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1.
Studies of Al partitioning and accumulation and of the effect of Al on the growth of intact wheat (Triticum aestivum L.) roots of cultivars that show differential Al sensitivity were conducted. The effects of various Al concentrations on root growth and Al accumulation in the tissue were followed for 24 h. At low external Al concentrations, Al accumulation in the root tips was low and root growth was either unaffected or stimulated. Calculations based on regression analysis of growth and Al accumulation in the root tips predicted that 50% root growth inhibition in the Al-tolerant cv Atlas 66 would be attained when the Al concentrations were 105 [mu]M in the nutrient solution and 376.7 [mu]g Al g-1 dry weight in the tissue. In contrast, in the Al-sensitive cv Tam 105, 50% root growth inhibition would be attained when the Al concentrations were 11 [mu]M in the nutrient solution and 546.2 [mu]g Al g-1 dry weight in the tissue. The data support the hypotheses that differential Al sensitivity correlates with differential Al accumulation in the growing root tissue, and that mechanisms of Al tolerance may be based on strategies to exclude Al from the root meristems.  相似文献   

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Peixoto de Azevedo is located in the north of State of Mato Grosso, where environmental alterations led to an outbreak of American cutaneous leishmaniasis in the 80s. The parasite from patients was characterized as Leishmania (V.) braziliensis. The aim of this study is to contribute to the sand fly ecology of Central-West Brazil. Captures were carried out monthly using CDC light traps. Twenty-six species of sand fly were characterized; among which Lutzomyia (Lutzomyia) spathotrichia, L. runoides and L. (Psychodopygus) llanosmartinsi were recorded in the State of Mato Grosso for the first time. L. (Nyssomyia) whitmani, L. (N.) antunesi, L. (L.) spathotrichia, L. (P.) c. carrerai, L. (P.) complexa, L. (P.) lainsoni and L. (N.) umbratilis constituted 92.4% of the local fauna, among which L. (N.) whitmani and L. (N.) antunesi, accounting for about 53% of the fauna at the stations of capture. On the vertical distribution of sand flies on the Beira-Rio Farm, L. (N.) whitmani and L. (N.) antunesi prevailed at ground level and in the canopy, respectively, whereas on the BR-080, L. (P.) llanosmartinsi was prevalent on the ground and L. (P.) c. carrerai, in the canopy. It is suggested that L. (N.) umbratilis is the local vector.  相似文献   

4.
Rice (Oryza sativa L.) shows the highest tolerance to Al toxicity among small-grain cereal crops, however, the mechanisms and genetics responsible for its high Al tolerance are not yet well understood. We investigated the response of rice to Al stress using the japonica variety Koshihikari in comparison to the indica variety Kasalath. Koshihikari showed higher tolerance at various Al concentrations than Kasalath. The Al content in root apexes was less in Koshihikari than in Kasalath, suggesting that exclusion mechanisms rather than internal detoxification are acting in Koshihikari. Al-induced secretion of citrate was observed in both Koshihikari and Kasalath, however, it is unlikely to be the mechanism for Al tolerance because there was no significant difference in the amount of citrate secreted between Koshihikari and Kasalath. Quantitative trait loci (QTLs) for Al tolerance were mapped in a population of 183 backcross inbred lines (BILs) derived from a cross of Koshihikari and Kasalath. Three putative QTLs controlling Al tolerance were detected on chromosomes 1, 2 and 6. Kasalath QTL alleles on chromosome 1 and 2 reduced Al tolerance but increased tolerance on chromosome 6. The three QTLs explained about 27% of the phenotypic variation in Al tolerance. The existence of QTLs for Al tolerance was confirmed in substitution lines for corresponding chromosomal segments.  相似文献   

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An internal detoxification mechanism for Al was investigated in an Al-accumulating plant, hydrangea (Hydrangea macrophylla), focusing on Al forms present in the cells. The leaves of hydrangea contained as much as 15.7 mmol Al kg-1 fresh weight, and more than two-thirds of the Al was found in the cell sap. Using 27Al- nuclear magnetic resonance, the dominant peak of Al was observed at a chemical shift of 11 to 12 parts per million in both intact leaves and the extracted cell sap, which is in good accordance with the chemical shift for the 1:1 Al-citrate complex. Purification of cell sap by molecular sieve chromatography (Sephadex G-10) combined with ion-exclusion chromatography indicated that Al in fractions with the same retention time as citric acid contributed to the observed 27Al peak in the intact leaves. The molar ratio of Al to citric acid in the crude and purified cell sap approximated 1. The structure of the ligand chelated with Al was identified to be citric acid. Bioassay experiments showed that the purified Al complex from the cell sap did not inhibit root elongation of corn (Zea mays L.) and the viability of cells on the root tip surface was also not affected. These observations indicate that Al is bound to citric acid in the cells of hydrangea leaves.  相似文献   

