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1.
为筛选牛尾菜抗氧化作用的药效活性物质,提升牛尾菜的药材质量控制标准,该研究测定了13批牛尾菜的高效液相指纹图谱,并进行相似度评价和聚类分析,采用偏最小二乘回归分析法将共有峰与抗氧化的抑制率进行关联性分析,并进行单体化合物抗氧化试验验证。结果表明:(1)该文建立了含有14个主要共有峰的13 批牛尾菜HPLC指纹图谱。(2)13批牛尾菜样品聚为两类。(3)指纹图谱中的1、2、3、5、6、9、14号峰面积与抗氧化效果呈正相关,4、7、8、10、11、12号峰与抗氧化效果呈负相关,其中9、11、3、4、5号峰的VIP值均大于1。(4)9号峰为齐墩果酸,10号峰为熊果酸,9 号峰对ABTS 自由基的清除能力最大。该研究认为牛尾菜抗氧化作用不是单一成分起作用,而是多种成分综合作用的结果,其中9号峰(齐墩果酸)可能是牛尾菜具有抗氧化作用的物质基础。  相似文献   

2.
We investigated the influence of native flora and fauna on the establishment and persistence of the exotic weed Ageratina riparia (Asteraceae) in disturbed and regenerating rainforests on the Springbrook plateau of south‐eastern Queensland. The height and ground cover of A. riparia was positively associated with light availability beneath the rainforest canopy and negatively associated with forest leaf litter biomass. Regenerating rainforest with the associated increases in litter and decrease in light availability could therefore inhibit the establishment and density of A. riparia. The red‐necked pademelon, Thylogale thetis, browsed extensively on A. riparia, but the pattern of browsing was not associated with light availability, forest leaf litter biomass or density of A. riparia. Browsing and incidental damage by T. thetis breaks up the broad stands of A. riparia. The physical damage caused by T. thetis, and the inhibition to establishment and density of A. riparia by native plant species, combine to reduce the environmental threat associated with A. riparia.  相似文献   

3.
Summary Two leptodactylid frog species Ranidella signifera and R. riparia occupy adjacent but different habitat types in the Flinders Ranges of South Australia. R. signifera is found in slow-flowing creeks with mud or sand substrates. R. riparia occupies fast-flowing rocky creeks. The two coexist in a narrow overlap zone with heterogeneous habitats. Laboratory experiments were used to test habitat preferences of tadpoles in a tub with sand and rock substrates. R. riparia was most commonly found on the rock substrate. R. signifera showed no distinct preference for sand, but when mixed with R. riparia increased its use of the habitat in the spaces between and under rocks. This was particularly apparent in flowing water where 81% of all R. signifera tadpoles were observed in this sheltered habitat.The data suggest that R. signifera tadpoles have reduced fitness in flowing water because they cannot exploit exposed feeding sites where most of the algae grow, and that interspecific interactions with R. riparia tadpoles reduce their fitness further. This helps to explain why R. signifera do not extend their distribution into R. riparia occupied creeks. The data do not explain why R. riparia do not colonize the slow muddy creeks occupied by R. signifera.  相似文献   

