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1.
Manzoor A. Rather Bashir A. Ganai Azra N. Kamili Mubashir Qayoom Seema Akbar Akbar Masood Rafia Rasool Sajad H. Wani Mushtaq A. Qurishi 《Acta Physiologiae Plantarum》2012,34(3):885-890
The essential oil obtained by hydrodistillation from the leaves of micropropagated plants of Artemisia amygdalina was analyzed by capillary GC–FID and GC–MS and compared with that obtained from the leaves of field growing parent plants.
The oil yield from the micropropagated plants was lower (0.05% v/w) than the oil yield obtained from field-grown plants (0.2%
v/w). The major constituents of the field-grown plants were p-cymene (21.0%), 1,8-cineole (24.9%), α-terpineol (5.9%), β-caryophyllene (4.7%), germacrene D (4.0%), while as the major
constituents from the micropropagated plants were p-cymene (11.3%),1,8-cineole (10.2%), borneol (7.9%), α-longipinene (5.5%), α-copaene (5.5%) and β-caryophyllene (17%). The
essential oil from field-grown plant was dominated by the presence of oxygenated monoterpenes (41.5%), monoterpene hydrocarbons
(35.9%) and sesquiterpene hydrocarbons (16.3%) while as the essential oil of micropropagated plants was characterized by sesquiterpene
hydrocarbons (40.0%), oxygenated monoterpenes (25.2%) and monoterpene hydrocarbons (21.6%). 相似文献
2.
Militello M Settanni L Aleo A Mammina C Moschetti G Giammanco GM Blàzquez MA Carrubba A 《Current microbiology》2011,62(4):1274-1281
This study was undertaken to characterize the essential oil (EO) of Artemisia arborescens growing wild in Sicily. EO, extracted by steam distillation, was examined for its chemical composition and for its capability
to inhibit some food-borne pathogen bacteria. A total of 43 compounds (13 monoterpene hydrocarbons, 14 oxygenated monoterpenes,
10 sesquiterpene hydrocarbons, three oxygenated sesquiterpenes and less amount of other three compounds), which account 93.73%
of the total oil, were identified by gas chromatography and gas chromatography–mass spectrometry. Oxygenated monoterpenes
(57.32%) constituted the main fraction, with β-thujone as the main compound (45.04%), followed by the sesquiterpene hydrocarbon
chamazulene (22.71%). Undiluted EO showed a large inhibition spectrum against strains of Listeria monocytogenes (34 out of 44), whilst it was ineffective against enterobacteria and salmonellas. The minimum inhibition concentration (MIC)
was evaluated for the two most sensitive strains (L. monocytogenes 186 and 7BO) at two cellular concentrations (106 and 107 CFU ml−1). The lowest MIC (0.625 μl ml−1, dilution of oil with acetone) was found for strain L. monocytogenes 186 at 106 CFU ml−1. 相似文献
3.
Inhibitory Activity and Chemical Characterization of Daucus carota subsp. maximus Essential Oils
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Raimondo Gaglio Marcella Barbera Aurora Aleo Ines Lommatzsch Tommaso La Mantia Luca Settanni 《化学与生物多样性》2017,14(5)
The essential oils (EOs) of green seeds from Daucus carota subsp. maximus growing wild in Pantelleria Island (Sicily, Italy) were characterized. EOs were extracted by steam distillation, examined for their inhibitory properties against food‐borne Gram‐positive and Gram‐negative bacteria and analyzed for the chemical composition by gas chromatography (GC) and mass spectrometry (MS). Undiluted EOs showed a large inhibition spectrum against Gram‐positive strains and also vs. Acinetobacter spp. and Stenotrophomonas maltophilia. The minimum inhibition concentration (MIC) was in the range 1.25 – 2.50 μl/ml for the most sensitive strains. The chemical analysis indicated that D. carota subsp. maximus EOs included 34 compounds (five monoterpene hydrocarbons, six oxygenated monoterpenes, 14 sesquiterpene hydrocarbons, four oxygenated sesquiterpenes, camphorene and four other compounds), accounting for 95.48% of the total oil, and that the major chemicals were carotol, β‐bisabolene, and isoelemicin. 相似文献
4.
