Query: Poaceae

title: Chemical composition and cardiovascular effects induced by the essential oil of Cymbopogon citratus DC. Stapf, Poaceae, in rats
abstract: Cymbopogon citratus DC. Stapf, Poaceae, is used in the folk medicine for hypertension treatment. This work investigated the chemical composition and cardiovascular effects in rats of C. citratus essential oil (EOCC) A phytochemical screening demonstrated the presence of eight constituents, being geranial the major compound (43.08% In rats, EOCC (1, 5, 10, and 20 mg/kg, i.v. induced transient hypotension and bradycardia that were attenuated by atropine and sodium thiopental, but not by L NAME or indomethacin. In rings of rat superior mesenteric artery pre contracted with phenylephrine, EOCC (1 to 3000 ug/mL) induced relaxation that was not affected after removal of the endothelium, after TEA or in rings pre contracted with KCl (80 mM) Furthermore, EOCC (1000 ug/mL) was not able to induce additional effect on maximal relaxation of nifedipine (10 uM) In conclusions, EOCC induces hypotension, possibly by reduction in vascular resistance caused by inhibition of the Ca2+ influx, and bradycardia probably due to an activation of cardiac muscarinic receptors.

title: Inference of phylogenetic relationships among the subfamilies of grasses (Poaceae: Poales) using meso scale exemplar based sampling of the plastid genome.
abstract: To clarify phylogenetic relationships among grass (Poaceae) subfamilies and to better resolve the placement of Poaceae in Poales, we surveyed 17 plastid genes and associated noncoding regions ~15.5 kb per taxon, about 1/10 of the plastid genome) for exemplar representatives from 10 grass subfamilies and a broad sample of related monocots. We found general concordance in relationships and support levels among gene regions and data partitions across analyses, with some exceptions in Bayesian analyses. Different phylogenetic criteria generally agreed on backbone relationships, and the support values we inferred were generally as good as or better than those in other studies that employed more taxa for fewer genes to estimate the same backbone. Within grasses, we found robust support for the monophyly of subfamily Anomochlooideae and for the Bambusoideae Ehrhartoideae Pooideae (BEP) clade, and moderate support for a sister group relationship between Bambusoideae and Pooideae. Most relationships in the strong.

title: Poaceae phytoliths from the Niassa Rift, Mozambique
abstract: The most common grass phytoliths from "Zambezian" miombos are described here for the first time. Their potential for long term preservation in sediments makes them a useful tool in the reconstruction of ancient plant communities and plant/human interactions. We processed 60 plant samples (26 identified genera and species) with an average of 300 phytoliths counted per sample to a total of 18,586. Forty seven morphotypes were described as per the International Code for Phytolith Nomenclature, with exceptions, including forty five discreet shapes and two articulated forms, which can be used as comparative reference materials. We conducted three forms of statistical analyses: Discriminant Analysis, Cluster Analysis, and Principal Component Analysis. The highest biomineral content was recorded among the Bambuseae and Paniceae, while the lowest silica production is detected in the Cynodonteae tribe. Typologically, the subfamily Panicoideae yielded 50% of the types reported here, 32% are from the Chloridoideae, 12% from the Bambusoideae, and 8% from the Arundinoideae sensu lato. Overall, the idealized Zambezian Poaceae phytolith spectrum is dominated by a small subset of Poaceae short cells, which include five morphotypes conventionally associated with Panicoid grasses (Bilobate concave outer margin long shaft, Bilobate concave outer margin short shaft, Bilobate convex outer margin long shaft, Bilobate convex outer margin short shaft, Cross) one morphotype commonly seen in Chloridoid taxa (saddle) and two types that appear across subfamily boundaries (tower, tower horned) The next logical step to take in regional phytolith research is the account of phytoliths deposited in soils underneath living plants, for they represent the interface between existing vegetation communities and the inevitably distorted fossil assemblages that the paleobotanist uses for environmental reconstruction.