7.
对丽盲蝽属 (丽盲蝽亚属 )Lygocoris (subg .Lygocoris)的中国种类作了修订。文中共包括 19个种 ,其中有 12新种 ,1个中国新纪录种 ,并包括 1项新等级的认定。即暗胝丽盲蝽L .(L .)calligersp .nov .(正模 :四川峨眉山九老洞 ) ,程氏丽盲蝽L .(L .)chengisp .nov .(正模 :四川峨眉山大乘寺 ) ,晕斑丽盲蝽L .(L .)diffusomaculatussp .nov .(正模 :甘肃榆中兴隆山 ) ,淡色丽盲蝽L .(L .)dilutussp .nov .(正模 :甘肃夏河县合作 ) ,锈褐丽盲蝽L .(L .) ferrugineussp .nov .(正模 :云南哀牢山 ) ,褐盾丽盲蝽L .(L .) fuscoscutel latus (Reuter ,190 6 )stat .nov .[由L .(L .)striicornisvar.fuscoscutellatus升为种级阶元 ],广西丽盲蝽L .(L .) guangxiensissp .nov .(正模 :广西龙胜 ) ,东亚丽盲蝽L .(L .)idoneus(Linnavuori,196 3) (中国新纪录种 ) ,完脊丽盲蝽L .(L .)integricarinatussp .nov .(甘肃榆中麻家寺 ) ,林氏丽盲蝽L .(L .)linnavuoriisp .nov .(云南哀牢山簸箕坝 ) ,长翅丽盲蝽L .(L .)longipennis (Reuter ,190 6 ) ,斑盾丽盲蝽L .(L .)maculis cutellatussp .nov .(四川理县刷经寺 ) ,原丽盲蝽L .(L .) pabulinus (Linnaeus ,176 1) ,红盾丽盲蝽L .(L .)rufiscutellatussp .nov .(甘  相似文献   

8.
The morphological characters used to differentiate species in the genus Labiostrongylus Yorke & Maplestone, 1926, parasitic in macropodid and potoroid marsupials, are discussed. The genus is divided into three subgenera Labiostrongylus (Labiostrongylus), L. (Labiomultiplex) n. subg. and L. (Labiosimplex) n. subg. on the basis of the presence or absence of interlabia and the morphology of the oesophagus. A key to the subgenera is given and a detailed revision of two of the subgenera is presented. Keys to each of the subgenera are given, the species discussed being: L. (L.) labiostrongylus) (type-species) (syn. L. (L.) insularis, L. (L.) grandis, L. (L.) macropodis sp. inq. and L. (L.) nabarlekensis n. sp., in the subgenus Labiostrongylus, and L. (Lm.) eugenii, L. (Lm.) novaeguineae, L. (Lm.) onychogale, L. (Lm.) uncinatus, L. (Lm.) billardierii n. sp., L. (Lm.) constrictis n. sp., L. (Lm.) kimberleyensis n. sp., L. (Lm.) thylogale n. sp., and L. (Lm.) potoroi, n. sp., in the subgenus Labiomultiplex.  相似文献   

9.
The volatile constituents of the essential oils of 23 taxa belonging to the Apioideae subfamily were studied in detail. The investigated taxa were Pimpinella serbica (Vis.) Bentham & Hooker, Libanotis montana Cr., Cnidium silaifolium (Jacq.) Simk. ssp. orientale (Boiss.) Tutin, Bupleurum praealtum L., B. sibthorpianum S. S. var. diversifolium (Roch.) Hay, Aegopodium podagraria L., Torilis anthriscus (L.) Gmel., Orlaya grandiflora (L.) Hoffm., Laserpitium siler L., Laser trilobum (L.) Brokh., Chaerophyllum aureum L., C. hirsutum L., C. temulum L., Pastinaca sativa L., P. hirsuta Pancic., Tordylium maximum L., Physospermum cornubiense (L.) DC., Peucedanum alsaticum L., P. oreoselinum (L.) Moench, P. cervaria (L.) Cuss., P. austriacum (Jacq.) Koch, P. longifolium W. et K., and P. officinale L. All of these species grow wild in the central part of the Balkan Peninsula. The essential oils were found to be complex mixtures of various compounds, more than 100 constituents being in each taxon, with contributions of main products never exceeding 25% of the total content. Sesquiterpene hydrocarbons were found to be the main group of constituents of all taxa, except for Peucedanum species, where monoterpene hydrocarbons were identified as the main components. The chemotaxonomic value of the essential-oil composition is discussed according to results of principal-component analysis (PCA). The essential-oil composition mainly reflects current taxonomic relationships between the investigated taxa.  相似文献   

