摩西斗管囊霉改善连作花生根际土壤的微环境

花生(Arachis hypogaea)长期连作导致土壤环境恶化,严重影响产量和品质。丛枝菌根真菌(AMF)作为有益真菌能够与80%的陆生植物根系形成共生关系,这种共生体能够改善植物根系微环境,提高植物对营养物质的吸收和对逆境胁迫的抗性。为了探究AMF对花生连作土壤微环境的影响,该研究通过对花生连作土壤接种和未接种摩西斗管囊霉(Funneliformis mosseae)试验,在花生不同生长期检测根际土壤的酶活性、土壤矿物质含量、土壤微生物群落结构和多度的变化情况,以及对连作花生产量和品质的影响。研究结果表明:1)摩西斗管囊霉能够显著提高花生根际土壤蔗糖酶、脲酶、碱性磷酸酶和硝酸还原酶的活性; 2)摩西斗管囊霉显著增加花生连作土壤中全氮、全磷、全钾、速效磷和速效钾的含量; 3)摩西斗管囊霉显著降低土壤中有害真菌曲霉菌属(Aspergillus)的多度,减少镰刀菌属(Fusarium)和赤霉菌属(Gibberella)的多度,但是没有达到显著水平,显著增加有益细菌放线菌Gaiella属的多度; 4)摩西斗管囊霉显著提高连作花生的产量,增加籽仁中蛋白质、油酸和亚油酸的含量。因此,摩西斗管囊霉能够改善连作花生根际土壤微生态环境,增强连作土壤对致病菌的抵抗能力,从而缓解连作障碍对花生根系的危害。     

摩西斗管囊霉改善连作花生根际土壤的微环境

花生(Arachis hypogaea)长期连作导致土壤环境恶化, 严重影响产量和品质。丛枝菌根真菌(AMF)作为有益真菌能够与80%的陆生植物根系形成共生关系, 这种共生体能够改善植物根系微环境, 提高植物对营养物质的吸收和对逆境胁迫的抗性。为了探究AMF对花生连作土壤微环境的影响, 该研究通过对花生连作土壤接种和未接种摩西斗管囊霉(Funneliformis mosseae)试验, 在花生不同生长期检测根际土壤的酶活性、土壤矿物质含量、土壤微生物群落结构和多度的变化情况, 以及对连作花生产量和品质的影响。研究结果表明: 1)摩西斗管囊霉能够显著提高花生根际土壤蔗糖酶、脲酶、碱性磷酸酶和硝酸还原酶的活性; 2)摩西斗管囊霉显著增加花生连作土壤中全氮、全磷、全钾、速效磷和速效钾的含量; 3)摩西斗管囊霉显著降低土壤中有害真菌曲霉菌属(Aspergillus)的多度, 减少镰刀菌属(Fusarium)和赤霉菌属(Gibberella)的多度, 但是没有达到显著水平, 显著增加有益细菌放线菌Gaiella属的多度; 4)摩西斗管囊霉显著提高连作花生的产量, 增加籽仁中蛋白质、油酸和亚油酸的含量。因此, 摩西斗管囊霉能够改善连作花生根际土壤微生态环境, 增强连作土壤对致病菌的抵抗能力, 从而缓解连作障碍对花生根系的危害。     

