豆链格孢菌对白车轴草生理代谢及活性氧清除系统酶的影响

通过盆栽实验,研究了接种豆链格孢菌对白车轴草叶组织细胞膜透性、色素含量、丙二醛(MDA)含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响.结果表明,豆链格孢菌使白车轴草叶组织细胞膜透性上升,电导率显著升高,膜脂过氧化加强,MDA水平上升,色素含量下降.电导率和MDA含量均与感病时间呈显著正相关,而色素含量与感病时间呈显著负相关.豆链格孢菌刺激其寄主白车轴草叶片膜脂过氧化作用发生,积累大量的活性氧,使其超出防御酶的清除能力,致使活性氧清除系统遭到破坏,保护酶系统失衡,其中SOD和CAT活性显著下降,而POD活性明显上升.接种12d后,SOD和CAT分别降低了55.2%和37.8%,而POD比对照升高约1.6倍.     

低温弱光对辣椒幼苗抗氧化酶活性与质膜透性的影响

以辣椒CapsicumannuumL.幼苗为材料,研究了辣椒幼苗叶片中活性氧清除系统对低温弱光的响应.结果表明:随着低温弱光胁迫程度和时间的增加,辣椒幼苗叶片中POD活性提高,但SOD和CAT活性下降,MDA含量增加,细胞膜透性增大;就温度而言,临界低温15℃/8℃比偏低温19℃/12℃对植株的影响更为显著;在偏低温19℃/12℃下,弱光90μmol·m-2·s-1使POD活性上升更大,而SOD和CAT活性的下降、MDA含量的增加和细胞膜透性的增大更小,而在临界低温15℃/8℃下则相反;陇椒2号耐低温弱光能力强,各项指标均优于七寸红.     

化学催熟剂对油菜角果叶绿素含量及抗氧化酶系统的影响

采用大田试验研究了两种化学催熟剂（敌草快和农达）对生长后期油菜角果的叶绿素含量、抗氧化酶系统（CAT、SOD、POD活性）、细胞膜透性及MDA含量的影响.结果表明：采用敌草快催熟,油菜角果皮叶绿素含量下降,SOD、POD、CAT活性及细胞膜透性和MDA含量显著提高,导致角果膜脂过氧化,且作用强度随处理浓度的增加而增加;采用农达催熟,油菜角果皮叶绿素含量所受影响较小,SOD、POD和CAT活性上升缓慢,细胞膜透性和MDA含量增加不明显.随着催熟时间的推移,油菜角果保护酶活性受到不同程度的抑制,这可能与催熟剂干扰酶系统分子结构有关.     

不同光照强度下豆链格孢菌对白车轴草生理生化特性的影响

通过盆栽实验研究了不同光照强度下,接种豆链格孢菌(Alternariaazukiae(hara)comb.nov)对白车轴草(TrifoliumrepensL.)叶组织细胞膜透性、色素含量、丙二醛(MDA)含量、蛋白质含量、脯氨酸含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性的影响。结果表明:豆链格孢菌使白车轴草叶组织细胞膜透性上升,电导率显著升高,膜脂过氧化加强,MDA水平上升,色素含量、蛋白质含量以及脯氨酸含量下降。随着处理光照强度的减弱,以上各生理指标的变化趋势更为明显,电导率和MDA含量均与光照强度显著负相关,而色素含量、蛋白质含量及脯氨酸含量均与光照强度显著正相关。接种豆链格孢菌后,色素含量明显下降,且弱光下(75%遮阳),豆链格孢菌对白车轴草叶片色素含量的影响更为明显,对照组的叶绿素a、叶绿素b、叶绿素(a b)和类胡萝卜素含量均显著高于接种组的色素含量。在豆链格孢菌的刺激下,活性氧清除系统遭到破坏,保护酶系统失衡,其中SOD和CAT活性显著下降,而POD活性却明显上升,并且SOD、POD和CAT三种酶活性均与光照强度存在着明显的负相关系。     

