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1.
研究了菊科向日葵族鳢肠亚族蟛蜞菊属(Sphagneticola O. Hoffm.)和孪花菊属(Wollastonia DC. ex Decne.)各2种植物的染色体数目和染色体形态。蟛蜞菊[S. calendulacea (L.) Pruski]的染色体数目为2n=50, 核型公式为2n=18m+30sm+2st,南美蟛蜞菊[S. trilobata (L.) Pruski]的染色体数目为2n=56, 核型公式为2n=24m+28sm+4st, 孪花菊[W. biflora (L.) DC.]的染色体数目为2n=30,核型公式为2n=24m+4sm+2st,山孪花菊[W. montana (Blume) DC.]的染色体数目为2n=74, 核型公式为2n=37m+31sm+6st。根据上述结果并结合以前的有关资料,推测蟛蜞菊属的染色体基数可能为x=14和x=25,而不应是x=15。该属的3个新世界热带种[S. brachycarpa (Baker) Pruski、S. gracilis (Richard) Pruski和南美蟛蜞菊]可能都基于x=14, 其中S. gracilis为二倍体(2n=2x=28), S. brachycarpa和南美蟛蜞菊为四倍体(2n=4x=56); 唯一的亚洲种(蟛蜞菊)可能是基于x=25的二倍体(2n=2x=50)。染色体资料不支持将山孪花菊(x=37)这一植物置于孪花菊属(x=15)中。  相似文献   

2.
描述了产自江西的兰科(Orchidaceae)虾脊兰属(Calanthe R. Br.)植物一新变型——异钩距虾脊兰 (Calanthe graciliflora f. jiangxiensis B. Li, L. J. Kong et B. Y. Yang),并绘制了线条图。该新变型与原变型钩距虾脊兰(C. graciliflora Hayata)的主要区别为距末端分裂为2个不等的短尖。  相似文献   

3.
比较了安龙花(Dyschoriste sinica H. S. Lo)的模式标本与距药花属(Dyschoriste Nees)和马蓝属(Strobilanthes Bl.)部分种类的花粉和花的特征后,支持将安龙花转移到马蓝属,组合为Strobilanthes sinica (H. S. Lo) Y. F. Deng。安龙花隶属于马蓝属黄猄草群,它与日本马蓝(Strobilanthes japonica (Thunb.) Miq.)近似,但区别在于它的匍匐习性,叶矩圆状椭圆形,近无柄,花单生叶腋。因此,距药花属(Dyschoriste Nees)在中国并没有分布。  相似文献   

4.
采用TAIL-PCR技术从箭叶淫羊藿(Epimedium sagittatum)叶片中克隆得到查耳酮合成酶基因(Chalcone synthase)的启动子,命名为ECHSP, 长度为750 bp,其具有TATA BOX、CAAT BOX、MYB结合位点、MYC结合位点等元件。对箭叶淫羊藿、木鱼坪淫羊藿(E. franchetii)、粗毛淫羊藿(E. acuminatum)、直距淫羊藿(E. mikinorii)、黔岭淫羊藿(E. leptorrhizum)等5种植物的CHS启动子序列进行比较分析,结果表明,CHS启动子的核苷酸多态性丰富,表明CHS 的表达可能受到多种因素的灵活调节。ECHSP与其他植物的CHS启动子序列进行比较,其TATA box的位置可能与黄酮类化合物的积累相关。此外,进化分析表明ECHSP的核苷酸序列可应用于淫羊藿属植物的系统进化研究。  相似文献   

