01760nas a2200205   4500008004100000245010900041210006900150260001200219300001400231490000800245520105000253653002601303653001501329653002201344653001901366653001701385100001801402700001801420856011601438       1998                        eng d00aIsoetes microvela (Isoetaceae), a new quillwort from the coastal plain of the southeastern United States0 aIsoetes microvela Isoetaceae a new quillwort from the coastal pl  c1998///  a261 - 2750 v1003 aIsoetes microvela, sp. nov., is described from cytologically confirmed hexaploid populations from the coastal plain of North Carolina. At least one population grows over thinly-buried calcareous bedrock, a rare condition on the predominantly acidic southeastern coastal plain. It is a large quillwort of periodically inundated and scoured stream banks and shallow water. It is characterized by a densely short-crested to reticulate-tuberculate megaspore ornamentation pattern intermediate in appearance between that of I. appalachiana and I. hyemalis, an exceptionally small velum covering ± 10% of the heavily brown-streaked sporangium, and by obscurely tuberculate microspores. A key to the Isoetes of the southeastern coastal plain is presented. Isoetes microvela is suspected to represent an allopolyploid derived from the doubling of a sterile triploid hybrid, most likely I. ×bruntonii (= I. engelmannii × I. hyemalis) or I. appalachiana × I. engelmannii. Isoetes microvela is a rare species, presently known from only two populations.10aCoastal plain endemic10aIsoetaceae10aIsoetes microvela10aNorth Carolina10aPteridophyte1 aBrunton, D.F.1 aBritton, D.M.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0013638592&partnerID=40&md5=a11db8019e87e506ac5ab36185a8c4de01040nas a2200181   4500008004100000245006800041210006700109260001200176300001200188490000700200520047000207653001600677653001000693653001200703653001000715100001700725856011600742       1998                        eng d00aFungal associations in the roots of three species of Isoetes L.0 aFungal associations in the roots of three species of Isoetes L  c1998///  a33 - 370 v613 aA fungal association has been described in the roots of three species of lsoetes which flourish during the rainy season in Rajasthan (India). The mycelium is septate, branched and forms bunches of intracellular hyphae in cortical cells of young roots. The association is symbiotic and is not influenced by habitat, i.e. while the host plant is aquatic, amphibious or terrestrial. This is the first report of a fungal association with the roots of the taxon Isoetes.10aAssociation10aFungi10aIsoetes10aRoots1 aSharma, B.D.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0032078046&partnerID=40&md5=889c7296fb92f9ff06715d43eac6d16b02458nas a2200241   4500008004100000245011900041210006900160260001200229300001400241490000700255520164100262653002901903653001501932653002601947653002201973653001701995100001502012700001702027700002202044700001502066700001902081856011602100       1998                        eng d00aSulfate reduction in lake sediments inhabited by the isoetid macrophytes Littorelia uniflora and isoetes lacustris0 aSulfate reduction in lake sediments inhabited by the isoetid mac  c1998///  a307 - 3240 v603 aSulfur cycling was examined in sediments inhabited with the isoetids Littorella uniflora and Isoetes lacustris in the oligotrophic soft-water Lake Kalgaard, Denmark. Based on short-term tracer incubations sulfate reduction was measured along a transect from the shore (0.6 m) to profundal sediments (4.6 m). The sulfate reduction rates were low (0.008-0.8 mmol m-2 d-1) in the sandy shallow sediments with low organic content (&lt; 1.3 mmol C g-1 sed DW) and high redox potentials (&gt; 100 mV), whereas sulfate reduction was higher at the deeper sites (2.7-4.6 mmol m-2 d-1) with high organic content (max. 11.5 mmol C g-1 sed DW) and lower redox potentials (&lt; 100 mV). High concentrations of dissolved organic carbon (DOC) were found in the low particulate organic sediments (up to 18.4 mM), and most of the DOC pool consisted of acetate (40-77%). Reoxidation of sulfides due to root oxygen release was probably important at all sites and a positive efflux of sulfate across the sediment-water interface was measured, attaining rates (up to 4.8 mmol m-2 d-1) similar to the sulfate reduction rates. Reoxidation of sulfides was also manifested by high fraction (&gt; 80%) of reduced sulfides being accumulated as elemental sulfur or pyrite (chromium reducible sulfur, CRS). The largest pools of CRS were found in high organic sediment with vertical distributions resembling those of the sulfate reduction rates. The overall effect of isoetid growth on sulfur cycling in the rhizosphere is a suppression of sulfate reduction in low organic sediments and the governing of sulfide reoxictation in sediments with higher organic content.10aDissolved organic carbon10aFreshwater10aSubmerged macrophytes10aSulfate reduction10aSulfur pools1 aHolmer, M.1 aJensen, H.S.1 aChristensen, K.K.1 aWigand, C.1 aAndersen, F.O.