伊乐藻(Elodea nuttallii)对高浓度氮磷营养盐的耐受性

通过5个相对恒定的TN、TP浓度梯度下伊乐藻(Elodea nuttallii)的生长实验,探讨了伊乐藻对高浓度氮磷营养盐的耐受性,比较了各营养盐浓度下水体的pH值、DO、浮游藻类叶绿素a和附着藻类叶绿素a以及伊乐藻的株高、湿质量、干质量和叶绿素a含量.结果表明:在实验条件下,伊乐藻能耐受TN=10 mg·L~(-1),TP=0.4 mg·L~(-1)的胁迫,且在该营养盐水平下水体中没有出现大量的浮游藻类;而在TN=50 mg·L~(-1)、TP=2 mg·L~(-1)和TN=100 mg·L~(-1)、TP=4 mg·L~(-1)的高营养盐条件下,伊乐藻的生长受到了明显的抑制,同时水体中的浮游藻类明显增多,而附着藻类则明显减少;在高营养盐水平下,一方面水体中的某些营养盐可能对伊乐藻产生了直接伤害,另一方面水体中浮游藻类的增多,所导致的遮光作用也可能限制了其生长;对水体中营养盐的平均水平低于TN=10 mg·L~(-1),TP=0.4 mg·L~(-1)的太湖而言,沉水植被的消亡可能不是由于氮磷营养盐所产生的直接伤害和胁迫.     

牧食损害对伊乐藻(Elodea nuttallii)生长的影响

在室外实验条件下,研究了模拟牧食损害(动物牧食所造成的损害)对伊乐藻植株生长的影响。结果表明:3种人工损害方式(去除植株50%叶片,去除植株顶端,以及同时去除植物顶端与50%叶片)对伊乐藻的生长率、主枝与分枝长度的增长、植物的干物质、氮、磷含量等均有不同程度的影响。其中,去叶与去顶去叶损害显著抑制了伊乐藻的生长,相对生长率分别占未受损植株的62.8%与74.4%;去顶与去顶去叶损害使伊乐藻主枝生长几乎停止,却显著促进了植物分枝的生长;去叶损害对植株的生长率、主枝与分枝长度的生长无明显抑制并却显著地降低了分枝的重量。对受损伊乐藻生长的机理进行了分析,探讨了东太湖伊乐藻现存量近年来迅速增加的原因并认为植物残体是伊乐藻种群扩张的重要因素之一。     

牧食损害对伊乐藻(Elodea nuttallii)生长的影响

在室外实验条件下,研究了模拟牧食损害（动物牧食所造成的损害）对伊乐藻植株生长的影响。结果表明：3种人工损害方式（去除植株50%叶片,去除植株顶端,以及同时去除植物顶端与50%叶片）对伊乐藻的生长率、主枝与分枝长度的增长、植物的干物质、氮、磷含量等均有不同程度的影响。其中,去叶与去顶去叶损害显著抑制了伊乐藻的生长,相对生长率分别占未受损植株的62.8%与74.4%;去顶与去顶去叶损害使伊乐藻主枝生长几乎停止,却显著促进了植物分枝的生长;去叶损害对植株的生长率、主枝与分枝长度的生长无明显抑制并却显著地降低了分枝的重量。对受损伊乐藻生长的机理进行了分析,探讨了东太湖伊乐藻现存量近年来迅速增加的原因并认为植物残体是伊乐藻种群扩张的重要因素之一。     

重要环境因子对小球藻去除污水中氮磷的影响

对小球藻去除污水中氮磷的性能进行了研究,考察了初始氮磷浓度、氮磷比、光照条件和pH等因素对其去除效率的影响。结果表明,在初始氮磷浓度分别在35 mg/L和7 mg/L以下时去除率接近100%;氮磷比为5∶1和10∶1,小球藻第4 d基本完全去除了污水中的氨态氮,而氮磷比对小球藻的除磷能力没有显著影响;在初始氨态氮或总磷浓度相同的条件下,光照条件(L/D为24 h∶0 h和12 h∶12 h)对氮磷去除效果的无明显差异性（P＞0.05）,而随着氮磷浓度的增加,连续光照条件逐渐展现出去除氮磷的优势;小球藻在pH 7～8范围内对氨态氮的去除率最佳,pH 5～7范围内,对总磷的去除率最佳。     