10.
Leioproctus (Anacolletes) is revised to contain only L. (A.) bimaculatus (Smith). A new subgenus, Leioproctus (Odontocolletes) , is erected. Four new species ( Leioproctus (Odontocolletes) asper, L. (O.) cardaleae, L. (O.) erythropyga and L. (O.) xanthozoster) are described and L. callurus (Cockerell), L. nomiaeformis (Cockerell), L. pachyodontus (Cockerell) and L. rudissimus (Cockerell) are transferred.  相似文献   

11.
10种菊科植物水提液对小麦幼苗生长的影响   总被引:21,自引:8,他引:13  
用小白酒草、黄鼠草、刺儿菜、一年蓬、苍耳、苦苣菜、旋覆花、紫菀、黄花蒿、野塘蒿等10种菊科植物的水提液,对小麦进行不同浓度的皿内沙培实验,分别对小麦的根长、苗高及鲜重等三项指标进行测定的统计结果表明:10种菊科植物水提液对小麦幼苗生长的影响依种类有差异,其中旋覆花、黄花蒿、野塘蒿、紫菀对小麦表现出明显克生作用,而小白酒草、黄鼠草则表现出一定的促生作用;刺耳菜、一年蓬、苍耳对小麦幼苗生长的影响不明显。  相似文献   

12.
Allozyme electrophoresis was used to compare specimens of Labiostrongylus (Labiosimplex) bancrofti from two species of Australian macropodids, Macropus dorsalis and M. parryi, with a related species, L. (Labiomultiplex) uncinatus which also infests M. dorsalis. Each nematode was characterised genetically at 18 enzyme loci. The level of fixed genetic differences detected between L. (Ls.) bancrofti from M. parryi and M. dorsalis (83%) is equivalent to that when each is compared to the morphologically distinct species L. (Lm.) uncinatus (89–94%), demonstrating unequivocally that the taxon L. (Ls.) bancrofti represents at least two species, one in M. parryi and one in M. dorsalis. In addition, morphological evidence from additional specimens collected from M. parryi suggested the existence of a third sibling species in this group. All three species differ in the shape of the spicule tips; L. (Ls.) bancrofti has longer spicules than either of the two new species. L. (Ls.) quasibancrofti n. sp. has smaller cephalic papillae, larger oesophago-intestinal diverticula, a larger genital cone and a longer female tail than L. (Ls.) turnbulli n. sp. The taxon L. (Ls.) bancrofti consists, therefore, of three species, L. (Ls.) turnbulli in M. parryi, L. (Ls.) quasibancrofti in M. dorsalis, and L. (Ls.) bancrofti found in both host species, as well as in four species of rock wallabies.  相似文献   

13.
Previous studies provided evidence that the role of TNF in the control of Leishmania (Leishmania) major might vary with the parasite strain. Here, we analyzed the development and outcome of cutaneous leishmaniasis in C57BL/6 wild-type (B6.WT) and TNF-deficient (B6. TNF(-/-)) mice infected with two different isolates of L. (L.) major (FRIEDLIN vs. BNI). L. (L.) major BNI caused progressive, fatal disease in B6.TNF(-/-) mice. In contrast, B6.TNF(-/-) mice infected with the L. (L.) major FRIEDLIN strain exhibited partial resistance characterized by chronic, non-healing skin lesions without lethality. Analysis of the tissue parasite numbers showed that the numbers of L. (L.) major FRIEDLIN and BNI parasites were comparable in footpads and lymph nodes of B6.TNF(-/-) mice, whereas in the spleen the parasite numbers were strikingly lower in the case of L. (L.) major FRIEDLIN. In vitro, cytokine-activated inflammatory macrophages killed L. (L.) major FRIEDLIN more efficiently than L. (L.) major BNI. These results suggest that in the absence of TNF, the course of leishmaniasis depends on the biology of the inoculated L. (L.) major strain, which most likely explains the previously published discrepant results on the role of TNF in leishmaniasis.  相似文献   

