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1.
本文记述中国珠足甲螨属的一新种角珠足甲螨,珠足甲螨属和孔珠足甲螨属中国6个新纪录种:南方珠足甲螨、俄罗斯珠足甲螨,疣珠足甲螨,塞氏珠足甲螨,棒珠足甲螨和刺孔珠足甲螨,并对上部分种类作了补充描述。  相似文献   

2.
陈浒  金道超  张燕 《应用生态学报》2018,29(5):1667-1676
为比较石漠化环境与喀斯特森林土壤螨类的群落结构差异,对贵州喀斯特地区朝营小流域栓皮栎林的土壤螨类群落结构本底进行了研究,经2014年各季节的4次调查,共发现土壤螨类3目54科83属.对螨类属数、个体数量、个体密度、Shannon多样性指数(H)、Margalef丰富度指数(SR)、Pielou均匀性指数(J)、捕食性螨类成熟度指数(MI)、甲螨MGP类群和甲螨营养结构等进行了分析.结果表明:土壤螨类在类群属数和个体数量上均以甲螨亚目的属占优势,夏季和秋季具有丰富的属数、较高的个体密度与多样性,春季和秋季具有丰富的个体数量,群落分布具有明显的表聚性.捕食性螨类夏季生态类群以K选择型为主,其他季节以r选择型为主;甲螨生态类群主要为P型和O型,缝甲螨属、异珠足甲螨属和合若甲螨属等属构成了栓皮栎林土壤螨类的营养功能集团.研究表明,该区山毛榉林与其他地区山毛榉林、其他不同类型森林的土壤螨类主要类群存在差异,其中含丰富属组成的派伦螨科、厉螨科、奥甲螨科和单翼甲螨科以及多奥甲螨属、派伦满属、菌甲螨属和单翼甲螨属等数量上占优势的类群属可作为山毛榉林土壤环境的生物指示.  相似文献   

3.
洼甲螨科的分类研究进展(蜱螨亚纲:甲螨目:懒甲螨总科)   总被引:1,自引:0,他引:1  
洼甲螨科隶属于蜱螨亚纲甲螨目懒甲螨总科,是低等甲螨中进化相对较高级,介于低等甲螨和高等甲螨之间的过渡类群,广泛分布于世界各大动物地理区,目前全世界有3属5亚属79种5亚种,国内现知2属16种.综述了洼甲螨科该科的分类沿革及分类研究进展;概述了洼甲螨科各属(亚属)的地理分布,指出该科目前所知分布较多的是古北界、新北界、东洋界;对中国洼甲螨科已知种进行了区系总结,目前青藏区和蒙新区各仅知1种,主要原因是缺乏深入研究;编制了洼甲螨科3个属及5个亚属和中国已知2属16种的分类检索表.  相似文献   

4.
本文描述宁夏海源县山地灰仓鼠小肠寄生的一种裸头科绦虫新种,命名为仓鼠萨氏无摄腺绦虫Aprostatandrya(Sudarikovina)cricetuli sp.n.。用其孕节感染当地的地螨,结果阐明了本新种绦虫的发育史及其中间宿主是当地的长毛腹翼甲螨(Galumna iongipluma)和超肋甲螨(Scheloribateschauhani)。  相似文献   