4.
We examined the influence of acarodomatia in the riverbank grape Vitis riparia Michaux (Vitaceae) on the distribution and abundance of predatory mites (Phytoseiidae) and their interactions with herbivorous mites. Acarodomatia are tufts of nonglandular trichomes or pits located in major leaf vein axes of many species of woody perennial plants and are often occupied by predatory and mycophagous mites. In common garden plantings of different accessions of V. riparia we found a significant positive relationship between size of domatia and the abundance of naturally occurring predatory mites. Behavior of adult predatory mites may explain this positive association, in part. In separate laboratory experiments, gravid females of Typhlodromus pyri Scheuten and Amblyseius andersoni Chant spent more time and deposited more eggs on half of a V. riparia leaf with accessible domatia versus the other half in which access to domatia was blocked with pruning tar. Domatia also had population consequences. In an outdoor experiment using potted grapevines, population size of T. pyri and A. andersoni mites was greater on V. riparia with open domatia compared to V. riparia in which domatia were blocked with pruning tar. Population size of predatory mites was also greater on V. riparia with domatia than on Vitis vinifera L., whether their axils were blocked or not. Since V. vinifera have very small domatia, these results indicate that the presence of domatia is important, not just access to vein axils. Elevated predatory mite populations in response to domatia, however, did not translate into differences in the abundance of European red mite Panonychus ulmi (Koch), an important pest of grapes.Overall, these results indicate that domatia in uncultivated V. riparia promote higher densities of some species of generalist phytoseiid mites. However, domatia are small in most cultivated grapes. We crossed females and males of V. riparia that varied in domatia size and reared their offspring and found that average domatia size in the parents was highly correlated (r2 = 0.77, slope = 0.55) with average domatia size in offspring (high narrow-sense heritability). Given that V. riparia possesses many other desirable agronomic traits, this result suggests it should be practical to breed for well-developed domatia in cultivated accessions.  相似文献   

5.
Abstract

A new species of weta from mainland New Zealand is described and assigned to the previously monotypic genus Motuweta Johns and the genus redefined. Mandibles of adult males bear prominent horns. Motuweta riparia n. sp. is a moderate‐sized species (36 mm) found on the margins of first or second order streams in the eastern mid North Island ranges. Its escape reaction is to leap into the stream and remain underwater until danger has passed, a strategy which has probably enabled it to survive in predator‐infested areas.  相似文献   

6.
Corpora cardiaca of the earwigs Labidura riparia and Forficula auricularia contain a substance that causes hyperlipaemia in migratory locusts and hypertrehalosaemia in the American cockroaches. A conspecific bioassay in L. riparia revealed that this factor is lipid-mobilizing. Isolation of the neuropeptide was achieved by single-step RP-HPLC. The primary structure of the earwig adipokinetic peptide was elucidated by automated Edman degradation in combination with matrix-assisted laser desorption/ionization mass spectrometry. It is a blocked octapeptide, pGlu-Val-Asn-Phe-Ser-Thr-Gly-Trp-NH2, previously denoted as Grb-AKH and first identified in Gryllus bimaculatus ( Gäde & Rinehart 1987 ). The synthetic peptide co-chromatographed under various conditions with the native peptide and, in biological assays, resulted in lipid-mobilization in L. riparia when injected in low concentration.  相似文献   

7.
Drought induces xylem embolism formation, but grapevines can refill non‐functional vessels to restore transport capacity. It is unknown whether vulnerability to embolism formation and ability to repair differ among grapevine species. We analysed in vivo embolism formation and repair using x‐ray computed microtomography in three wild grapevine species from varied native habitats (Vitis riparia, V. arizonica, V. champinii) and related responses to measurements of leaf gas exchange and root pressure. Vulnerability to embolism formation was greatest in V. riparia, intermediate in V. arizonica and lowest in V. champinii. After re‐watering, embolism repair was rapid and pronounced in V. riparia and V. arizonica, but limited or negligible in V. champinii even after numerous days. Similarly, root pressure measured after re‐watering was positively correlated with drought stress severity for V. riparia and V. arizonica (species exhibiting embolism repair) but not for V. champinii. Drought‐induced reductions in transpiration were greatest for V. riparia and least in V. champinii. Recovery of transpiration after re‐watering was delayed for all species, but was greatest for V. champinii and most rapid in V. arizonica. These species exhibit varied responses to drought stress that involve maintenance/recovery of xylem transport capacity coordinated with root pressure and gas exchange responses.  相似文献   

8.