14.
The relationship between Al-induced depolarization of root-cell transmembrane electrical potentials (Em) and Al tolerance in wheat (Triticum aestivum L.) was investigated. Al exposure induced depolarizations of Em in the Al-tolerant wheat cultivars Atlas and ET3, but not in the Al-sensitive wheat cultivars Scout and ES3. The depolarizations of Em occured in root cap cells and as far back as 10 mm from the root tip. The depolarization was specific to Al3+; no depolarization was observed when roots were exposed to the rhizotoxic trivalent cation La3+. The Al-induced depolarization occurred in the presence of anion-channel antagonists that blocked the release of malate, indicating that the depolarization is not due to the electrogenic efflux of malate2-. K+-induced depolarizations in the root cap were of the same magnitude as Al-induced depolarizations, but did not trigger malate release, indicating that Al-induced depolarization of root cap cell membrane potentials is probably linked to, but is not sufficient to trigger, malate release.  相似文献   

15.
The incidence of HIV/Leishmania co-infection decreases after antiretroviral drug therapy; therefore, the in vitro and in vivo activity of three antiretroviral drugs against Leishmania (Viannia) braziliensis and L. (L.) amazonensis was evaluated. Different concentrations of indinavir (IDV), atazanavir (ATV), and ritonavir (RTV) were added to promastigote cultures, and the 50% inhibitory concentration (IC50) was determined. IDV and RTV were also evaluated against intracellular amastigotes, and the Infection Index determined. BALB/c mice, infected with L. (L.) amazonensis in the left footpad, were treated orally with IDV and RTV for 30days, and monitored by measuring the footpad thickness and parasite load of regional lymph nodes and spleen. For promastigotes, IDV exhibited an IC50 value of 100μM against L.(L.) amazonensis. The RTV IC50 for L. (L.) amazonensis and L. (V.) braziliensis were 40 and 2.3μM, respectively, and the ATV IC50 for L. (V.) braziliensis was 266μM. For intracellular amastigotes, IDV (25, 50, and 100μM) significantly decreased the Infection Index of L. (L.) amazonensis (56.8%, 47.9%, and 65.0%) and L. (V.) braziliensis (37.8%, 48.7%, and 43.2%). RTV (12.5, 25, and 50μM) decreased the infection index of L. (L.) amazonensis by 26.3%, 42.4%, and 44.0%, and that of L. (V.) braziliensis by 27.6%, 37.3%, and 39.2%. Antiretroviral-treated mice had a significant reduction in footpad thickness after the third week of IDV and after the fifth week of RTV treatment. However, there was no reduction in parasite load. These results suggest that IDV and RTV have anti-Leishmania activity, but only in higher concentrations.  相似文献   

16.
During an excursion in the Landschaftspark Duisburg-Nord in 2009 and 2010 we were able to collect and identify more than 100 specimens of microfungi on different parts of cultivated and wild plant species. We found parasitic and saprophytic microfungi on trees, bushes and herbaceous plants. Some of them have been observed only rarely until now. Most of the collected microfungi species belong to the classes of Ascomycetes, Basidiomycetes and Deuteromycetes - for example Leptosphaeria modesta (Desm.) Rabenh. on Knautia cf. arvensis (L.) Coult., Ramularia urticae Ces. on Urtica dioica L., Stigmina glomerulosa (Sacc.) S. Hughes on Juniperus communis L., Pseudomassaria corni (Sowerby) Arx on Cornus alba L., Mollisia discolor (Mont.) W. Phillips on Cornus alba L., Botryosphaeria quercuum (Schwein.) Sacc. on Quercus robur L., Peronospora cytisi Rostr. on Laburnum anagyroides Med., Microsphaera guarinonii Briosi and Cavara on Laburnum anagyroides Med., Brachysporium dingleyae S. Hughes on Fraxinus angustifolia Vahl and Rhododendron spec., Mamiania fimbriata (Pers.) Ces. and De Not. on Carpinus betulus L., Atopospora betulina (Fr.) Petr. on Betula pendula Roth, Septoria robiniae (Lib.) Desm. (=Phloeospora robiniae (Lib.) H?hn.) on Robinia pseudoacacia L., Chalara hughesii Nag Raj and W.B. Kendr. on Quercus robur L.. All specimens are located in the Herbarium ESS, Mycotheca Parva collection G.B. Feige and N. Ale-Agha.  相似文献   