5.
【目的】为了解施秉喀斯特地区林地土壤甲螨的分布和群落组成特点,明确中国西南喀斯特地区林地类型对土壤甲螨群落密度、组成和物种多样性的影响,对该区林地土壤甲螨的群落结构及多样性进行了的调查和分析。【方法】2012年8月选取了中国西南施秉喀斯特地区典型生境中的8个样地,每个样地9个取样点,用Berlese-Tullgren装置分离土样24 h。多样性分析采用常见的多样性指数;群落相似性分析采用Jaccard相似性系数(CJ);群落聚类分析分别采用Marczewski Steinhaus 距离(Cms)和Bray-Curtis距离,应用R 2.11程序进行类平均法聚类。【结果】结果显示,中国西南喀斯特8个样地中土壤甲螨由少数的优势属和数量众多的稀有属组成。其中全菌甲螨属 Perscheloribates (22.48%)和长单翼甲螨属 Protoribates (11.45%)个体数量最为丰富。长单翼甲螨属 Protoribate、上罗甲螨属Epilohmannia、小奥甲螨属 Oppiella、小盾珠甲螨属 Suctobelbella 和盖头甲螨属 Tectocepheus 分布广泛。本区的甲螨组成(属级水平)表现出明显热带和亚热带地区特点。在天然常绿落叶阔叶林中,甲螨的个体数量和种类数较多,但多样性不高,而在人工针叶林中甲螨多样性最高。甲螨群落组成和分布特征多样,异质性高,特别是在天然常绿落叶阔叶林中突出。【结论】研究表明,施秉喀斯特生态系统的不同林分影响甲螨的物种多样性和群落稳定性,天然常绿落叶阔叶混交林是甲螨的“避难所”。  相似文献   

6.
贵州梵净山自然保护区土壤甲螨群落的季节动态   总被引:1,自引:0,他引:1  
2001年7月至2002年4月在不同的季节,对梵净山自然保护区属级水平上土壤甲螨结构的季节变化进行了调查.结果显示,土壤甲螨多度的四季变化为春季>冬季>秋季>夏季.土壤甲螨多样性的四季变化为秋季>夏季>冬季>春季.不同的季节土壤甲螨群落组成不同,但小奥甲螨属、小盾珠甲螨属、木单翼甲螨属3个属在每个季节均为绝对优势属.土壤甲螨主要分布在表层,但从夏季到冬季,土壤甲螨从表层向深层迁徙.  相似文献   

7.
报道西藏甲螨4新种和6新纪录种,标本采于西藏东南色季拉山,海拔3640-4800m,新种为:粒小隅甲螨Microtegeus granulatus Wang et Shen,sp.nov.,西藏真翅背甲螨Eupterotegaeus xizangensis Wang et Solhoy,sp.nov.,头新裸甲螨Neogymnobates capitatus Wang et Solhoy,sp.nov.,山溯甲螨Birsteinius monticolus Wang et Shen,sp.nov.,新纪录种为:纽氏平懒甲螨 Platynothrus nomatai Aoki,塞氏矮汉甲螨Nanhermannia sellnicki Forsslund,杜氏小赫甲螨Hermanniella dubinini Sitnikova,多齿刀肋甲螨Cultroribula dentata Willmann,曲波甲螨Unduloribates undulatus(Berlese),毛暗色甲螨Fuscozetes setosus(C.L.koch)。本文报道的波甲螨属,溯甲螨属,新裸甲螨属和暗色甲螨属为中国首次发现。  相似文献   

8.
本文记述中国珠足甲螨属BelbaVonHeyden的一新种角珠足甲螨B.cornutasp.nov,珠足甲螨属和孔珠足甲螨属中国6个新纪录种:南方珠足甲螨B.asakawaiEnami、俄罗斯珠足甲螨B.Bulanova-Zachvatkina,疣珠足甲螨B.verrucosaB.-Z.,塞氏珠足甲螨B.sellnickiB.-Z.,棒珠足甲螨B.corynopus(Hermann)和刺孔珠足甲螨Porobelbaspinosa(Sellnick),并对上述部分种类作了补充描述。  相似文献   

9.
1982—1983年,我们在浙江省天目山和重庆北碚采得一批甲螨,经鉴定其中一种属洛甲螨科Lohmanniidae,混居甲螨属Mixacarus;另两种属菌板鳃甲螨科Mycobatidae,点肋甲螨属Punctoribates。前一种为新种,定名为天目混居甲螨Mixacarus tianmuensis;后两种为中国新纪录。记述如下:  相似文献   