5.
燕麦属不同倍性种质资源抗旱性状评价及筛选   总被引:4,自引:0,他引:4  
盆栽控水试验测定了燕麦属13个二倍体、7个四倍体和5个六倍体物种共106份材料的主要抗旱性状表现,用GGEbiplot软件的主成分分析法比较了各性状之间的关系及其对抗旱鉴定的贡献,综合评价燕麦属野生资源在燕麦抗旱育种中的潜能和利用价值。结果表明,干旱处理后植株的死亡率和萎蔫程度与可溶性糖含量的增加幅度呈显著正相关关系(r>0.5, P<0.05),而胁迫后植株的丙二醛(MDA)含量和植株相对电导率与抗旱能力也明显相关(r>0.5, P<0.01)。综合考虑抗旱的相关形态和生理指标,筛选到二倍体Avena atlanticaA. wiestii A. strigosa,四倍体种A. murphyi,以及六倍体栽培燕麦A. sativa和普通野燕麦A. fatua的部分居群具有优良的综合抗旱性。基于A. wiestii,A. strigosaA. murphyi与栽培燕麦较近的亲缘关系,其抗旱性可通过远缘杂交的方式在普通燕麦育种中加以利用。而对于具有明显抗旱优势的野生二倍体材料A. atlantica,则可通过克隆其抗旱基因进而遗传转化的方法将其应用于栽培燕麦的抗旱性改良。同时该研究表明燕麦的抗旱性不具有种属和分布区域的特异性,因此其抗旱性并非简单的由基因或环境决定,在确定抗旱材料时需要对个体进行全面的抗旱性评价和鉴定,以期在利用抗旱材料或通过克隆抗旱基因来改善干旱地区生态环境的实践中能更准确和有效。  相似文献   

6.
从陆地革菌(Thelephora terrestris)子实体中分离得到9个已知化合物,经波谱学分析鉴定为:(22E,24R)-麦角甾-7,22-二烯-3β -醇 (1),(22E, 24R)-麦角甾-7, 22-二烯-3β ,5α,6β -三醇 (2),(22E,24R)-麦角甾-4,6,8(14),22-四烯-3-酮 (3),24-亚甲基羊毛甾-8-烯-3β -醇 (4),熊果酸 (5),木栓酮 (6),cerebroside B (7),(2S,3S,4R,2'R)-2-(2'-羟基二十二碳酰氨基)-十八碳烷-1,3,4-三醇 (8),(2S,3S,4R,2'R)-2-(2'-羟基二十三碳酰氨基)-十八碳烷-1,3,4-三醇 (9)。  相似文献   

7.
粗壮光叶拟单性木兰(Magnolia nitida var. robusta)被转移到拟单性木兰属(Parakmeria),升级为种的等级。它与光叶拟单性木兰不同,特征是:长叶片,长叶柄,雌蕊短于雄蕊,花两性或雄性,被片乳白色,附属物尖 (3~3.5 mm)。  相似文献   

8.
报道中国茜草科(Rubiaceae)玉叶金花属一新记录种——长瓣玉叶金花(Mussaenda longipetala H. L. Li)。该种在形态上与尾裂玉叶金花(M. caudatiloba D. Fang)和狭瓣玉叶金花(M. lancipetal X. F. Deng & D. X. Zhang)相似,但区别在于叶片长圆状卵形或椭圆状卵形,托叶早落,正常的萼裂片长6~8 mm,花冠管长约3 cm,裂片披针形,长约12 mm。目前仅知分布于越南北部的广宁省和中国的广西北部湾沿海地区。凭证标本存放于广西植物标本馆(IBK)。  相似文献   

9.
提出一新组合——短穗观音草(Peristrophe brevispicata (I. Darbysh.) Y. F. Deng et Z. P. Hao)。  相似文献   