title: Population demography influences climatic niche evolution: evidence from diploid American Hordeum species (Poaceae)
abstract: In this study, we explore the interplay of population demography with the evolution of ecological niches during or after speciation in Hordeum. While large populations maintain a high level of standing genetic diversity, gene flow and recombination buffers against fast alterations in ecological adaptation. Small populations harbour lower allele diversity but can more easily shift to new niches if they initially survive under changed conditions. Thus, large populations should be more conservative regarding niche changes in comparison to small populations. We used environmental niche modelling together with phylogenetic, phylogeographic and population genetic analyses to infer the correlation of population demography with changes in ecological niche dimensions in 12 diploid Hordeum species from the New World, forming four monophyletic groups. Our analyses found both shifts and conservatism in distinct niche dimensions within and among clades. Speciation due to vicariance resulted in three species with no pronounced climate niche differences, while species originating due to long distance dispersals or otherwise encountering genetic bottlenecks mostly revealed climate niche shifts. Niche convergence among clades indicates a niche filling pattern during the last 2 million years in South American Hordeum. We provide evidence that species, which did not encounter population reductions mainly showed ecoclimatic niche conservatism, while major niche shifts occurred in species which have undergone population bottlenecks. Our data allow the conclusion that population demography influences adaptation and niche shifts or conservatism in South American Hordeum species.

title: The complete chloroplast genome of tall fescue (Lolium arundinaceum; Poaceae) and comparison of whole plastomes from the family Poaceae.
abstract: In this paper, we describe the complete chloroplast genome of Lolium arundinaceum. This sequence is the culmination of a long term project completed by >400 undergraduates who took general genetics at Middle Tennessee State University from 2004 2007. It was undertaken in an attempt to introduce these students to an open ended experiential/exploratory lesson to produce and analyze novel data. The data they produced should provide the necessary information for both phylogenetic comparisons and plastome engineering of tall fescue. The fescue plastome (GenBank FJ466687) is 136048 bp with a typical quadripartite structure and a gene order similar to other grasses; 56% of the plastome is coding region comprised of 75 protein coding genes, 29 tRNAs, four rRNAs, and one hypothetical coding region (ycf) Comparisons of Poaceae plastomes reveal size differences between the PACC (subfamilies Panicoideae, Arundinoideae, Centothecoideae, and Chloridoideae) and BOP (subfamilies Bambusoideae, Oryzoideae, and Pooideae) clades. Alignment analysis suggests that several potentially conserved large deletions in previously identified intergenic length polymorphic regions are responsible for the majority of the size discrepancy. Phylogenetic analysis using whole plastome data suggests that fescue closely aligns with Lolium perenne. Some unique features as well as phylogenetic branch length calculations, however, suggest that a number of changes have occurred since these species diverged.

title: A Revision of Deschampsia, Avenella, and Vahlodea (Poaceae, Poeae, Airinae) in South America1
abstract: A revision of the species of Deschampsia P. Beauv. Avenella (Bluff Fingerh. Drejer, and Vahlodea Fr. (Poaceae, Poeae, Airinae) present in South America is given. Fifteen species of Deschampsia and two monospecific genera segregated from Deschampsia Avenella and Vahlodea are found in the Andes of Argentina and Chile south of 30degS, typically in humid or damp sites and wetlands. Isolated populations of the cosmopolitan D. cespitosa (L. P. Beauv. are also found in Bolivia and highlands of southern Brazil. Keys to differentiate among the species of Deschampsia and the allied genera Avenella and Vahlodea are provided. A lectotype is designated for D. berteroana (Kunth) Trin.

title: Evidence of natural hybridization in Brachiaria humidicola (Rendle) Schweick. (Poaceae: Panicoideae: Paniceae)
abstract: Polyploidy and aneuploidy are conspicuous features of chromosomal evolution in the Poaceae; at least 80% of grass species are of polyploid origin (Stebbins 1985) The original basic chromosome number for the Poaceae is not known and has been the subject of much speculation. In the large tribe Paniceae, which includes the genus Brachiaria, the most common basic chromosome number is x 9 (De Wet 1986) The predominance of x 9 in Brachiaria genus had been reported in several studies (Basappa et al. 1987; Honfi et al. 1990; Bernini and Marin Morales 2001; Mendes Bonato et al. 2002, 2006; Utsunomiya et al. 2005) More recently, a new chromosome number, x 6, was determined for B. dictyoneura (Risso Pascotto et al. 2006) There is a large predominance of polyploid forms in the genus Brachiaria and tetraploids prevail. The origin of polyploidy, however, has never been pursued in this genus. Cytological evidence from analysis of meiotic behaviour, including chromosome pairing at diakinesis, led to the suggestion that autotetraploidy and segmental allopolyploidy could have contributed to evolution in some species (Mendes Bonato et al. 2002, 2006; Utsunomiya et al. 2005) On the other hand, in two pentaploid accessions of B. brizantha (2n 5x 45) there was clear evidence of allopolyploidy (Mendes et al. 2006) This paper reports the unusual cytological behaviour during meiosis in one accession of Brachiaria humidicola from the Embrapa Beef Cattle germplasm collection.