10.
鹤伴山国家森林公园土壤甲螨群落结构   总被引:3,自引:0,他引:3  
许士国  付荣恕 《生态学报》2010,30(23):6654-6660
2001年5月、8月、11月对鹤伴山国家森林公园土壤甲螨群落结构进行定量研究,结果表明:该地区土壤甲螨群落由41属组成,其中优势属及亚优势属5个:木单翼甲螨、合若甲螨及菌甲螨、小奥甲螨、礼服甲螨。各样点土壤甲螨群落的组成和数量分布均有明显不同,样点Ⅰ有31属,样点Ⅱ23属;密度最高的样点Ⅲ达8450头/m2,为平均密度的1.3倍,样点Ⅳ密度最低,虫口密度仅有4583头/m2,为平均密度的0.7倍。甲螨群落数量的季节变化明显,春季数量最高,秋季次之,夏季最低。MGP分析结果表明,该区土壤甲螨群落属于O型和P型,P群的种类和数量均明显多于M群和G群。甲螨群落的异质性高,多样性指数较高,可达最大多样性指数的4/5,各样点之间的多样性指数有一定的差异。各样点之间的群落相似性较高,少数样点之间为中等不相似,大多数样点间为中度相似,两种聚类方法结果明显不同,说明植被类型及海拔高度对土壤甲螨群落种类组成具有一定的影响,对其数量分布的影响更加明显。  相似文献   

11.
For the rational design of a stable collagen triple helix according to the conventional rule that the pyrrolidine puckerings of Pro, 4-hydroxyproline (Hyp) and 4-fluoroproline (fPro) should be down at the X-position and up at the Y-position in the X-Y-Gly repeated sequence for enhancing the triple helix propensities of collagen model peptides, a series of peptides were prepared in which X- and Y-positions were altogether occupied by Hyp(R), Hyp(S), fPro(R) or fPro(S). Contrary to our presumption that inducing the X-Y residues to adopt a down-up conformation would result in an increase in the thermal stability of peptides, the triple helices of (Hyp(S)-Hyp(R)-Gly)(10) and (fPro(S)-fPro(R)-Gly)(10) were less stable than those of (Pro-Hyp(R)-Gly)(10) and (Pro-fPro(R)-Gly)(10), respectively. As reported by B?chinger's and Zagari's groups, (Hyp(R)-Hyp(R)-Gly)(10) which could have an up-up conformation unfavorable for the triple helix, formed a triple helix that has a high thermal stability close to that of (Pro-Hyp(R)-Gly)(10). These results clearly show that the empirical rule based on the conformational preference of pyrrolidine ring at each of X and Y residues should not be regarded as still valid, at least for predicting the stability of collagen models in which both X and Y residues have electronegative groups at the 4-position.  相似文献   

12.
Xia Z  Zhuang J 《Luminescence》2012,27(5):379-381
A novel blue‐emitting Sr3.5Y6.5O2(PO4)1.5(SiO4)4.5:Eu2+ phosphor was synthesized via a solid‐state reaction. Powder X‐ray diffraction (XRD) analysis demonstrated that the Sr3.5Y6.5O2(PO4)1.5(SiO4)4.5 host had a hexagonal crystal structure in the space group P63/m and unit cell parameters a = 9.418 Å, c = 6.900 Å. The as‐prepared phosphor showed a blue emission and all the main emission peaks were located at around 466 nm for different excitation wavelengths of 297, 333 and 391 nm. The temperature dependence of the photoluminescence property was investigated in the range 20–250 °C, and the emission intensity decreased to 71% of the initial value at room temperature on increasing the temperature to 150 °C. According to the classical theory of fluorescent thermal quenching, the activation energy (ΔE) for the thermal quenching luminescence of the as‐prepared Sr3.45Y6.5O2(PO4)1.5(SiO4)4.5:0.05Eu2+ phosphor was determined to be 0.20 eV. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