外源芦丁预处理对水分胁迫下玉米幼苗的生理效应

以玉米(Zeamays L.)品种'郏单958'为材料.采用营养液水培法,研究了外源芦丁(Rutin)对聚乙二醇(PEG)胁迫下幼苗叶片质膜相对透性、脯氨酸、可溶性糖含量及保护酶活性的影响.结果显示:(1)在15%PEG-6000胁迫下,玉米叶片的MDA含量、质膜相对透性、脯氨酸和可溶性蛋白质含量均显著增加,保护酶SOD、CAT、POD活性显著升高.(2)一定浓度芦丁(>0.40 g/L)预处理可显著抑制水分胁迫下玉米幼苗叶片MDA含量的上升,降低叶片质膜相对透性,并诱导SOD、POD和CAT活性提高.降低脯氨酸和可溶性蛋白质含量.说明外源芦丁能够提高玉米幼苗的抗氧化作用,缓解水分胁迫引起的膜脂过氧化,保护细胞膜免受或减少损伤·达到提高植物抗旱性的目的.     

低温胁迫下不同光照条件对锦熟黄杨抗氧化酶活性的影响

研究了锦熟黄杨（Buxus sempervirens L.）在低温胁迫下不同光照条件（12 h光照/12 h黑暗、24 h全光、24 h全黑）对其抗氧化酶活性的影响,结果表明：低温不同光照条件下细胞膜透性和丙二醛含量均高于对照（20℃ 12 h光照/12 h黑暗）,细胞膜透性和丙二醛含量在5℃ 24 h光照条件下最大;低温胁迫下SOD活性高于对照,并在5℃ 24 h光照条件下达到最高值;CAT的活性仍维持较高水平,5℃ 12 h光照/12 h黑暗显著高于对照及其它处理;在低温有光照条件下,POD活性升高,黑暗条件下POD活性低于对照。低温胁迫下POD、SOD和CAT的活性均呈上升趋势,可能是植株具有较强抗性的原因。     

α-NAA和UV-B辐射对栝楼幼苗光合色素及保护酶活性的影响

温室条件下研究 UV- B辐射 ( 0 .0 2 9J/( m2·s) )和外施 α-萘乙酸 ( α- NAA) ( 2 mg/L)对栝楼叶片光合色素及保护酶活性的影响。实验结果表明 :外施α- NAA,能提高栝楼幼苗叶片叶绿素及类胡萝卜素的含量 ,提高保护酶 SOD、CAT、POD、ASP的活性 ,细胞膜相对透性和膜脂过氧化产物 MDA含量相对稳定。UV- B辐射单独处理 ,则极显著地降低叶绿素 a的含量 ,叶绿素 b含量也呈明显地下降趋势 ,类胡萝卜素含量稍有下降 ,极显著降低栝楼幼苗叶片 SOD、POD、CAT、ASP活性 ,引起细胞膜相对透性明显增大 ,MDA含量显著增加。α- NAA与 UV- B辐射共同处理栝楼幼苗 ,与 UV- B辐射处理相比 ,叶绿体色素含量都有不同程度增加 ,而细胞膜相对透性、MDA含量则有不同程度降低 ,SOD、POD、ASP活性上升 ,CAT活性显著上升。以上结果暗示 ,UV- B辐射对生长的影响可能是 :( 1 )破坏光合色素而导致光合能力下降 ;( 2 )降低保护酶 SOD、POD、CAT、ASP活性 ,导致膜脂过氧化 ,膜结构遭到破坏 ,膜透性增加。而外施α- NAA,能部分减轻由增强的 UV- B辐射对栝楼幼苗造成的这种伤害 ,其原因可能是 α- NAA提高了保护酶活性 ,维持了活性氧产生与清除之间的平衡 ,即是维持了膜结构的稳定性。可见 ,α- NAA能增加栝楼对 UV- B辐射的抗性。     

丛枝菌根真菌对柑橘嫁接苗枳/红肉脐橙抗旱性的影响

采用盆栽试验,研究了自然水分胁迫和胁迫解除复水条件下接种AM真菌摩西球囊霉对柑橘嫁接苗枳/红肉脐橙生长和保护系统能力的影响.结果表明,接种AM真菌的柑橘嫁接苗的株高、穗粗、叶面积和新梢生长量显著或极显著地高于未接种植株.在胁迫解除复水第4天,接种AM真菌的根系可溶性蛋白质含量、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性显著或极显著高于未接种植株.在自然水分胁迫和胁迫解除复水过程中,接种AM真菌较未接种处理降低叶片丙二醛(MDA)含量,提高可溶性糖和可溶性蛋白质含量,增强SOD、过氧化物酶(POD)、CAT活性,从而增强柑橘嫁接苗的渗透调节和保护防御能力,提高柑橘嫁接苗的抗旱能力.水分和菌根显著交互影响叶片SOD活性.AM真菌提高寄主植物的抗旱性机制可能与寄主植物的保护系统能力的改变有关.     