title: Allelopathic potential of Bothriochloa laguroides var. laguroides (DC. Herter (Poaceae: Andropogoneae)
abstract: Bothriochloa laguroides var. laguroides (DC. Herter, a native bluestem of America, has been shown to produce many biologically active compounds. The allelopathic potential of aqueous extracts from roots, stems and leaves was examined. Lettuce seeds (Lactuca sativa) and maize (Zea mays) the common allelopathy bioassay systems, as well as seeds from two native species, wintergreen paspalum (Paspalum guenoarum) and lovegrass (Eragrostis curvula) were germinated in the presence of aqueous extracts. Percent seed germination, root and shoot elongation were measured. After 4 and 7 days root, stem and leaf extracts caused inhibition of root and shoot elongation in all four species tested. Aqueous extracts were generally less inhibitory to seed germination. Aqueous extracts from different parts of B. laguroides var. laguroides show therefore allelopathic effects inhibiting, in particular, growth of competing plants.

title: Phylogenetics of Stipeae (Poaceae: Pooideae) based on plastid and nuclear DNA sequences
abstract: The Stipeae tribe is a group of 400 600 grass species of worldwide distribution that are currently placed in 21 genera. The 'needlegrasses' are characterized by having single flowered spikelets and stout, terminally awned lemmas. We conducted a molecular phylogenetic study of the Stipeae (including all genera except Anemanthele) using a total of 94 species (nine species were used as outgroups) based on five plastid DNA regions (trnK 5'matK, matK, trnHGUG psbA, trnL5' trnF, and ndhF) and a single nuclear DNA region (ITS) Our parsimony analysis of DNA sequences supports: the monophyly of the Stipeae including Macrochloa as sister to all other Stipeae; the removal of Lorenzochloa erectifolia from Ortachne since it does not align with Ortachne but with some species of Anatherostipa; Ptilagrostis as occurring in two separate clades; and Oryzopsis asperifolia as a monotypic genus. Achnatherum and Piptatherum as currently circumscribed are polyphyletic and we provide good support to split the former into four groups and the latter into three groups. Achnatherum s.s. Aciachne, Amelichloa, Austrostipa, Hesperostipa, Jarava s.s. Ortachne, Pappostipa, Piptatherum s.s. Piptochaetium, Ptilagrostis s.s. Stipa s.s. and Trikeraia are all well supported as monophyletic genera. Stipa capensis and S. parviflora both of African distribution are apparently misplaced and are not closely related to other species of Stipa s.s. but are allied to achnatheroids. Based on molecular evolution of plastid sequences and lemma epidermal pattern we present a stepwise model for the 1120_kap_18_32_6k.indd 511 07/06/10 21.23 512 Romaschenko et al. evolution of the Stipeae with two initial deep bifurcations followed by two further bifurcations that are geographically consistent. The segregation of new groups or clades tentatively called: Eriocoma, Nasselloid, 'Neotrinia''Piptatheropsis' and Timouria, require further study.  Classification, grasses, ITS, phylogeny, plastid DNA, taxonomy. The tribe Stipeae Dumort. consists of temperate, cool season (C3) grasses that are widespread, mostly tussock forming grasses, of predominantly open grasslands in temperate and warm temperate regions. They are characterized by having single flowered spikelets without rachilla extensions, terminallyawned lemmas where the awn is the result of fusion between the central and two lateral vascular traces, florets with three, rarely two, linear lodicules that are slightly indurate at maturity, usually with the lemma concealing the palea (if the palea is exposed when the floret is closed, then the palea is coriaceous) and small sized chromosomes with a base number x 10 12 (Tzvelev 1989) The tribe comprises approximately 400 to 600 species; the number depending