AMF和植物富集土壤中铅和镉的效应

为了筛选更适合修复土壤重金属污染的丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)和寄主植物组合,对二月兰(Orychophragum violaeeus)、龙葵(Solanum nigrum)和麦冬(Ophiopogon japonicus)接种AM真菌摩西管柄囊霉(Funneliformis mosseae)和根内球囊霉(Glomus intraradices),通过测定Pb(1 000 mg/kg)和Cd(1.5 mg/kg)污染土壤中上述3种植物生长状况及其对Pb和Cd吸收与富集能力的影响,旨在获得富集重金属能力较强的AM真菌+植物组合。结果表明,施加Cd土壤中二月兰和麦冬的生物量高于对照,施加Pb或Cd处理显著降低龙葵的生长。龙葵对Pb和Cd富集能力最强,麦冬最弱;二月兰对Pb和Cd的转移能力最强。供试植物对Cd的富集能力和转移能力均大于对Pb的富集能力和转移能力。在Pb和Cd的胁迫下,摩西管柄囊霉和根内球囊霉均能促进供试植物的生长发育,并增加植株对Pb和Cd的富集系数,其中,摩西管柄囊霉对龙葵生物量、Pb和Cd富集系数的效应最大。综合考虑植物本身的生物量、对Pb和Cd的耐受力和富集能力,结论认为摩西管柄囊霉+龙葵组合是修复Pb或Cd污染土壤的高效AM真菌+植物组合之一,相关机制有待进一步研究。     

AM真菌对百合调节激素平衡与细胞渗透性以及改善耐盐性的研究

该试验以东方百合(Lilium brownii)品种‘西伯利亚’和丛枝菌根(AM)真菌摩西斗管囊霉(Funneliformis mosseae)、变形球囊霉(Glomus versiforme)为材料,在温室盆栽条件下,设置NaCl胁迫(0、0.4%、0.8%和1.2%NaCl溶液处理)和接种AM真菌[接种摩西斗管囊霉、变形球囊霉、摩西斗管囊霉+变形球囊霉及未接种对照]双因素试验,分析各处理百合的激素平衡与细胞渗透性变化特征,以明确AM真菌提高百合耐盐性的效应,初步探索AM真菌增强百合耐盐性的作用机制。结果表明:(1)接种AM真菌能有效增加盐胁迫下百合植株的株高和生物量,显著提高百合耐盐系数,双接种处理的株高及地上、地下部分干重在1.2%NaCl胁迫下分别比未接种对照显著增加8.9%、14.5%和11.2%。(2)接种AM真菌能显著提高盐胁迫下百合植株叶片的矿质元素P、K、S含量,显著降低叶片内Na和Fe含量,双接种处理的P、K、S含量在1.2%NaCl胁迫下分别比对照提高10.9%、8.3%、13.7%,而其Na和Fe含量分别显著下降28.4%和66.4%。(3)接种AM真菌能显著提高盐胁迫下百合内源激素吲哚乙酸(IAA)和脱落酸(ABA)含量,双接种处理在1.2%NaCl胁迫下百合内源IAA、ABA含量分别是对照的1.2和1.5倍。(4)接种AM真菌能显著提高盐胁迫下百合可溶性蛋白含量,显著降低其脯氨酸含量,双接种处理在1.2%NaCl胁迫下比对照的升降幅度分别为69%和31%。(5)接种AM真菌能显著降低盐胁迫下百合叶片丙二醛和相对电导率,双接种处理在1.2%NaCl胁迫下比对照分别显著下降58.1%和9.0%。研究发现,AM真菌可以通过增强百合对养分的吸收、降低氧化胁迫造成的伤害、调节植物内源激素平衡状况与细胞渗透性来增强自身的耐盐能力,且双接种处理的效果优于单一接种。     