   

The biology of cancer is critically reviewed and evidence adduced that its development can be modelled as a somatic cellular Darwinian evolutionary process. The evidence for involvement of genomic instability (GI) is also reviewed. A variety of quasi-mechanistic models of carcinogenesis are reviewed, all based on this somatic Darwinian evolutionary hypothesis; in particular, the multi-stage model of Armitage and Doll (Br. J. Cancer 1954:8;1-12), the two-mutation model of Moolgavkar, Venzon, and Knudson (MVK) (Math. Biosci. 1979:47;55-77), the generalized MVK model of Little (Biometrics 1995:51;1278-1291) and various generalizations of these incorporating effects of GI (Little and Wright Math. Biosci. 2003:183;111-134; Little et al. J. Theoret. Biol. 2008:254;229-238).  相似文献   

9.
Abstract

Vegetation and environment in the Marche and related problems of protection. – The « Marche » region is situated in central Italy and corresponds with the natural region east of the Appennine ridge and spreading as far as the coast which is washed by the Adriatic Sea.

As to the climate, we may distinguish a coastal strip with Mesomediterranean climate with dry season, corresponding to the distribution area of Quercus ilex; a hilly strip with Submediterranean climate, corresponding to the distribution area of Quercus pubescens; a mountain strip with temperate axeric climate with sub-dry period, corresponding to the distribution area of Fagus silvatica and finally a high mountain strip with cold axeric climate, corresponding to altitude pastures. The Marche vegetation is shown in the vegetation map of Fabriano sheet (scale 1:50,000) plotted according Ozenda's vegetational series.

The following vegetation series have been plotted: submediterranean series of Quercus ilex; series of thermophilic oak wood with priority of Quercus pubescens or Quercus cerris; series of Ostrya carpinifolia; series of Quercus petraea and series of Fagus silvatica.

As far as the problems to safegard environment are concerned, a plan is given providing for the institution of 4 complete nature reserves, 34 nature reserves, and 9 regional nature parks among which those of Monte Conero, of Monti Sibillini and Monti della Laga.  相似文献   

10.
Grapevine is one of the most economically important crops in the world. Although long terminal repeat (LTR) retrotransposons are thought to have played an important role in plants, its distribution in grapevine is not clear. Here, we identified genome-wide intact LTR retrotransposons in a total of six high-quality grapevine genomes from Vitis vinifera L., Vitis sylvestris C.C. Gmel., Vitis riparia Michx. and Vitis amurensis Rupr. with an average of 2938 per genome. Among them, the Copia superfamily (particularly for Ale) is a major component of the LTR retrotransposon in grapevine. Insertion time and copy number analysis revealed that the expansion of 70% LTR retrotransposons concentrating on approximately 2.5 Ma was able to drive genome size variation. Phylogenetic tree and syntenic analyses showed that most LTR retrotransposons in these genomes formed and evolved after species divergence. Furthermore, the function and expression of genes inserted by LTR retrotransposons in V. vinifera (Pinot noir) and V. riparia were explored. The length and expression of genes related to starch metabolism and quinone synthesis pathway in Pinot noir and environmental adaptation pathway in V. riparia were significantly affected by LTR retrotransposon insertion. The results improve the understanding of LTR retrotransposons in grapevine genomes and provide insights for its potential contribution to grapevine trait evolution.  相似文献   

11.
We describe 11 new pteridophyte species belonging to various families from Bolivia: Dennstaedtiaceae:Hypolepis, scandens, Hypolepis minima; Pteridaceae:Cheilanthes glutinosa, Eriosorus angustus, E. ascendens, E. madidiensis; Tectariaceae:Tectaria jimenezii; and Woodsiaceae:Athyrium latinervatum. Diplazium bipinnatum, D. bolivianum, D. yuyoense. The following new combinations are proposed:Anemia australis, Diplazium andicola, D. andinum, andD. petiolulatum.Polystichum maximum is proposed as a new name forPolystichum giganteum.  相似文献   