10.
黄增玉  黄林茂  黄寿山 《生态学报》2011,31(10):2947-2952
南方小花蝽(半翅目:花蝽科)是农田害虫的重要天敌之一。在室内,分别用米蛾卵和二斑叶螨饲养南方小花蝽,采用生命表与功能反应方法,探讨了两种猎物(米蛾卵、二斑叶螨)对南方小花蝽种群增长的影响、评价了南方小花蝽应用前景。南方小花蝽取食米蛾卵的年龄特征生命表的参数如下:世代平均历期T= 24.3500d,雌性比率P=0.5250,单雌平均产卵量FPF=37.2857头,种群趋势指数(I)=9.2118,周限增长率λ=1.0955,内禀增长率rm=0.0912。取食二斑叶螨的南方小花蝽能完成发育,雌雄可交配,但不能产卵。一龄若虫的存活率为81.19%,低于其它龄期的若虫存活率(89.5%以上)。从初孵若虫至成虫死亡,平均历期为19.3716d。取食米蛾卵的南方小花蝽成虫存活率为83.33%,而取食二斑叶螨的成虫存活率为59.68%;取食米蛾卵的南方小花蝽若虫平均历期(11.0633d)短于取食二斑叶螨的(13.8950d);然而取食米蛾卵的南方小花蝽成虫平均历期(9.9750d)明显长于取食二斑叶螨的(5.7297d)。表明米蛾卵能够满足南方小花蝽生长发育的营养需求,可以用来室内饲养南方小花蝽,二斑叶螨室内不能单独用于饲养南方小花蝽。南方小花蝽成虫对二斑叶螨成螨捕食功能反应符合HollingⅡ模型,且处置时间Th=0.0108,瞬间攻击率a=0.8253,日最大捕食量Namax =92.59 d-1。南方小花蝽是二斑叶螨潜在的生物防治资材。  相似文献   

11.
12.
Ten species of stylet-bearing nematodes were recovered in a survey of sycamore (Platanus occidentalis L. ) stands in Georgia. Helicotylenchus, Xiphinema, and Criconemoides were the genera found most frequently. Populations of Hoplolaimus galeatus, Scutellonema brachyurum, Helicotylenchus dihystera and H. pseudorobustus increased on greenhouse-grown sycamore, but Trichodorus christiei, Xiphinema americanum, Meloidogyne hapla, M. arenaria and M. incognita did not. Hoplolaimus galeatus and S. brachyurum are semi-endoparasites; H. dihystera and H. pseudorobustus are migratory endoparasites. Hoplolaimus galeatus caused extensive root necrosis and marked decrease of fresh weights of seedling roots and tops. Helicotylenchus dihystera and S. brachyurum produced only qualitatively different sparse and unhealthy root growth. Helicotylenchus pseudorobustus caused only a reduction in root surface area.  相似文献   

13.
In the current study, we review the taxonomic status of Liolaemus nigromaculatus. Despite being the nominal species of the nigromaculatus group and being the second species of the genus Liolaemus that was described, this species is of uncertain type locality and its true identification is a matter of discussion. After carefully analyzing several digital pictures of the holotype (juvenile male), reviewing all of the literature concerning the issue, examining specimens of nearly all recognized species of the nigromaculatus group, and determining the locations visited by the specimen collector, we are able to point out the following: 1) Liolaemus nigromaculatus was collected between Puerto Viejo and Copiapó of the Atacama region in Chile, and not in Huasco 2) Liolaemus bisignatus is a nomen nudum, and populations attributed to Liolaemus bisignatus should be referred to as Liolaemus nigromaculatus. 3) There is agreement that Liolaemus copiapoensis is indistinguishable from populations currently referred to as Liolaemus bisignatus (= Liolaemus nigromaculatus), 4) Populations found in Huasco (currently considered the type locality of Liolaemus nigromaculatus) are very similar to those found in Caldera (currently considered Liolaemus bisignatus) and should be designated as Liolaemus nigromaculatus, and 5) Liolaemus oxycephalus and Liolaemus inconspicuus are not synonymous with Liolaemus nigromaculatus, although their true identities are difficult to determine. We also detail several characteristic based on the holotype of Liolaemus nigromaculatus, in addition to drawing diagnostic comparisons between this species and others belonging to the nigromaculatus group.  相似文献   