Srdjan Bojović Maja Jurc Mihailo Ristić Zorica Popović Rada Matić Vera Vidaković Milena Stefanović Dušan Jurc 《化学与生物多样性》2016,13(2):181-187
The composition and variability of the terpenes and their derivatives isolated from the needles of a representative pool of 114 adult trees originating from four natural populations of dwarf mountain pine (Pinus mugo Turra ) from the Julian Alps were investigated by GC‐FID and GC/MS analyses. In total, 54 of the 57 detected essential‐oil components were identified. Among the different compound classes present in the essential oils, the chief constituents belonged to the monoterpenes, comprising an average content of 79.67% of the total oil composition (74.80% of monoterpene hydrocarbons and 4.87% of oxygenated monoterpenes). Sesquiterpenes were present in smaller amounts (average content of 19.02%), out of which 16.39% were sesquiterpene hydrocarbons and 2.62% oxygenated sesquiterpenes. The most abundant components in the needle essential oils were the monoterpenes δ‐car‐3‐ene, β‐phellandrene, α‐pinene, β‐myrcene, and β‐pinene and the sesquiterpene β‐caryophyllene. From the total data set of 57 detected compounds, 40 were selected for principal‐component analysis (PCA), discriminant analysis (DA), and cluster analysis (CA). The overlap tendency of the four populations suggested by PCA, was as well observed by DA. CA also demonstrated similarity among the populations, which was the highest between Populations I and II. 相似文献
5.
Mints are the most popular economic and traditional herbs. The aim of this article was chemical characterization of volatile compounds from wild populations of Mentha aquatica, M. arvensis, M. longifolia, M. microphylla, M. pulegium, M. spicata, M.×dumetorum, M.×gentillis and M.×verticillata, as well as cultivated samples of M. spicata, M.×piperita ‘Alba’ and M.×piperita ‘Crispa’. Analyses were performed directly from dried aerial parts (herb) of collected samples by headspace gas chromatography‐mass spectrometry. In total 54 compounds were detected, representing from 89.99 % to 99.66 % of volatile fractions of all investigated samples. The recorded volatiles were primarily monoterpene hydrocarbons and oxygenated monoterpenes, while oxygenated aromatic monoterpenes, sesquiterpene hydrocarbons and aliphatic compounds were present in lower concentrations in analyzed samples. The major components were linalool, limonene, 1,8‐cineol, α‐terpinyl acetate, pulegone, β‐pinene and menthol. The cluster analysis revealed five main groups or chemotypes according to qualitative and quantitative content of volatiles, as well as similarities among samples. These results contribute to the knowledge on the mints chemistry in Pannonian Plain and Balkan Peninsula. 相似文献
6.
The effect of the collection sites and phenophase on yield and chemical composition of Salvia verbenaca essential oils was evaluated. The essential oil constituents were assessed by gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS). The highest essential oil yields were observed for samples of the higher semi-arid bioclimate and at the flowering period. Eighty-five volatile constituents were identified and their percentages varied significantly (p < 0.05) depending on the collection site and the phenological stage. According to the plants origin, essential oils were dominated by monoterpene hydrocarbons, oxygenated monoterpenes and sesquiterpene hydrocarbons. The monoterpene hydrocarbons (31.9%) predominate at the flowering stage whereas oxygenated sesquiterpenes (27.5%) at the early fruiting stage. The sesquiterpene hydrocarbons (28.2%) was the most represented chemical class at late fruiting. On the basis of GC-MS data, the major identified volatile constituents were viridiflorol (3.4–17.7%), α-pinene (0.7–15.9%), β-caryophyllene (1.0–15.3%) and p-cymene (1.3–14.2%). S. verbenaca contains a diversity of bioactive constituents which shows large variations as affected by the collection sites and phenophase. 相似文献
7.
Michele Leonardi Katarzyna E. Ambryszewska Bernardo Melai Guido Flamini Pier Luigi Cioni Federico Parri Luisa Pistelli 《化学与生物多样性》2013,10(3):343-355
The composition of 21 essential‐oil samples isolated from Helichrysum italicum collected in seven locations of Elba Island (Tuscany, Italy), characterized by different soil types, during three different periods (January, May, and October 2010) was determined by GC‐FID and GC/EI‐MS analyses. In total, 115 components were identified, representing 96.8–99.8% of the oil composition. The oils were characterized by a high content of oxygenated monoterpenes (38.6–62.7%), while monoterpene and sesquiterpene hydrocarbons accounted for 2.3–41.9 and 5.1–20.1% of the identified constituents, respectively. The main oxygenated derivatives were nerol (2.8–12.8%) and its ester derivative neryl acetate (5.6–45.9%). To compare the chemical variability of the species within Elba Island and between the island and other localities within the Mediterranean area, studied previously, multivariate statistical analysis was performed. The results obtained showed a difference in the composition of the essential oils of H. italicum from Elba Island, mainly due to the environment where the plant grows, and, in particular, to the soil type. These hypotheses were further confirmed by the comparison of these oils with essential oils obtained from H. italicum collected on other islands of the Tuscan archipelago. 相似文献
8.