不同氮磷浓度下周丛生物对水体中磺胺和恩诺沙星的去除

周丛生物膜是一种对水体污染物净化的新兴生物技术。有关水体不同氮磷营养水平下周丛生物对水体抗生素类污染物去除作用的研究还未见报道。本研究设置4个氮磷营养盐浓度水平[N-P (mg·L^-1):2-0.2、5-0.5、8-0.8、11-1.1],用塑料筐装置在室外培养周丛生物膜,对其生长、光合活力、物种组成以及对磺胺和恩诺沙星去除作用进行中型模拟试验。结果表明: 各处理组中周丛生物的生物量随培养时间的增加而升高,光合色素含量和光合活力则呈现先降低后上升的“单峰”模式,表明生物膜中的藻类会受到抗生素的胁迫,但可快速适应并恢复活力。除此之外,不同氮磷浓度处理造成各组生物群落组成差异,随营养盐浓度的升高,周丛藻类物种丰富度逐渐下降,但各处理胶网藻和小球藻都具有较高的相对丰度;16S rRNA高通量测序发现,根瘤菌科、放线菌门和莫拉氏菌科菌群在(N-P)2-0.2组显著富集,而几丁质嗜菌科在4个处理中的相对丰度都处在最高水平。所有处理的磺胺去除率均高于50%,而恩诺沙星去除率均达到90%以上,其中,(N-P)2-0.2 mg·L^-1组对磺胺的去除率(65.8%)显著高于其他各组,但各处理对恩诺沙星的去除率差异不显著,表明周丛生物在较宽的N-P营养水平范围内对磺胺和恩诺沙星均具有良好的去除能力。各处理组对水体可溶性氮的去除效果不明显,但对可溶性磷的去除效果显著。本研究为水体磺胺和恩诺沙星的生态去除提供了基础数据,为研发水体抗生素类新型污染物生态去除技术提供了新思路。     

不同营养条件对金鱼藻净化作用及其生理生态的影响

以沉水植物金鱼藻（Ceratophyllum demersum）为研究对象,研究了较高营养条件（N:1030 mg/L,P:13 mg/L）对金鱼藻去除氮、磷能力的影响,金鱼藻的含磷量、生物量与净光合作用速率对营养负荷的响应。结果表明,金鱼藻-沉积物处理系统可有效去除氮、磷（去除率80%以上）,但去除效率随水中营养盐浓度的升高而下降。试验结束时各试验组金鱼藻总磷含量达7.0113.09 mg/g （平均9.03 mg/g）,显著高于对照组（2.853.17 mg/g,平均3.05 mg/g）,表明金鱼藻可以吸收水体中的磷。营养盐对金鱼藻生长有明显抑制,其抑制作用随营养盐浓度增高而加剧,除对照组外,各试验组金鱼藻均有叶片脱落,试验结束时金鱼藻生物量降至初始生物量的48.3%63.3%。在较高营养水体中,金鱼藻的净光合作用速率由试验开始时-0.0370.058 mg/（gh）显著上升至试验结束时0.180.44 mg/（gh）,而对照组变化不大,这表明在试验后期,随着水体营养盐浓度降低,金鱼藻开始进行恢复性生长,说明水体营养盐浓度对金鱼藻的净光合作用速率和生长速率有明显影响。金鱼藻尚不适宜作为滇池草海生态修复的先锋物种。       

毛枝藻对人工污水脱氮除磷能力的研究

文章探究了2株毛枝藻(Stigeoclonium sp.)SHY-370及HB1617在不同初始氨氮浓度以及不同氮磷比条件下的生长情况与氮磷去除能力。结果表明氨氮浓度对2株毛枝藻的生长及TP去除能力均有一定的影响, SHY-370可耐受最大氨氮浓度为10 mg/L, HB1617为5 mg/L;氨氮浓度为1—10 mg/L时SHY-370及HB1617对其去除率均达到97%以上,最大去除速率为3.98 mg/(L·d)。氮磷比对SHY-370的生长影响不大,但在氮磷比大于20时HB1617的生长受到抑制; SHY-370对NO_3~--N去除的最佳氮磷比为10—40, HB1617为2—10;氮磷比为2时水体中TP的含量超过了SHY-370及HB1617所能去除的最大值,去除率较低。实验结果表明SHY-370及HB1617在污水深度脱氮除磷方面具有一定的潜力,可考虑将其应用于城市生活污水二级出水(TN≤15 mg/L、TP≤0.5 mg/L、 NH_4~+-N≤5 mg/L)的深度处理。     