丛枝菌根真菌对砷胁迫下棉花根系形态和生理特征的影响

以棉花品种‘大铃棉69号’为材料,通过室内盆栽试验,将两种丛枝菌根真菌根——内根孢囊霉(Rhizophagus intraradices,RI)和摩西斗管囊霉(Funneliformis mosseae,FM)分别接种棉花根部,分析不同土壤砷浓度(0、100、200 mg/kg)条件下丛枝菌根真菌对棉花生长、根系特征、细胞膜透性、抗氧化酶活性以及砷在棉花体内积累和转移的影响,为丛枝菌根真菌在土壤砷污染修复中的合理应用提供理论支撑。结果表明:(1)随着砷胁迫的加重,棉花生长、根系发育、根系活力、抗氧化酶系统(SOD、POD、CAT)和渗透调节系统(可溶性糖、可溶性蛋白、脯氨酸)均受到明显抑制。(2)接种RI和FM显著提高了棉花的株高、生物量、根冠比,根系活力;降低了棉花地上和地下部的砷含量和砷转移系数;提高了棉花总根长、根表面积、根体积、根尖数、根叉数等根系形态指标,并降低其0～0.2 mm径级的根长百分比,增加其0.5～1.0 mm和1.0 mm径级的根长百分比;促使棉花叶和根中可溶性糖、可溶性蛋白、脯氨酸等渗透调节物质含量和SOD、POD、CAT等抗氧化酶活性不同程度升高,并使相对电导率、MDA含量降低;其中,摩西斗管囊霉接种效果优于根内根孢囊霉。研究发现,在土壤砷胁迫条件下,接种丛枝菌根真菌可促进棉花生长和根系发育,降低棉花体内砷浓度并抑制其向地上转移,同时激活抗氧化系统和渗透调节系统来减轻砷对棉花的毒害作用,增强棉花对土壤砷胁迫的耐受能力,且摩西斗管囊霉接种效果更佳。     

丛枝菌根真菌与高羊茅协同修复镉污染土壤

本研究采用温室盆栽试验,利用丛枝菌根（AM）真菌摩西管柄囊霉Funneliformis mosseae进行接种试验,研究了在Cd胁迫下（0、5、15和30mg/kg）接种AM真菌对高羊茅Festuca elata ‘Crossfire II’的生物量、防御酶活性、磷和镉（Cd）含量的影响。结果表明,随着Cd浓度的增加,高羊茅的菌根侵染率和菌根相对依赖性有所增加。接种AM真菌改善了磷从植株根系向地上部的转运,有助于植株在地上部积累更多的磷。此外,AM真菌和Cd胁迫对高羊茅植株抗氧化酶活性都有显著影响,在镉胁迫下,与未接种植株相比,接种AM真菌显著提高了植株的过氧化氢酶活性,而显著降低了植株的丙二醛含量。与未接种植株相比,接种摩西管柄囊霉显著提高了寄主植物对Cd的富集能力,有利于重金属在根部的积累,同时降低了地上部的Cd含量。本研究表明,高羊茅-丛枝菌根共生体在Cd污染土壤的修复中具有潜在应用价值。     

两种AM真菌对冬小麦根系锌吸收的影响

无论在温室还是在大田条件下,菌根(AM)真菌均能够侵染冬小麦,但其对冬小麦锌(Zn)吸收的效应及机制尚不明确。本研究将摩西管柄囊霉Funneliformis mosseae和根内根孢囊霉Rhizophagus intraradices分别接种于冬小麦Triticum aestivum(品种:小偃22)根围,10周后分别利用菌根化幼苗进行短期(0–90min)Zn吸收动力学试验和长期(0–210min)Zn吸收积累试验,并研究AM真菌侵染对冬小麦根系形态特征的影响。结果表明,AM真菌通过增加根系长度和根尖数量来扩大冬小麦根系Zn吸收的有效面积、Zn最大吸收速度V_(max)和Zn~(2+)流入根系的速度α,进而促进冬小麦根系对Zn的吸收。接种摩西管柄囊霉降低了K_m值而接种根内根孢囊霉增加了K_m值,这可能与不同AM真菌对冬小麦根系形态影响及对Zn转运蛋白基因表达的影响存在差异有关。     