on how finely the Asian taxa are divided. The Stipeae are placed in subfamily Pooideae (Grass Phylogeny Working Group (GPWG) 2001) Within Pooideae the Stipeae is an early diverging lineage that arose after the separation of the Brachyelytreae Ohwi, Lygeeae J. Presl, and Nardeae W.D.J. Koch (Davis and Soreng 2007; Soreng et al. 2007) from the remainder of tribes. There are 21 accepted genera of Stipeae (Soreng et al. 2003, 2008) Achnatherum P. Beauv. Aciachne Benth. Ampelodesmos Link, Amelichloa Arriaga and Barkworth, Anemanthele Veldkamp, Austrostipa S.W.L. Jacobs and J. Everett, Celtica F.M. Vazquez and Barkworth, Hesperostipa (M.K. Elias) Barkworth, Jarava Ruiz and Pav. Macrochloa Kunth, Nassella (Trin. Ortachne Nees ex Steud. Orthoraphium Nees, Oryzopsis Michx. Pappostipa (Speg. Romasch. P.M. Peterson and Soreng, Piptatherum P. Beauv. Piptochaetium J. Presl, Psammochloa Hitchc. Ptilagrostis Griseb. Stipa L. and Trikeraia Bor. The above 20 genera, minus Ampelodesmos (which when included in Stipeae is placed in subtribe Ampelodesminae Conert) represent 'core Stipeae' In addition, subtribe Duthieinae Pilg. ex Potztal is sometimes placed in or lumped into Aveneae Dumort. Stipeae, or Phaenospermateae Renvoize and Clayton, including in its broadest sense: Anisopogon R.Br. Danthoniastrum (Holub) Holub, Megelachne Steud. Metcalfia Conert, Podophorus Phil. Pseudodanthonia Bor and C.E. Hubb. Sinochasea Keng, Duthiea Hack. and Stephanachne Keng (Clayton and Renvoize 1986; Soreng et al. 2003, 2008; Wu and Phillips 2006) Two monotypic genera, Timouria Roshev. and Lorenzochloa Reeder and C. Reeder, are currently attributed to Achnatherum and Ortachne, respectively (Clayton and Renvoize 1986; Wu and Phillips 2006) Generic boundaries among the genera in the Stipeae are problematic, especially among those named in the 18th and 19th centuries. Delimitation among these led many 20th century agros1120_kap_18_32_6k.indd 512 07/06/10 21.23 Phylogenetics of Stipeae 513 tologists to adopt a broad concept of the genus Stipa to encompass all of the currently accepted genera except Oryzopsis, Aciachne, and Piptochaetium in the New World (Spegazzini 1901; Hitchcock 1935, 1951) and Piptatherum in the Old World (Freitag 1975, 1985) New studies were performed to describe new genera, emend generic limits, or present novel relationships (Parodi 1947, 1960; Rojas 1997; Barkworth 1983, 1990, 1993; Jacobs and Everett 1996; Penailillo 1996, 2002, 2003; 2005; Torres 1997; Barkworth and Torres 2001; Cialdella and Giussani 2002; Vazquez and Barkworth 2004; Arriaga and Barkworth 2006; Cialdella et al. 2007; Romaschenko et al. 2008) Phylogenetic inferences for Stipeae are scarce. Based on the morphological features the most comprehensive review was made by Tzvelev (1977) where phylogenetic weight was assigned to such characters as shape of the lemma and callus, and development of awn indumentum. Tzvelev (1977) reported 16 genera of Stipeae including such genera as Eriocoma Nutt. (currently attributed to Achnatherum) Parodiella Reeder and C. Reeder (Lorenzochloa which is commonly placed in Ortachne) Stephanachne (as S. nigrescens Keng) Pappagrostis Roshev. [as Stephanachne pappophorea (Hack. Keng] and Streptachne R.Br. =Aristida) Tzvelev's suggested there were two major lineages: 1) Stipa s. s. (with long lanceolate lemmas, awns having strongly developed indumentum, and sharp calluses) and; 2) Piptatherum (characterized by short lemmas, short, hairless, caducous awns and blunt calluses) The Piptatherum lineage was thought to have originated from more primitive Achnatherum like species, whereas Ptilagrostis and A. chinense (Hitchc. Tzvel. were considered to be intermediate taxa between Achnatherum and Stipa s. s. and Achnatherum and Piptatherum, respectively. Piptochaetium and Nassella were considered to be close relatives and Eriocoma was thought to be a New