Juniperus oxycedrus L. (Cupressaceae Bartlett) is widely distributed in countries with a Mediterranean climate. All plant parts contain highly aromatic essential oil (EO) and recently there have been efforts to introduce it as a cultivated crop. The species is known for its large morphological and chemical variation and its debatable taxonomic status. This study aimed to (1) compare content, composition, and antimicrobial activity of J. oxycedrus EO samples from plants growing in Bulgaria and Serbia, and (2) quantify morphological variations of leaves. Тhe EO content (yield) in dried juniper leaves varied from 0.06% (Кopaonik, Serbia) to 0.24% (Markovo, Bulgaria). We identified 51 EO constituents, belonging to monoterpenes, sesquiterpenes, and diterpenes. The class monoterpenes (monoterpene hydrocarbons and oxygenated monoterpenes) were the predominant compounds, representing 38.6–65.4% of the total EO, consisting primarily of α-pinene, limonene, sabinene, β-pinene, and β-myrcene. In addition, α-pinene was the major oil constituent in plants from all locations. Sesquiterpenes (sesquiterpene hydrocarbons and oxygenated sesquiterpenes) were the second largest class of constituents, which represented 19.3% tо 33.6% of the total EO. γ-Elemene was found only in the EO of J. oxycedrus from Bulgaria, while a high concentration of α-curcumene was found only in samples from Serbia (7.5–7.8%). Significant differences in antimicrobial activity of the EO were found in bacterial strains Bacillus cereus and Streptococcus pneumoniae. There was no significant difference among the mean leaf width of the six combinations location x sex, and the overall leaf mean width was 1.24 mm. However, there was a significant difference between the mean leaf lengths. In this study, none of the studied populations had a higher concentration of limonene than of α-pinene, indicating that the flora of the two countries include J. oxycedrus and not the previously reported J. deltoides. The results revealed significant variation in EO profile that may contribute to the development of new cultivars of J. oxycedrus. 相似文献
9.
Andrés Campoy Lidia Sáez Celeste Pérez-Bañón Santos Rojo 《Journal of Applied Entomology》2020,144(1-2):133-143
The importance of eristaline flies (Diptera, Syrphidae, Eristalini) as pollinators in natural ecosystems and for agricultural crops is well known. However, in-depth studies on the life cycle of most of these species have yet to be carried out. The aim of this research was to study the life cycle of Eristalis tenax (Linnaeus, 1758) and Eristalinus aeneus (Scopoli, 1763) in order to improve the current rearing system employed at the University of Alicante. The results were analysed using the age-stage, two-sex life table method. As one of the main results, the mean duration of the life history of E. tenax and E. aeneus was 46.06 and 65.12 days (d), respectively. The most critical step for both species was found at the beginning of the larval stage (first instar), when the highest mortality was recorded. Population parameters were also analysed and compared. The intrinsic rate of increase (r), the finite rate of increase (λ), the net reproductive rate (R0) and the mean generation time (T) were 0.09 (d−1), 1.09 (d−1), 42.11 offspring and 40.97 d, in the case of E. aeneus and 0.05 (d−1), 1.05 (d−1), 23.13 offspring and 59.23 d, in the case of E. tenax. These results indicate that the current rearing system is more efficient for E. aeneus, which displays a faster population growth. However, some modifications need to be implemented to improve the production of E. tenax. 相似文献
10.
Two 60-day experiments were conducted to study the influence of photon flux density (PFD) and temperature on the attachment
and development of Gloiopeltis tenax and Gloiopeltis furcata tetraspores. In the first experiment, tetraspores of the two Gloiopeltis species were incubated at five temperature ranges (8°C, 12°C, 16°C, 20°C, 24°C) under a constant PFD of 80 μmol photons m−2 s−1 with a photoperiod of 12:12. In a second experiment, tetraspores were incubated under five PFD gradients (30, 55, 80, 105,
130 μmol photons m−2 s−1) at a constant temperature of 16°C with a photoperiod of 12:12. Maximum density of attached tetraspores was observed at 16°C
for both species. Maximum per cent of spore germinating into disc was recorded at 12–16°C for G. tenax and 8–12°C for G. furcata. Maximum per cent of discs producing erect axes for G. tenax and G. furcata were recorded at 24°C and 20°C, respectively. Light had no significant effect on tetraspore attachment and developing into
disc, but it affected the growth, sprouting and survival of its discs. Under 30–55 μmol photons m−2 s−1, the discs of the two species of Gloiopeltis did not form thallus until the end of the experiment. Optimum PFD range for G. tenax discs was 80–105 μmol photons m−2 s−1, whilst it was 80–130 μmol photons m−2 s−1 for G. furcata. Results presented in this study are expected to assist the progress of artificial seeding of Gloiopeltis. 相似文献
11.