丛枝菌根真菌促进湿地植物对污染水体中镉的吸收

丛枝菌根真菌(AMF)具有促进植物生长、增强植物耐重金属毒害及修复重金属污染生境的作用.本试验于模拟湿地系统中设0、5、10和20 mg·L^-1镉浓度,对芦苇和狼尾草分别进行接种和不接种摩西斗管囊霉(Fm)、根内根孢囊霉(Ri)处理.结果表明: 镉污染降低了AMF侵染;接种AMF提高了芦苇和狼尾草的株高、干质量、叶绿素含量、地上部与根内的氮和镉含量,增强了根系对镉的富集能力,降低了镉转移系数.在5 mg·L^-1镉处理下,接种Fm的芦苇处理的各项指标均高于其他处理,其AMF侵染率为60.6%,每毫米根长的侵入点和泡囊数分别为2.3和3.7;与不接种对照相比,接种Fm的芦苇地上部与根系干质量分别提高69.1%和75.0%,地上部与根系氮含量分别提高38.7%和27.8%,叶绿素含量和株高分别增加3.8%和11.1%.湿地系统镉浓度与植株地上部和根内的镉含量呈显著正相关.在20 mg·L^-1镉处理下,接种Fm的芦苇地上部和根内镉含量达到最大值182.4和663.3 mg·kg^-1,镉转移系数最低,为0.27,而富集系数最高,为0.55.Fm+芦苇是本试验条件下吸收富集污染水体中镉的最佳组合.     

高粱和地球囊霉联合修复锶污染土壤研究

本研究选用高粱(Sorghum bicolor(L.) Moench)为修复植物用于治理土壤锶污染,接种地球囊霉(Glomus geosporum),比较不同锶浓度(0、75、725、975 mg/kg)处理下,地球囊霉对高粱修复锶污染土壤的调控作用。结果表明:在所有锶处理下,接种地球囊霉的侵染率都高于50%。与无菌根处理相比,在75、725 mg/kg锶处理,接种地球囊霉的高粱的生物量、株高和根长都显著增加(P0.05)。接种地球囊霉的高粱表现出显著的菌根依赖性(P0.05)。其中最显著的是75 mg/kg处理,菌根依赖性为136.92%,并且在0—975 mg/kg锶处理中菌根依赖性都大于100%。地球囊霉侵染的高粱,叶片和根中的锶含量与无菌根处理组相比显著增加(P0.05),接种菌根组的转运系数都高于与无菌根组。接种地球囊霉,土壤中的全磷含量和速效磷含量显著降低(P0.05)。全磷减少了6.52%—18.77%,速效磷减少了12.38%—27.43%。接种AMF显著增加了土壤磷酸酶活性(P0.05),与无菌根组相比,增加了19.67%—32.56%。综上所述,地球囊霉能够促进高粱对锶的富集能力和耐受性,在锶污染(75—725 mg/kg)时接种地球囊霉的效果最好。     

磷水平与丛枝菌根真菌对桔梗生长及品质的影响

明确不同磷水平条件下接种丛枝菌根真菌(AMF)对桔梗质量与产量的影响.采用盆栽法,设计P0(20 mg/kg)、P1(50 mg/kg)、P2(80 mg/kg)、P3(140 mg/kg)共4个磷水平,同一磷水平分别接种摩西斗管囊霉(Funneliformis mosseae,FM)、根内根孢囊霉(Rhizophag...     

Foreign exploration for Scirtothrips perseae Nakahara (Thysanoptera: Thripidae) and associated natural enemies on avocado (Persea americana Miller)

Scirtothrips perseae Nakahara was discovered attacking avocados in California, USA, in 1996. Host plant surveys in California indicated that S. perseae has a highly restricted host range with larvae being found only on avocados, while adults were collected from 11 different plant species. As part of a management program for this pest, a “classical” biological control program was initiated and foreign exploration was conducted to delineate the home range of S. perseae, to survey for associated natural enemies and inventory other species of phytophagous thrips on avocados grown in Mexico, Guatemala, Costa Rica, the Dominican Republic, Trinidad, and Brazil. Foreign exploration efforts indicate that S. perseae occurs on avocados grown at high altitudes (>1500 m) from Uruapan in Mexico south to areas around Guatemala City in Guatemala. In Costa Rica, S. perseae is replaced by an undescribed congener as the dominant phytophagous thrips on avocados grown at high altitudes (>1300 m). No species of Scirtothrips were found on avocados in the Dominican Republic, Trinidad, or Brazil. In total, 2136 phytophagous thrips were collected and identified, representing over 47 identified species from at least 19 genera. The significance of these species records is discussed. Of collected material 4% were potential thrips biological control agents. Natural enemies were dominated by six genera of predatory thrips (Aeolothrips, Aleurodothrips, Franklinothrips, Leptothrips, Scolothrips, and Karnyothrips). One genus each of parasitoid (Ceranisus) and predatory mite (Balaustium) were found. Based on the results of our sampling techniques, prospects for the importation of thrips natural enemies for use in a “classical” biological control program in California against S. perseae are not promising.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