World vicariant of Piptatherum. Thomasson (1978, 1980, 1981, 1982, 1985) was first to document the phylogenetic importance of the lemma epidermal pattern in the Stipeae. Barkworth and Everett (1987) used this information extensively and pointed out that Stipa and Piptatherum have elongated lemma epidermal cells with sinuous lateral walls and that Achnatherum and Austrostipa have short lemma epidermal cells with slightly sinuous to strait lateral walls. Barkworth and Everett (1987) followed Tzvelev (1977) and used the shape of the lemma and callus and development of awn indumentums and therefore postulated a similar phylogenetic scheme. Hesperostipa and the 'Obtusa group' of Parodi (1946; =Anatherostipa) and Nassella and Piptochaetium, were thought to be two pairs of closely related genera. In a series of morphological studies (Barkworth 1990, 1993; Barkworth and Torres 2001; Cialdella and Guissani 2002; Thomasson 1978, 1982) and a phylogenetic study with a molecular analysis (Jacobs et al. 2000) it was suggested than Nassella and Piptochaetium shared a most recent common ancestor [i.e. to be sister genera] In more recent molecular phylogenetic analyses it was suggested that the Piptatherum/Oryzopsis complex along with Stipa s. s. and Hesperostipa were among early diverging lineages; Austrostipa was shown as a member of a derived 1120_kap_18_32_6k.indd 513 07/06/10 21.23 514 Romaschenko et al. clade (Jacobs et al. 2007) and Nassella was more closely related to Jarava than to Piptochaetium (Cialdella et. al 2007) The relationships between the Stipeae and the Phaenospermateae Duthieinae Anisopogon complex were tested in a matK (Doring et al. 2007) and ITS analysis (Romaschenko et al. 2007) In the latter analysis the poorly supported clade including Anisopogon, Danthoniastrum, Duthiea, Phaenosperma, and Sinochasea was recovered as sister clade to the Stipeae. Since the representatives of Meliceae Link ex Endl. and Diarrheneae (Ohwi) C.S. Campb. were not included in Romaschenko et al. (2007) analysis, no conclusion was suggested regarding their phylogenetic relationships. In Doring et al. (2007) a trichotomy was formed among members of the Meliceae, Stipeae, and a clade with Anisopogon, Danthoniastrum, Duthiea, Phaenosperma, and Sinochasea. The main objective of the present paper is to provide a phylogenetic hypothesis for all the currently accepted genera within the core Stipeae using plastid (trnK 5'matK, matK, trnHGUG psbA, trnL5' trnF, and ndhF) and nuclear ribosomal DNA ITS sequences. In addition, we hope to elucidate generic boundaries within the Stipeae and resolve questions regarding these lineages within the tribe.  Sampling Samples were chosen to represent the taxonomic diversity in the Stipeae. The sample set consists of 94 accessions/species  representing all accepted genera (except Anemanthele) in the Stipeae (Soreng et al. 2003) as well as major intergeneric groups within the polyphyletic genera detected in our previous study (Romaschenko et al. 2008) We sampled evenly from both American and Eurasian groups of Achnatherum and Piptatherum, and included the type species for all groups. We included South American: Aciachne, Lorenzochloa (currently included in Ortachne) and Ortachne;

title: Crossbreeding of Phyllostachys species (Poaceae) and identification of their hybrids using ISSR markers.
abstract: Crossbreeding is an efficient means to increase production and quality in plants; however, hybridization is seldom reported in bamboo. We crossbred two bamboo species Phyllostachys kwangsiensis (female parent) and Phyllostachys bambusoides (male parent) for the first time, and obtained suspected bamboo hybrids. We identified two bamboo hybrids from the above parents using PCR/ISSR. We concluded that ISSR markers are useful to identify bamboo hybrids, and that breeding between bamboo species is possible and useful.