钙对低温胁迫的烟草幼苗某些酶活性的影响

用CaCl2 浸种处理烟草种子 ,研究了钙对烟草幼苗某些酶活性的影响。结果表明 :CaCl2 浸种能够提高烟草幼苗结合态钙和膜保护酶活性 ,降低膜透性和MDA(丙二醛 )含量。在低温胁迫条件下 ,Ca2 浸种处理的烟草幼苗SOD、CAT和POD等保护酶活性下降程度较未经处理的轻 ,细胞相对电导率低。恢复生长后 ,幼苗膜透性和保护酶活性恢复较快。CaM(钙调素 )特异性抑制剂CPZ(氯丙嗪 )能部分抑制Ca2 提高SOD、CAT和POD活性的作用     

丛枝菌根真菌对低温下黄瓜幼苗光合生理和抗氧化酶活性的影响

作者于塑料连栋大棚栽培条件下,研究了接种丛枝菌根真菌(AMF)Glomus mossea-2对低温下黄瓜(Cucumis sativus L.)幼苗同化产物积累、光合生理和过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物歧化酶(SOD)、抗坏血酸过氧化物酶(APX)的活性及基因表达的影响。结果表明：低温显著抑制了AMF对黄瓜根系的侵染能力和菌根相对依赖性。接菌后30d—45d AMF为快速侵染期。接种AMF植株的鲜重根冠比、总干重、总鲜重均显著大于未接菌处理。低温胁迫下,接种AMF延缓了光合速率、根系活力、羧化效率和叶绿素、可溶性蛋白含量的下降,并且使丙二醛(MDA) 的含量保持相对较低的水平,诱导了抗氧化酶基因的表达及活性提高。接种AMF可以使叶片维持较高的抗氧化酶水平和光合能力,增强了对低温胁迫的抗性。 关键词：黄瓜;丛枝菌根真菌;低温;抗氧化酶     

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.     

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.     

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.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

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.     

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.     

安徽牯牛降的丝孢菌Ⅰ

本文报导作者采自安徽枯牛降自然保护区的18种丝孢菌,分属于5个属,其中有3个新种:牛皮冻生尾孢(Cercospora paederiicola),山鸡椒假尾饱(Pseudocercospora litseae-cubebae),鸡血藤生假尾孢(P. millettiicola)和2个中国新纪录。文中对新种进行了描述及绘图,新记录种作了简要说明。研究的标本保存在中国科学院微生物研究所真菌标本室(HMAS)。     

Changes of dung beetle communities from rainforests towards agroforestry systems and annual cultures in Sulawesi (Indonesia)

Little is known about how tropical land-use systems contribute to the conservation of functionally important insect groups, including dung beetles. In a study at the margin of Lore Lindu National Park (a biodiversity hotspot in Central Sulawesi, Indonesia) dung-beetle communities were sampled in natural forest, young secondary forest, agroforestry systems (cacao plantations with shade trees) and annual cultures (maize fields), each with four replicates (n = 16 sites). At each site we used 10 pitfall traps, baited with cattle dung, along a 100 m transect for six 3-day periods. The number of trapped specimens and species richness at the natural forest sites was higher than in all land-use systems, which did not significantly differ. Each land-use system contained, on average, 75% of the species richness of the natural forest, thereby indicating their importance for conservation. However, a two-dimensional scaling plot based on NESS indices (m = 6) indicated distinct dung beetle communities for both forest types, while agroforestry systems and annual cultures exhibited a pronounced overlap. Mean body size of dung beetles was not significantly influenced by land-use intensity. Five of the six most abundant dung beetle species were recorded in all habitats, whereas the abundance of five other species was significantly related to habitat type. Mean local abundance and number of occupied sites were closely correlated, further indicating little habitat specialisation. The low dung beetle diversity (total of 18 recorded species) may be due to the absence of larger mammals in Sulawesi during historical times, even though Sulawesi is the largest island of Wallacea. In conclusion, the dung beetle fauna of the lower montane forest zone in Central Sulawesi appears to be relatively robust to man-made habitat changes and the majority of species did not exhibit strong habitat preferences.     

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.