New species and new combinations in Peruvian Orchidaceae

seventeen new species and combinations are proposed in the generaChondrorhyncha, Cischweinfia, Cochlioda, Eloyella, Encyclia, Kefersteinia, Koellensteinia, Macroclinium, Rodriguezia, Solenidiopsis, andStenia. All new species are illustrated. A key is provided for 2-flowered species ofMacroclinium, PeruvianSigmatostalix, and PeruvianStenia. Solenidium (Solenidiopsis) peruvianum Schltr. is lectotypified.     

Phylogeny of cardinalfishes (Teleostei: Gobiiformes: Apogonidae) and the evolution of visceral bioluminescence

The cardinalfishes (Apogonidae) are a diverse clade of small, mostly reef-dwelling fishes, for which a variety of morphological data have not yielded a consistent phylogeny. We use DNA sequence to hypothesize phylogenetic relationships within Apogonidae and among apogonids and other acanthomorph families, to examine patterns of evolution including the distribution of a visceral bioluminescence system. In conformance with previous studies, Apogonidae is placed in a clade with Pempheridae, Kurtidae, Leiognathidae, and Gobioidei. The apogonid genus Pseudamia is recovered outside the remainder of the family, not as sister to the superficially similar genus Gymnapogon. Species sampled from the Caribbean and Western Atlantic (Phaeoptyx, Astrapogon, and some Apogon species) form a clade, as do the larger-bodied Glossamia and Cheilodipterus. Incidence of visceral bioluminescence is found scattered throughout the phylogeny, independently for each group in which it is present. Examination of the fine structure of the visceral bioluminescence system through histology shows that light organs exhibit a range of morphologies, with some composed of complex masses of tubules (Siphamia, Pempheris, Parapriacanthus) and others lacking tubules but containing chambers formed by folds of the visceral epithelium (Acropoma, Archamia, Jaydia, and Rhabdamia). Light organs in Siphamia, Acropoma, Pempheris and Parapriacanthus are distinct from but connected to the gut; those in Archamia, Jaydia, and Rhabdamia are simply portions of the intestinal tract, and are little differentiated from the surrounding tissues. The presence or absence of symbiotic luminescent bacteria does not correlate with light organ structure; the tubular light organs of Siphamia and chambered tubes of Acropoma house bacteria, those in Pempheridae and the other Apogonidae do not.     

Biological control of three floating water weeds,<Emphasis Type="Italic">Eichhornia crassipes,Pistia stratiotes</Emphasis>, and <Emphasis Type="Italic">Salviniamolesta</Emphasis> in the Republic of Congo

Since 1999, four specific weevils (Coleoptera, Curculionidae) were released in the Republic of Congo against three exotic floating water weeds: Neochetina eichhorniae Warner and N. bruchi Hustache against water hyacinth, Neohydronomus affinis Hustache against water lettuce, and Cyrtobagous salviniae Calder and Sands against water fern. Recoveries of exotic weevils were made from all 24 release sites except one, and all four species have established and spread (up to 800 km for water hyacinth weevils). Within a few years of releases, control of water fern and water lettuce was such that fishing and navigation could be resumed, while reductions of water hyacinth populations were only beginning.     