12.
The relationships between the sand martin (Riparia riparia Linnaeus 1758) and the pale sand martin (Riparia diluta Sharpe et Wyatt 1893) in sympatric conditions in southern Central Siberia are discussed. New data on the distribution patterns of these two closely related martin species in the study area, the location of the breeding colonies, and nesting in mixed-species colonies are presented. Information on the morphology and habitat preferences of R. riparia and R. diluta, including conesting species, is provided. In the sympatry zone in southern Central Siberia, the pale sand martin is shown to be more abundant, with mixed colonies of R. riparia and R. diluta also being found. Both species studied differ significantly in the morphometric characters. When looking for the location of a breeding colony, R. riparia and R. diluta display different habitat requirements.  相似文献   

13.
《Journal of bryology》2013,35(2):71-87
Abstract

We classified 747 species of British and Irish mosses into 10 clusters, based on their recorded distribution in 10×10 km grid squares (hectads). We generated the clusters in a two-stage process using the CLUSTASPEC program, the method that we had earlier used for British and Irish liverworts and hornworts. The clusters are named after the species with distributions which are most similar to those of the clusters as a whole. Clusters of widespread species (Bryum capillare), southern, lowland species (Rhynchostegium confertum), widespread calcifuges (Pleurozium schreberi), upland species (Blindia acuta), and montane calcifuges (Kiaeria falcata) closely match clusters recognised in the liverworts. The remaining clusters (Tortella flavovirens, Weissia longifolia, Mnium stellare, Encalypta alpina, Mnium lycopodioides) are less similar. The classification of mosses into 15 and 20 clusters generates additional clusters of hyperoceanic and montane mosses which also resemble liverwort clusters. The influence of calcareous bedrock has a more marked effect in determining moss distributions and, unlike the liverworts, the 10 moss clusters include one which is predominantly coastal. Mosses tend to be a less upland group than liverworts; a smaller proportion of their species have northern and western distributions and the lowland clusters are characterised by more extreme environmental conditions. As with the liverworts, geographically restricted clusters of species with predominantly Mediterranean-Atlantic, Arctic-montane and Boreo-arctic Montane world ranges include marked concentrations of threatened species, and species which are not recorded as fruiting in the British Isles.  相似文献   

14.
Flourensia (Asteraceae, Heliantheae, Enceliinae) is an amphitropical genus of resinous subshrubs, shrubs and small trees with 13 North American and 20 South American species among which disagreement on the species limits of some members still exists. To resolve the taxonomy of the South American taxa, we carried out a combination of clustering (Ward's method with Gower distance coefficient) and ordination analyses (Principal Coordinate Analyses) based on 34 vegetative and reproductive characters scored from herbarium material, including types. Based on the results, we recognize 12 South American species: F. angustifolia, F. cajabambensis, F. fiebrigii, F. heterolepis, F. hirtissima, F. macrophylla, F. niederleinii; F. peruviana, F. polycephala, F. thurifera, F. tortuosa and F. suffrutescens. A number of species are placed in synonymy: Flourensia blakeana and F. hirta are synonymized under the name F. fiebrigii; Flourensia campestris, F. leptopoda, F. oolepis and F. riparia are synonymized under F. thurifera; Flourensia macroligulata is synonymized under F. tortuosa, and Flourensia polyclada is synonymized under F. suffrutescens. A taxonomic treatment of four redefined species as well as a key and distribution maps to all South American Flourensia species are provided.  相似文献   

15.
Over 200 specimens of Polyodaspis from Vietnam and Thailand (project TIGER) were studied. Variations in the color of the body and, especially, of the setae and setulae of the head, scutellum, and abdomen are demonstrated. The following new synonymy is established: Polyodaspis ruficornis (Macquart, 1835) = P. ruficornis var. tarsalis Frey, 1923, syn. n.; = P. flavipila Duda, 1934, syn. n.; = P. endogena de Meijere, 1938, syn. n.; = P. flavisetosa Nartshuk, 1991, syn. n.; = P. similis Nartshuk, 1991, syn. n.  相似文献   

16.
17.
Capsule: For declining migratory birds, including many aerial insectivores, such as swallows, there is evidence that adult survival is a demographic process with strong effects on population trends.

