sequence data from the plastid rps16 intron, trnL intron, and trnL-F intergenic spacer. Results using parsimony analysis of the aligned matrices find Juncaceae and Cyperaceae to be monophyletic families, which form a clade sister to a monophyletic Thurniaceae that includes Prionium (Prioniaceae), all three clades with 100% bootstrap support. Within Juncaceae, the genus Lazula is monophyletic with 100% bootstrap support and sister to the rest of Juncaceae. Further groupings within the family indicate that the genus Juncus may be monophyletic only with the inclusion of the single-flowered genera of Juncaceae (Distichia, Oxychloe, Marsippospermum, and Rostkovia; sequences of Patosia were not included). Major groupings within Juncus are supported by the morphological characters of septate or non-septate leaves and the presence or absence of bracts subtending the flowers, which have been used to define subgenera and sections within Juncus.

RESPONSES OF HALOPHYTES TO SALT STRESS

Halophytes. plants naturally adapted to conditions of high salinity in the soil. have been the subject of many different studies but. paradoxically. not so much to investigate the mechanisms of salt tolerance at the biochemical and molecular level. Halophytes can be considered important. but underutilised. genetic resources for the identification of salt tolerance determinants. We present here a brief summary of the initial results of our ongoing. multidisciplinary studies on the general responses to salt stress in halophytes of the genera Plantago and Juncus. focusing on the effect of NaCl on seed germination. vegetative growth. reproductive development. and on the accumulation of mono and divalent cations and putative osmolytes in the aerial part of the plants

Responses of halophytes to salt stress.

Halophytes, plants naturally adapted to conditions of high salinity in the soil, have been the subject of many different studies but, paradoxically, not so much to investigate the mechanisms of salt tolerance at the biochemical and molecular level. Halophytes can be considered important, but underutilised, genetic resources for the identification of salt tolerance determinants. We present here a brief summary of the initial results of our ongoing, multidisciplinary studies on the general responses to salt stress in halophytes of the genera Plantago and Juncus, focusing on the effect of NaCl on seed germination, vegetative growth, reproductive development, and on the accumulation of mono and divalent cations and putative osmolytes in the aerial part of the plants.

Phylogenetic relationships within Luzula DC. and Juncus L. (Juncaceae): A comparison of phylogenetic signals of trnL-trnF intergenic spacer, trnL intron and rbcL plastome sequence data.

Juncus and Luzula are the largest, almost cosmopolitan, genera in the Juncaceae. Relationships within Juncus and Luzula and among other genera of Juncaceae (Distichia, Marsippospermum, Oxychloë, Patosia and Rostkovia) remain incompletely resolved. RbcL sequence data resolved a part of the supraspecific phylogeny, but many clades remain polytomic. For this reason, the non-coding cpDNA regions, trnL intron and trnL-trnF intergenic spacer, were sequenced. We intended to create hypotheses of relationships within Juncaceae and to test the classification of the sections, but a primary goal to this study was to assess the relationships within Juncus and Luzula and to test for monophyly of groups recognized from rbcL data (especially the monophyly of genus Luzula and the Southern Hemisphere Clade (SHC)). Furthermore, we tested the influence of different rooting and ingroup composition on the tree topology. The parsimony analyses revealed several well-supported lineages. The traditionally distinguished genus Luzula is monophyletic and Juncus is non-monophyletic. Two subgenera of Luzula (Pterodes and Luzula) are non-monophyletic, while subg. Marlenia forms a sister group to the whole Luzula clade (trnL-F data set). Within Juncus, both subgenus Juncus and subgenus Agathryon are non-monophyletic. SHC is clustered not only with the South African J. lomatophylus and J. capensis, but also together with members of the section Juncus, Caespitosi and Graminifolii. These sections form a well-separated sister group to the SHC. Within the genera Juncus and Luzula, monophyly is demonstrated for a number of groups (e.g., Juncus section Stygiopsis, Luzula section Luzula) but questioned for others (e.g., Juncus section Graminifolii). The unusual, separate positioning of Juncus trifidus and J. monanthos were clarified by trnL-trnF sequence data, but vary within the tree topology depending on outgroup selection and also due to LBA phenomenon.