14.
We dedicate this article to the memory of Sergio de Freitas, FCAV-UNESP, Jaboticabal, São Paulo, Brazil (deceased, 2012). He was an active and enthusiastic Neuropterist and the cherished mentor and friend of Francisco Sosa.Leucochrysa McLachlan is the largest genus in the Chrysopidae, yet it has received relatively little taxonomic attention. We treat two problematic and common Leucochrysa species – Leucochrysa (Leucochrysa) varia (Schneider, 1851) and Leucochrysa (Leucochrysa) pretiosa (Banks, 1910). Both are highly variable in coloration and were described before the systematic importance of chrysopid genitalia was recognized. Recent studies show that these species occur within a large complex of cryptic species and that they have accumulated a number of taxonomic problems. We identify new synonymies for each of the species–for Leucochrysa (Leucochrysa) varia: Leucochrysa (Leucochrysa) ampla (Walker, 1853), Leucochrysa internata (Walker, 1853), and Leucochrysa (Leucochrysa) walkerina Navás, 1913; for Leucochrysa (Leucochrysa) pretiosa: Leucochrysa (Leucochrysa) erminea Banks, 1946. The synonymy of Leucochrysa delicata Navás, 1925 with Leucochrysa (Leucochrysa) pretiosa is stabilized by the designation of a neotype. The following species, which were previously synonymized with Leucochrysa (Leucochrysa) varia or Leucochrysa (Leucochrysa) pretiosa, are reinstated as valid: Leucochrysa (Leucochrysa) phaeocephala Navás, 1929, Leucochrysa (Leucochrysa) angrandi (Navás, 1911), and Leucochrysa (Leucochrysa) variata (Navás, 1913). To help stabilize Leucochrysa taxonomy, lectotypes are designated for Allochrysa pretiosa and Allochrysa variata. Finally, Leucochrysa vegana Navás, 1917 is considered a nomen dubium.  相似文献   

15.
Dark, septate endophytes (DSE) were isolated from roots and needles of dwarf Picea abies and from roots of Vaccinium spp. growing on a permafrost site in the Jura Mountains in Switzerland. Two of the isolates sporulated after incubation for more than one year at 4 °C. One of them was a hitherto undescribed helotialean ascomycete Phaeomollisia piceae gen. sp. nov., the other was a new species of Phialocephala, P. glacialis sp. nov. Both species are closely related to DSE of the Phialocephala fortinii s. lat.-Acephala applanata species complex (PAC) as revealed by phylogenetic analyses of the ITS and 18S rDNA regions. Morphologically dissimilar fungi, such as Vibrissea and Loramyces species, are phylogenetically also closely linked to the new species and the PAC. Cadophora lagerbergii and C. (Phialophora) botulispora are moved to Phialocephala because Phialocephala dimorphospora and P. repens are the closest relatives. Several Mollisia species were closely related to the new species and the PAC according to ITS sequence comparisons. One DSE from needles of Abies alba and one from shoots of Castanea sativa formed Cystodendron anamorphs in culture. Their identical 18S sequences and almost identical ITS sequences indicated Mollisia species as closest relatives, suggesting that Mollisia species are highly euryoecious.  相似文献   