Aims: The aim was to identify and quantify the effect of threats affecting adult survival and potentially driving population declines for five well-studied swallow species: Barn Swallow Hirundo rustica, Cliff Swallow Petrochelidon pyrrhonota, Tree Swallow Tachycineta bicolor, Sand Martin Riparia riparia, and Purple Martin Progne subis.

Methods: We reviewed the literature to identify the threats to adult survival, quantified the magnitude of the effect and identified whether threats had a direct or indirect effect on survival.

Results: We identified habitat change, weather, competition, incidental loss, contaminants, insect availability, disease, and predation as threats to adult survival in swallows, although for many of these threats there was limited information to quantify their impact. However, weather, particularly cold snaps and precipitation, had negative effects on survival for many populations of four species, either directly or indirectly through effects on insect availability. When there was a relationship, weather was associated with a 13–53% decrease in survival.

Conclusion: Based on the available research, weather conditions throughout the annual cycle is a key threat to adult survival for several swallow species. However, future research on the threats to these species should consider examining the effect of insect availability and the effect of threats during the non-breeding period on survival. Finally, we suggest that new research should be devoted to understanding the importance of adult survival for declining bird populations.  相似文献   

18.
John F. Pruski 《Brittonia》1998,50(4):473-482
The new combinations Conyza laevigata (Astereae), Praxelis diffusa (Eupatorieae), and Riencourtia pedunculosa (Heliantheae) are made. Conyza laevigata includes C. apurensis; Praxelis diffusa includes P. pauciflora and the type of the genus, P. villosa; and Riencourtia pedunculosa includes R. glomerata and R. spiculifera, the type of the genus. Lectotypes are designated for names of five species described by Richard. The current names of other species of Compositae described by Richard in 1792 are given, including the reduction of Eupatorium incisum to Chromolaena odorata. Labeling errors are discussed, and the type of Erigeron laevigatus is taken to be from the West Indies. Riencourtia is newly documented for Bolivia and Panama.  相似文献   

19.
Summary

Saxifraga rosacea is recorded and Poa scotica described new to Scotland. The position of segregate taxa or breeding units within several species complexes is clarified within Scotland: (a) the hexaploid cytotype within the mostly tetraploid Campanula rotundifolia; (b) diploid Hedera helix and tetraploid H. hibernica;, (c) diploid and tetraploid Deschampsia cespitosa, D. alpina and D. parviflora; (d) octoploid sub-species scotica within usually hexaploid Festuca rubra; (e) an octoploid mountain Agrostis; (f) fertile hexaploid Potentilla anserina; (g) an approximately triploid aneuploid Vaccinium uliginosum ssp. microphyllum.  相似文献   

20.
2,6-Pyridinedicarbonitrile (1a) and 2,4-pyridinedicarbonitrile (2a) were hydrated by Rhodococcus erythropolis A4 to 6-cyanopyridine-2-carboxamide (1b; 83% yield) and 2-cyanopyridine-4-carboxamide (2b; 97% yield), respectively, after 10 min. After 118 h, the intermediates 1b or 2b were transformed into 2,6-pyridinedicarboxamide (1c; 35% yield) and 2,6-pyridinedicarboxylic acid (1d; 60% yield) or 2-cyanopyridine-4-carboxylic acid (2c; 64% yield), respectively. The nitrilase from Fusarium solani afforded cyanocarboxylic acids 1e and 2c after 118 h (yields 95 and 62%, respectively). 3,4-Pyridinedicarbonitrile (3a) and 2,3-pyrazinedicarbonitrile (4a) were inferior substrates of nitrile hydratase and nitrilase.  相似文献   

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