Phylogenetic Relationships in the Juncaceae Inferred from Nuclear Ribosomal DNA Internal Transcribed Spacer Sequence Data

The Juncaceae includes seven genera and ca. 440 species and is cosmopolitan in distribution. The bulk of the species diversity is found in Juncus (315 species) and Luzula (115 species). Here I present a phylogenetic study within Juncaceae that focuses on the large genus Juncus, using maximum parsimony, maximum likelihood, and Bayesian inference phylogenetic analyses of the nuclear ribosomal DNA internal transcribed spacer region (ITS), and samples the genera Distichia, Juncus, Luzula, and Oxychloe. The ITS data support the placement of Oxychloe with the other cushion plant genus Distichia well within the family, contrary to the placement as sister to the Cyperaceae in previous studies. Juncus is paraphyletic, with all of the other sampled Juncaceae genera nested within it. Luzula appears related to Juncus capitatus and Juncus trifidus, while the two cushion plant genera, Distichia and Oxychloe, are sister taxa and are nested within a clade of Juncus species from Juncus subgenus Juncus sections Juncotypus ...

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Notes relating to the Flora of Bhutan: XXIV. Juncaceae

The following new taxa, combinations and synonymy in the genus Juncus from E Himalaya and SW China are proposed: J. bryophilus Noltie sp. nov.; J. spumosus Noltie sp. nov.; J. glaucoturgidus Noltie sp. nov.; J. hydrophilus Noltie sp. nov.; J. longiflorus (A. Camus) Noltie comb. & stat. nov.; J. duthiei (C.B. Clarke) Noltie comb. nov. of which the following are synonyms: J. rohtangensis Aswal & Goel, J. sikkimensis Hook.f. var. monocephalus Hook.f. and J. harae Miyam. & H. Ohba; J. bhutanensis Satake is reduced to synonymy of J leucomelas Royle ex D. Don, J. pseudocastaneus (Lingelsh.) Sam. to that of J. sikkimensis; J. tratangensis Satake to that of J. ochraceus Buchenau, J. unifolius A.M. Lu & Z.Y. Zhang to that of J. minimus Buchenau; J. phaeocarpus A.M. Lu & Z.Y. Zhang to that of J. grisebachii Buchenau; J. longibracteatus A.M. Lu & Z.Y. Zhang to that of J. kingii Rendle; J. luteocarpus Satake, the illegitimate J. albescens Satake and J. yoskisukei Goel to that of J. concinnus D. Don and J. bracteatus Buchenau to that of, J. benghalensis Kunth.J. perpusillus Sam. is reported new to Sikkim and Nepal; J. amplifolius A. Camus new to Bhutan, Sikkim and Nepal; J. trichophyllus W.W. Sm. new to Nepal and Bhutan; J. nepalicus Miyam. & H. Ohba new to Sikkim. J. uniflorus W.W. Sm. is lectotypified. Notes on J. spectabilis Rendle and J. biglumoides Hara are given.

Fossil seed cuticles from the Upper Cretaceous Whitemud beds of Alberta and Saskatchewan, Canada

Abundant fossil cuticles are associated with megaspores in the Upper Cretaceous Whitemud beds of the southern Alberta plains and in the Whitemud Formation of the Cypress Hills. Form genera Spermatites Miner and Costatheca (Dijkstra) Hall are emended, and the new genus Carpotheca is described. The three genera are differentiated by shape and orientation of cuticular cells. Ten new species of seed cuticles are described. The affinity of Spermatites with the extant genus Juncus L. is reaffirmed, and it is suggested that Costatheca may be related to extant species of Butomus L. In the Whitemud, Costatheca is more abundant in the Alberta plains, whereas Spermatites and Carpotheca are better represented in the Cypress Hills. The fossil microfloral assemblage indicates that these beds were deposited in a continental, fluviatile to lacustrine environment, having a subtropical climate, in agreement with previous sedimentological, isotopic, and palynological investigations.