16.
White-nose syndrome (WNS)  of bats, caused by the fungus previously known as Geomyces destructans, has decimated populations of insectivorous bats in eastern North America. Recent work on fungi associated with bat hibernacula uncovered a large number of species of Geomyces and allies, far exceeding the number of described species. Communication about these species has been hindered by the lack of a modern taxonomic evaluation, and a phylogenetic framework of the group is needed to understand the origin of G. destructans and to target closely related species and their genomes for the purposes of understanding mechanisms of pathogenicity. We addressed these issues by generating DNA sequence data for the internal transcribed spacer (ITS) region, nuclear large subunit (LSU) rDNA, MCM7, RPB2, and TEF1 from a diverse array of Geomyces and allies that included isolates recovered from bat hibernacula as well as those that represent important type species. Phylogenetic analyses indicate Geomyces and allies should be classified in the family Pseudeurotiaceae, and the genera Geomyces, Gymnostellatospora, and Pseudogymnoascus should be recognized as distinct. True Geomyces are restricted to a basal lineage based on phylogenetic placement of the type species, Geomyces auratus. Thus, G. destructans is placed in genus Pseudogymnoascus. The closest relatives of Pseudogymnoascus destructans are members of the Pseudogymnoascus roseus species complex, however, the isolated and long branch of P. destructans indicates that none of the species included in this study are closely related, thus providing further support to the hypothesis that this pathogen is non-native and invasive in eastern North America. Several conidia-producing isolates from bat hibernacula previously identified as members of Pseudeurotium are determined to belong to the genus Leuconeurospora, which is widespread, especially in colder regions. Teberdinia hygrophila is transferred to Pseudeurotium as Pseudeurotium hygrophilum, comb. nov., in accordance with the one name per fungus system of classification, and two additional combinations are made in Pseudogymnoascus including Pseudogymnoascus carnis and Pseudogymnoascus pannorum. Additional sampling from other regions of the world is needed to better understand the evolution and biogeography of this important and diverse group of fungi.  相似文献   

17.
Ambrosia beetles (Coleoptera: Scolytinae) are associated with strictly entomochoric and mutualistic fungi. We studied the mycobiota associated with Scolytodes unipunctatus, ambrosia beetles that infest Cecropia trees in Central America. Isolates were characterized using morphology and rDNA sequences (ITS region, LSU, and SSU rDNA). Four species are described here: Raffaelea scolytodis sp. nov. (Ophiostomatales), Gondwanamyces scolytodis sp. nov., Custingophora cecropiae sp. nov., and Graphium sp. (Microascales). The genus Custingophora is emended to include Knoxdaviesia anamorphs of Gondwanamyces based on uniformity of DNA sequences and phenotype.  相似文献   

18.
Notch receptors are expressed in neurons and glia in the adult nervous system, but why this expression persists is not well-understood. Here we examine the role of the Notch pathway in the postnatal mouse main olfactory system, and show evidence consistent with a model where Notch2 is required for maintaining sustentacular cell function. In the absence of Notch2, the laminar nature of these glial-like cells is disrupted. Hes1, Hey1, and Six1, which are downstream effectors of the Notch pathway, are down-regulated, and cytochrome P450 and Glutathione S-transferase (GST) expression by sustentacular cells is reduced. Functional levels of GST activity are also reduced. These disruptions are associated with increased olfactory sensory neuron degeneration. Surprisingly, expression of Notch3 is also down-regulated. This suggests the existence of a feedback loop where expression of Notch3 is initially independent of Notch2, but requires Notch2 for maintained expression. While the Notch pathway has previously been shown to be important for promoting gliogenesis during development, this is the first demonstration that the persistent expression of Notch receptors is required for maintaining glial function in adult.  相似文献   

19.
Species of the genus Dercetina Gressitt & Kimoto, 1963 in Taiwan are revised. Dercetina azumai Gressitt and Kimoto, 1966, Dercetina itoi Kimoto, 1969, and Dercetina shirozui Kimoto, 1969 are redescribed. Dercetina chinensis (Weise, 1889), Dercetina taiwana (Chûjô, 1938), and Dercetina unifasciata (Allard, 1889) are removed from synonymy with Dercetina flavocincta (Hope, 1831). Dercetina flavocincta and Dercetina nakanei Kimoto, 1969 are transferred to the genus Arthrotus Motschulsky, 1858. Lectotypes are designated for Dercetis taiwana Chûjô, 1938, and Antipha varipennis Jacoby, 1890. The synonymies of Antipha flavofasciata Baly, 1879 and Dercetes femoralis Weise, 1922 with Arthrotus flavocincta (Hope, 1831), Antipha varipennis Jacoby, 1890 with Dercetina chinensis (Weise, 1889) are supported. A new species, Dercetina barclayi sp. n. which was confused with Dercetina flavocincta, is described from Myanmar.  相似文献   

20.
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