13.
The enzymes chlorocatechol-1,2-dioxygenase, chloromuconate cycloisomerase, dienelactone hydrolase, and maleylacetate reductase allow Ralstonia eutropha JMP134(pJP4) to degrade chlorocatechols formed during growth in 2,4-dichlorophenoxyacetate or 3-chlorobenzoate (3-CB). There are two gene modules located in plasmid pJP4, tfdC(I)D(I)E(I)F(I) (module I) and tfdD(II)C(II)E(II)F(II) (module II), putatively encoding these enzymes. To assess the role of both tfd modules in the degradation of chloroaromatics, each module was cloned into the medium-copy-number plasmid vector pBBR1MCS-2 under the control of the tfdR regulatory gene. These constructs were introduced into R. eutropha JMP222 (a JMP134 derivative lacking pJP4) and Pseudomonas putida KT2442, two strains able to transform 3-CB into chlorocatechols. Specific activities in cell extracts of chlorocatechol-1,2-dioxygenase (tfdC), chloromuconate cycloisomerase (tfdD), and dienelactone hydrolase (tfdE) were 2 to 50 times higher for microorganisms containing module I compared to those containing module II. In contrast, a significantly (50-fold) higher activity of maleylacetate reductase (tfdF) was observed in cell extracts of microorganisms containing module II compared to module I. The R. eutropha JMP222 derivative containing tfdR-tfdC(I)D(I)E(I)F(I) grew four times faster in liquid cultures with 3-CB as a sole carbon and energy source than in cultures containing tfdR-tfdD(II)C(II)E(II)F(II). In the case of P. putida KT2442, only the derivative containing module I was able to grow in liquid cultures of 3-CB. These results indicate that efficient degradation of 3-CB by R. eutropha JMP134(pJP4) requires the two tfd modules such that TfdCDE is likely supplied primarily by module I, while TfdF is likely supplied by module II.  相似文献   

14.
Sim GE  Goh CJ  Loh CS 《Plant cell reports》2008,27(8):1281-1289
We analysed the endogenous cytokinin levels of Dendrobium Madame Thong-In seedlings grown in vitro during vegetative and flowering-inductive periods. HPLC was used to fractionate the extracts and radioimmunoassay (RIA) was used for assay of zeatin (Z), dihydrozeatin (DZ), N(6)-(Delta(2)-isopentenyl)-adenine (iP) and their derivatives. Coconut water used in experiments was found to contain high level (>136 pmol ml(-1)) of zeatin riboside (ZR). Protocorms and seedlings cultured in medium with coconut water were found to contain 0.5-3.9 pmol g(-1) FW of the cytokinins analysed. Seedlings (1.0-1.5 cm) cultured in flowering-inductive liquid medium containing 6-benzyladenine (BA, 4.4 muM) and coconut water (CW, 15%) contained up to 200 and 133 pmol g(-1) FW of iP and iPA, respectively. These levels were significantly higher than all other cytokinins analysed in seedlings of the same stage and were about 80- to 150-folds higher than seedlings cultured in non-inductive medium. During the transitional (vegetative to reproductive) stage, the endogenous levels of iP (178 pmol g(-1) FW) and iPA (63 pmol g(-1) FW) were also significantly higher than cytokinins in the zeatine (Z) and dihydrozeatin (DZ) families in the same seedlings. Seedlings that grew on inductive medium but remained vegetative contained lower levels of iPA. The importance of the profiles of iP and its derivatives in induction of in vitro flowering of D. Madame Thong-In is discussed.  相似文献   