《Saudi Journal of Biological Sciences》2020,27(7):1900-1906
The essential oil (EO) of Bassia muricata shoots was extracted via hydro-distillation and then investigated by gas chromatography-mass spectrometry. Thirty-four compounds were recognized for the first time from this plant, representing 100% of the total mass. Terpenoids represented the major components with 69.17% of the total mass, containing oxygenated sesquiterpenes (53.18%), oxygenated monoterpenes (9.77%), sesquiterpene hydrocarbons (5.03%), and diterpenes (1.19%). Additionaly, 6-methoxy-1-acetonaphthone was the only aromatic compound represented in a high percentage of the total identified compounds with 22.35%. Additionally, a percent of 8.48% of the total mass was hydrocarbons. Only one oxygenated sesquiterpene namely hexahydrofarnesyl acetone representing 47.35% of the total mass was identified. It was followed by methoxy-1-acetonaphthone (19.92%), n-dotriacontane (3.58%), endo-borneol (3.24%), 6-methy-α-ionone (3.04%), and α-gurjunene (2.65%). The EO exhibited moderate antioxidant activity comparable with ascorbic acid as a standard, where it attained IC50 value of 20.70 µL L−1 and 16.32 µL L−1, for DPPH and ABTS. The EO of B. muricata significantly reduces the germination and seedling development of the weed Chenopodium murale. The EO showed an IC50 value of 175.60 µL L−1, 246.65 µL L−1, and 308.33 µL L−1 for root growth, shoot growth, and germination, respectively. Therefore, this EO could be a good green resource for the control of weeds. 相似文献
12.
Molecular phylogenetic analyses indicate paraphyly of the genus Hybomys (Rodentia: Muridae): Taxonomic implications
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Alain Didier Missoup Ghislain D. Yemchui Christiane Denys Violaine Nicolas 《Journal of Zoological Systematics and Evolutionary Research》2018,56(3):444-452
Widely distributed in Guineo‐Congolian forests, the genus Hybomys is represented by two species complexes (univittatus and trivirgatus), each restricted to one distinct forest block. In the last revision, these two species complexes were considered as distinct subgenera (Hybomys and Typomys). Previous morphological and karyological studies identified an important divergence between these two subgenera and raised the question of their taxonomic status (subgenus or genus). The number of species within this genus is also a matter of discussion: nine forms were described but only six (H. badius, H. basilii, H. lunaris, H. planifrons, H. trivirgatus, and H. univitttatus) are currently recognized as distinct species, the three others (H. pearcei, H. eisentrauti, and H. rufocanus) being considered as synonyms. The monophyly of the genus and its species have never been previously investigated with DNA sequence data. In this study, we combined mitochondrial and nuclear data (for a total of 3,264 nucleotide characters) to test the monophyly of Hybomys and to assess the specific status of H. eisentrauti and H. rufocanus. Our results highlight the paraphyly of the genus: members of the H. univittatus species complex appeared closely related to the genera Stochomys and Dephomys; representatives of H. trivirgatus are the sister clade of the node grouping Stochomys, Dephomys and member of the H. univittatus species complex. Combined with previous morphological findings, our results suggest that Typomys and Hybomys should be considered as two distinct genera. Based on tree topology and genetic distances, we propose to consider H. rufocanus as a valid species, distinct from H. univittaus, and to consider H. badius and H. eisentrauti as junior synonyms of H. rufocanus. 相似文献
13.