Taxonomic status of the species of the green algal genusNeochloris

Komárek has recently reviewed the various species assigned to the green algal genusNeochloris Starr (Chlorococcales, Chlorococcaceae) and removed those with uninucleate vegetative cells to a new genus,Ettlia. Watanabe & Floyd, unaware ofKomárek's work, also reviewed the species ofNeochloris and distributed them among three genera—Neochloris, Chlorococcopsis gen. nov., andParietochloris gen. nov.—on the basis of details of the covering of the zoospore and the arrangement of the basal bodies of the flagellar apparatus. This paper reconciles these two treatments and makes additional recommendations at the ranks of genus, family, order, and class.     

Phylogenetic investigations of Sordariaceae based on multiple gene sequences and morphology

The family Sordariaceae incorporates a number of fungi that are excellent model organisms for various biological, biochemical, ecological, genetic and evolutionary studies. To determine the evolutionary relationships within this group and their respective phylogenetic placements, multiple-gene sequences (partial nuclear 28S ribosomal DNA, nuclear ITS ribosomal DNA and partial nuclear β-tubulin) were analysed using maximum parsimony and Bayesian analyses. Analyses of different gene datasets were performed individually and then combined to generate phylogenies. We report that Sordariaceae, with the exclusion Apodus and Diplogelasinospora, is a monophyletic group. Apodus and Diplogelasinospora are related to Lasiosphaeriaceae. Multiple gene analyses suggest that the spore sheath is not a phylogenetically significant character to segregate Asordaria from Sordaria. Smooth-spored Sordaria species (including so-called Asordaria species) constitute a natural group. Asordaria is therefore congeneric with Sordaria. Anixiella species nested among Gelasinospora species, providing further evidence that non-ostiolate ascomata have evolved from ostiolate ascomata on several independent occasions. This study agrees with previous studies that show heterothallic Neurospora species to be monophyletic, but that homothallic ones may have a multiple origins. Although Gelasinospora and Neurospora are closely related and not resolved as monophyletic groups, there is insufficient evidence to place currently accepted Gelasinospora and Neurospora species into the same genus.     

A molecular phylogeny of Hebeloma species from Europe

In order to widen the scope of existing phylogenies of the ectomycorrhizal agaric genus Hebeloma a total of 53 new rDNA ITS sequences from that genus was generated, augmented by sequences retrieved from GenBank, and analysed using Bayesian, strict consensus and neighbour joining methods. The lignicolous Hebelomina neerlandica, Gymnopilus penetrans, and two species of Galerina served as outgroup taxa. Anamika indica, as well as representatives of the genera Hymenogaster and Naucoria, were included to test the monophyly of Hebeloma, which is confirmed by the results. Hebeloma, Naucoria, Hymenogaster and Anamika indica cluster in a strongly supported monophyletic hebelomatoid clade. All trees largely reflect the current infrageneric classification within Hebeloma, and divide the genus into mostly well-supported monophyletic groups surrounding H. crustuliniforme, H. velutipes, H. sacchariolens, H. sinapizans, and H. radicosum, with H. sarcophyllum being shown at an independent position; however this is not well supported. The section Indusiata divides with strong support into three groups, the position of the pleurocystidiate Hebeloma cistophilum suggests the possible existence of a third subsection within sect. Indusiata. Subsection Sacchariolentia is raised to the rank of section.     

Die GattungKarschia — Bindeglied zwischen bitunicaten Ascomyceten und lecanoralen Flechtenpilzen?

The genusKarschia, in the earlier sense, including saprophytes and parasites on lichens, has been thought to be a non-lichenized parallel genus of the lichen genusBuellia. Modern workers included it on the one hand inBuellia, on the other hand combined it with bitunicate ascomycetes. It is now proved thatKarschia is heterogeneous and contains but superficially similar members both of the genusBuellia of theLecanorales and of typical or masked bitunicateAscomycetes. Therefore, it can not be regarded as a link betweenLecanorales andDothideales. The type species ofKarschia belongs to theDothideales.