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0032051759&partnerID=40&md5=cedb9f2713f49909e7234473be0de56102070nas a2200205   4500008004100000245011200041210006900153260001200222300001400234490000700248520138100255653001401636653001401650653001201664653002001676653001101696653002501707100001601732856011601748       1998                        eng d00aStudies on Annalepis from Middle Triassic along the Yangtze river and its bearing on the origin of Isoëtes0 aStudies on Annalepis from Middle Triassic along the Yangtze rive  c1998///  a768 - 7740 v403 aSpecimens of Annalepis have been found from the Middle Triassic Series in the Yangtze River valley and described, including a new species. Annalepis is similar to the living plant, Isoëtes , in many aspects, such as the herb with a corm, more or less clustering sporophylls, presence of a ligule, monolete suture microspores of Aratrisporites -type and trilete megaspores, etc. The similarities of features between the two plants indicate their close affinities and that A . brevicystis might be the ancestry of Isoëtes . Since there is a ligule on the sporophyll of Pleuromeia, the Pleuromeiaceae represented by Pleuromeia could be allied to the Isoëtaceae, and both families should belong to Isoëtales. Isoëtales represents a distinct evolutionary sequence and is inferred as being evolved probably from Palaeozoic Sigillaria . In Mesozoic age, two evolutionary lines are proposed: one as a line from Pleuromeia to Nathorstiana in relation to wood-monopolar rhizophore; the other as a line from Annalenis to Isoëtes related to herb-bipolar corm. Annalepis appeared almost simultaneously in the Yangtze River valley in early Middle Triassic, but the distribution of Annalepis was concentrated from east to west during middle-late Middle Triassic, in relation to the marine regression which occurred cyclically from east to west on the Yangtze Platform during that time.10aAnnalepis10aEvolution10aIsoetes10aMiddle Triassic10aOrigin10aYangtze river valley1 aMeng, F.-S.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0032414084&partnerID=40&md5=b6306b3189c6672809b1bab17e2dd16800756nas a2200133   4500008004100000245004500041210004500086260001200131300001400143490000700157520032500164100001700489856011600506       1998                        eng d00aFungal Associations with Isoetes Species0 aFungal Associations with Isoetes Species  c1998///  a138 - 1420 v883 aThe fungal associations present in the roots and corms of four species of Isoetes found in Rajasthan, India, are described. Fungal fruiting bodies and chlamydospores are assigned to the mycorrhizal genus Glomus, and the septate branched intracellular mycelium is assigned to the genus Rhizoctonia of the Deuteromycotina.1 aSharma, B.D.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0008039063&partnerID=40&md5=1128f92d04a506b68b8c2e708542834300903nas a2200193   4500008004100000245006200041210006200103260001200165300001400177490000700191520031300198653001200511653001200523653001600535653001400551653001100565100001700576856011600593       1998                        eng d00aAnatomy of scales and phyllopodia of Isoetes of Rajasthan0 aAnatomy of scales and phyllopodia of Isoetes of Rajasthan  c1998///  a269 - 2720 v483 aAnatomy of scales and phyllopodia of the four species of Isoetes found in Rajasthan was studied. The shapes triangular to bonnet and sizes of scales and phyllopodia vary with species; 3-12 mm × 2-9 mm in size, parenchymatous and have intermingled roots, sporangia, spores, fungal hyphae and fruiting bodies.10aAnatomy10aIsoetes10aPhyllopodia10aRajasthan10aScales1 aSharma, B.D.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-1542573923&partnerID=40&md5=d37103324e9fa9109d8eeb159846560c