利用Chlorella vulgaris C9-JN2010去除蓝藻-猪粪沼液废水中氮磷的研究

利用普通小球藻Chlorella vugaris C9-JN2010处理蓝藻-猪粪沼液废水,以实现废水无害化利用。实验考察了氮磷比和沼液浓度对小球藻生长及处理废水效果的影响,结果表明:在氮磷比(20:1)和沼液浓度(5%)条件下培养小球藻,藻细胞生长和废水处理效果最佳,最高细胞干重及生产强度分别为900.1 mg·L~(-1)和85.1 mg·L~(-1)·d~(-1),废水中总氮、总磷、氨氮的去除率分别为84.6%、95.9%和90.5%,对应去除强度分别为5.43 mg·L~(-1)·d~(-1)、0.30 mg·L~(-1)·d~(-1)和4.75 mg·L~(-1)·d~(-1)。利用小球藻可较彻底的去除蓝藻-猪粪沼液废水中氮、磷等营养,达到污水处理效果。     

漂浮植物对富营养化水体中氮磷去除效果研究

通过模拟不同程度富营养化水体,研究凤眼莲、水芙蓉和莲花竹在不同处理浓度水体中对氮、磷的去除效果。结果表明:凤眼莲、水芙蓉和莲花竹对水体中的氮、磷都有一定的去除效果,经过30 d的净化试验,凤眼莲对氮、磷去除率分别为50%~78.46%和68.16%~89.56%,水芙蓉对氮、磷去除率分别为57.58%~76.87%和72.28%~76.47%,莲花竹对氮、磷去除率分别为0.60%~10.80%和2.48%~10.04%。在现场试验中,水体中总氮和总磷分别降低了31.17%和20.48%,由此可见,凤眼莲和水芙蓉对氮、磷有较好的去除效果,能够改善富营养化水体。     

钝顶螺旋藻SP1(Spirulina platensis)对集约化养殖尾水氮磷的去除效果

针对集约化养殖模式后期硝酸盐氮和磷酸盐浓度较高的问题, 实验设置生物絮团养殖尾水(BFW)和BG11培养液(BGW)两种水体环境, 并以池塘常见优势微藻--绿色颤藻OC1(Oscillatoria chlorina)作为对比, 研究分析了钝顶螺旋藻SP1(Spirulina platensis)对集约化养殖尾水氮磷的去除效果及其生长状况。结果发现, 在BFW组中两种微藻均对硝酸盐氮(NO3--N)、总无机氮(TIN)和磷酸盐(PO43--P)去除效果明显(P<0.05), 其中, 螺旋藻对NO3--N、TIN和PO43--P的最大去除率分别为79.60%、46.06%和98.55%, 相应的浓度值分别从130.04 mg·L-1、130.85 mg·L-1和10.23 mg·L-1降至26.53 mg·L-1、70.58 mg·L-1和0.15 mg·L-1,其数量降低的绝对值分别为103.51 mg·L-1、60.27 mg·L-1、10.08 mg·L-1; 在BGW组中两种藻对氮磷均具有一定的去除效果, 但总体仍低于BFW组。实验过程中两种微藻的细胞数量均无明显变化(P>0.05)。可见, 钝顶螺旋藻SP1和绿色颤藻OC1均可在BFW和BGW两种水体营养环境下存活, 且对水中的氮磷均有良好的去除效果; 虽然颤藻亦是集约化养殖水环境中的常见微藻优势种, 但它能分泌蓝藻毒素, 因此, 从产业应用的可行性考虑可将螺旋藻作为集约化养殖尾水净化的备选藻株。     

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.     

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.     

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.

     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

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.     

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.