17.
The pattern and kinetics of internal dissemination and frequency of cutaneous metastatic lesions resulting from experimental infection of golden hamsters with Leishmania (Viannia) panamensis and Leishmania (Viannia) guyanensis were examined. Nineteen strains were evaluated: 16 L. (V.) panamensis isolated from patients and 3 L. (V.) guyanensis, 2 isolated from human cases and 1 WHO reference strain originating from a sandfly vector. Lymphatic dissemination occurred within 3 mo and was observed for 16 of 16 (100%) of L. (V.) panamensis and 3 of 3 (100%) of L. (V.) guyanensis. Parasites were cultured infrequently from liver and spleen: 3 of 125 (2%) L. (V.) panamensis and 1 of 22 (5%) L. (V.) guyanensis. Decreased frequency of isolation from the inoculation site and draining lymph nodes over time was accompanied by increased frequency of isolation from distant lymph nodes. Dilution of triturated tissue samples resulted in an increased efficiency of parasite culture. Both primary lesions and secondary cutaneous metastatic lesions were more severe in hamsters infected with L. (V.) guyanensis than with L. (V.) panamensis. Cutaneous metastatic lesions were produced more frequently by L. (V.) guyanensis, 24 of 46 hamsters (52%), than by L. (V.) panamensis, 28 of 252 hamsters (11%). Individual Leishmania strains displayed distinctive propensities to produce cutaneous metastases, manifested as a reproducible phenotype. Metastatic pathogenicity was independent of the inoculum dose, supporting the dissociation of infectivity and pathogenicity.  相似文献   

18.
紫苏、白苏的抑菌实验   总被引:14,自引:2,他引:12  
用不同溶剂浸泡或处理紫苏后,进行抑菌实验,结果表明:10%以上浓度的紫苏水浸液,12.5%水煎液和乙醇提取液对白色念球菌、新型隐球菌以及红色毛癣菌、石膏样小孢子癣菌、絮状表皮癣菌有较好的抑菌效果。紫苏、皱紫共、白苏对真菌均有抑菌作用,但皱紫苏对绿脓杆菌、白苏对克柔氏念球菌、白色念球菌以及绿脓杆菌效果更为明显。  相似文献   

19.
The grasses are the most important plant family for food production. Despite the domestication of Oryza sativa L. (rice), Triticum aestivum L. (wheat), Zea mays L. (corn), Hordeum vulgare L.(barely), Secale cereale L. (rye), Avena sativa L. (oats), Sorghum bicolor (L.) Moench (sorghum), Saacharum officinarum L. (sugar cane), Pennisetum glaucum (L.) R. Br. (pearl millet), Panicum virgatum L. (switchgrass), Eleusine coracana (L.) Gaertn (finger millet.) and Eragrostis tef (Zucc.) Trotter (tef), the family has not been widely studied biogeographically (Bouchenak-Khelladi et al.,2010). Other notable economic uses of grasses include landscaping, construction (primarily bamboos), and biofuel production (Miscanthus x giganteus J.M. Greef & Deuter ex Hodk. & Renvoize, Panicum L., and Zea L.).  相似文献   

20.
Background/Objectives: Parasites of the subgenus Leishmania (Viannia) cause varying clinical symptoms ranging from cutaneous leishmaniases (CL) with single or few lesions, disseminated CL (DL) with multiple lesions to disfiguring forms of mucocutaneous leishmaniasis (MCL). In this population genetics study, 37 strains of L. (V.) guyanensis, 63 of L. (V.) braziliensis, four of L. (V.) shawi, six of L. (V.) lainsoni, seven of L. (V.) naiffi, one each of L. (V.) utingensis and L. (V.) lindenbergi, and one L. (V.) lainsoni/L. naiffi hybrid from different endemic foci in Brazil were examined for variation at 15 hyper-variable microsatellite markers. Methodology/Principal findings: The multilocus microsatellite profiles obtained for the 120 strains were analysed using both model- and distance-based methods. Significant genetic diversity was observed for all L. (Viannia) strains studied. The two cluster analysis approaches identified two principal genetic groups or populations, one consisting of strains of L. (V.) guyanensis from the Amazon region and the other of strains of L. (V.) braziliensis isolated along the Atlantic coast of Brazil. A third group comprised a heterogeneous assembly of species, including other strains of L. braziliensis isolated from the north of Brazil, which were extremely polymorphic. The latter strains seemed to be more closely related to those of L. (V.) shawi, L. (V.) naiffi, and L. (V.) lainsoni, also isolated in northern Brazilian foci. The MLMT approach identified an epidemic clone consisting of 13 strains of L. braziliensis from Minas Gerais, but evidence for recombination was obtained for the populations of L. (V.) braziliensis from the Atlantic coast and for L. (V.) guyanensis. Conclusions/Significance: Different levels of recombination versus clonality seem to occur within the subgenus L. (Viannia). Though clearly departing from panmixia, sporadic, but long-term sustained recombination might explain the tremendous genetic diversity and limited population structure found for such L. (Viannia) strains.  相似文献   

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