15.
The biology of the fruit fly Bactrocera tau, an important horticultural pest, was studied under laboratory conditions at 25°C and 60–70% relative humidity on Cucurbita maxima. The duration of mating averaged 408.03 ± 235.93 min. After mating, the female fly had a preoviposition period of 11.7 ± 4.49 days. The oviposition rate was 9.9 ± 8.50 eggs and fecundity was 464.6 ± 67.98 eggs/female. Eggs were elliptical, smooth and shiny white, turning darker as hatching approached, and measured 1.30 ± 0.07 mm × 0.24 ± 0.04 mm. The chorion has polygonal microsculpturing and is species-specific with polygonal walls. The egg period lasts for 1.3 ± 0.41 days. The duration of the larval period is 1.2 ± 0.42, 1.7 ± 0.48 and 4.0 ± 0.94 days for first, second and third instars, respectively. Pupation occurs in the sand or soil and pupal periods are 7.0 ± 0.47 days. The life cycle from egg to adult was completed in 14.2 ± 1.69 days; the longevity of mated females and males was 130.33 ± 14.18 and 104.66 ± 31.21 days, respectively. At least two to three generations were observed from June 2008 to June 2009.  相似文献   

16.
17.
R M Wartell 《Biopolymers》1972,11(4):745-759
Helix–coil transition curves are calculated for poly (dA) poly(dT) and poly (dA-dT) poly (dA-dT) using the integral equation approach of Goel and Montroll.5 The transitions are described by the loop entropy model with the exponent of the loop entropy factor, k, remaining an arbitrary constant. The theoretical calculations are compared with experimental transition curves of the two polymers. Results indicate that the stacking energies for these two polymers differ by about 1 kcal/mole of base pairs. Also, a fit between theory and experiment was not possible for k > 1.70.  相似文献   

18.
This article reports on the optical properties of Er3+ ions doped CdO–Bi2O3–B2O3 (CdBiB) glasses. The materials were characterized by optical absorption and emission spectra. By using Judd–Ofelt theory, the intensity parameters Ωλ (λ = 2, 4, 6) and also oscillatory strengths were calculated from the absorption spectra. The results were used to compute the radiative properties of Er3+:CdBiB glasses. The concentration quenching and energy transfer from Yb3+–Er3+ were explained. The stimulated emission cross‐section, full width at half maximum (FWHM) and FWHM × values are also calculated for all the Er3+:CdBiB glasses. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

19.
Synthesis and single crystal X-ray structures of the first paramagnetic transition metal complexes containing chiral ethylenedithio-tetrathiafulvalene-oxazoline (EDT-TTF-OX) 1a-c and ethylenedithio-tetrathiafulvalene-thiomethyloxazoline 2 (EDT-TTF-(SMe)OX) ligands based on copper (II) and cobalt (II) are described. The racemic [EDT-TTF-OX][Cu(hfac)2] complex 3a crystallizes in the triclinic centrosymmetric space group , whereas the enantiopure counterparts 3b-c crystallize in the triclinic non-centrosymmetric space group P1. Cu(II) adopts a distorted square pyramidal coordination geometry, a much weaker Cu?STTF interaction also being identified. The same coordination pattern around Cu(II) is observed in the complex [(rac)-EDT-TTF-(SMe)OX][Cu(hfac)2] (4) in spite of the bidentate nature of the redox active ligand. DFT theoretical calculations afforded two equilibrium configurations for a corresponding model complex, in which the metal centre establishes secondary coordination either with one STTF or with the SMe group. The same ligand coordinates the cobalt (II) to afford the octahedral complex [(rac)-EDT-TTF-(SMe)OX][Co(hfac)2] (5). In all these novel complexes, the paramagnetic centres are structurally and magnetically isolated. Cyclic voltammetry measurements show the stability of the radical cation species.  相似文献   

20.
The formation of cationic palladium(II)complexes [TrpyPdII]+X by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X and the solvent. The mononuclear cations, which are only formed with X = BArF, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of PdII. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPdIIL]+ with L = CH3NC, tBuNH2, PMe3, PEt3 and PiPr3 and [TrpyPdIIL2]+ with L = PMe3 were prepared from the mononuclear cations [TrpyPdII]+BArF−. From structural studies it becomes apparent, that the formation of stable five coordinate PdII species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPdII unit.  相似文献   

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