Functional characterization of terpene synthases and chemotypic variation in three lavender species of section Stoechas
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Tarek Benabdelkader Yann Guitton Bernard Pasquier Jean Louis Magnard Frédéric Jullien Abdelkrim Kameli Laurent Legendre 《Physiologia plantarum》2015,153(1):43-57
Lavandula pedunculata (Mill.) Cav. subsp. lusitanica, Lavandula stoechas L. subsp. stoechas and Lavandula viridis l'Hér. are three lavender taxa that belong to the botanical section Stoechas and are widely used as aromatherapy, culinary herb or folk medicine in many Mediterranean regions. The analysis of their bioactive volatile constituents revealed the presence of 124 substances, the most abundant being the bicyclic monoterpenes fenchone, camphor and 1,8‐cineole that give these three species their respective chemotypes. Most noteworthy was fenchone which, with its reduced form fenchol, made 48% of the total volatile constituents of L. pedunculata while present at 2.9% in L. stoechas and undetectable in L. viridis. In order to provide a molecular explanation to the differences in volatile compounds of these three species, two monoterpene synthases (monoTPS) and one sesquiterpene synthase (sesquiTPS) were cloned in L. pedunculata and functionally characterized as fenchol synthase (LpFENS), α‐pinene synthase (LpPINS) and germacrene A synthase (LpGEAS). The two other lavender species contained a single orthologous gene for each of these three classes of TPS with similar enzyme product specificities. Expression profiles of FENS and PINS genes matched the accumulation profile of the enzyme products unlike GEAS. This study provides one of the rare documented cases of chemotype modification during plant speciation via changes in the level of plant TPS gene expression, and not functionality. 相似文献
14.
The aroma emitted from the different organs of two Salvia verbenaca L. populations from Jordan were extracted by Solid Phase Micro‐Extraction (SPME) and then analyzed by GC/MS. The emission profile of the stem, leaf and sepal samples from the Mediterranean zone (Al‐Salt) was dominated by monoterpene hydrocarbons (68.0 %, 33.7 %, and 42.2 %, respectively). The emission profile of flowering parts including pre‐flowering buds, fully expanded flowers and petals was dominated by oxygenated monoterpenes (58.6 %, 59.3 % and 87.1 %, respectively). The major constituent detected in these organs was trans‐sabinene hydrate acetate (range 14.5 %–87.0 %). On the other hand, samples collected from Irano‐Turanian zone showed different emission patterns. While the stems, leaves and petal emissions were dominated by sesquiterpene hydrocarbons (54.9 %, 76.8 % and 52.6 %, respectively), monoterpene hydrocarbons dominated the emission profiles of the pre‐flowering buds (75.1 %) and fully expanded flowers (73.6 %). Petals emissions were characterized by high concentrations of oxygenated monoterpenes (58.8 %). Notably, trans‐sabinene hydrate dominated most organs emissions except for leaves (range 20.0 %–58.8 %). Principle Component Analysis (PCA) and Cluster Analysis (CA) revealed two different clusters related to the two different geographical zones. The current investigation revealed two ecotypes of S. verbenaca that could result in two different chemotypes. Trans‐sabinene hydrate acetate and trans‐sabinene hydrate are suggested compounds for identifying these two chemotypes. 相似文献
15.
Noemí Sánchez Alba Vergés César Peteiro Judith E. Sutherland Juliet Brodie 《Journal of phycology》2014,50(5):908-929
The diversity of the bladed species of the red algal order Bangiales from the Iberian Mediterranean shores has been reassessed after a detailed study of this region. Prior to this study, 11 bladed species of Bangiales had been reported from Mediterranean waters: Porphyra atropurpurea, P. cordata, P. coriacea, P. dioica, P. linearis, P. purpurea, P. umbilicalis, Pyropia leucosticta, Pyropia koreana (as P. olivii), Py. elongata (as P. rosengurttii) and Py. suborbiculata. A combined analysis of the nuclear nSSU and the plastid rbcL genes together with detailed morphological studies has confirmed the presence of species within the genera Porphyra and Pyropia and also revealed a third, undescribed genus, Themis gen. nov. Porphyra linearis, Pyropia elongata and the introduced Pyropia koreana had been previously listed for the Mediterranean and were recorded in this study. An additional four species, including the introduced Pyropia suborbiculata and three new species: Pyropia parva sp. nov., Themis ballesterosii sp. nov., and Themis iberica sp. nov. were also observed. Hence, most of the Porphyra species traditionally reported along these shores were not reported in this survey. This new floristic Bangiales composition confirms the importance of the Mediterranean basin as a hotspot for biodiversity, possible endemics of ancient origin and high proportion of introductions. Our data also continue to confirm the extent of Bangiales diversity at regional and worldwide levels. 相似文献
16.
Larry V. Padilla Maria Lourdes San Diego-McGlone Rhodora V. Azanza 《Journal of applied phycology》2010,22(6):761-768
Harmful algal bloom occurrences worldwide have prompted the testing and use of methods to control and mitigate their detrimental
effects. This study investigates the potential of Philippine clay minerals to physically remove phytoplankton cells under
laboratory conditions. Ball clay had the highest removal efficiency (∼95%) for Pyrodinium bahamense (paralytic shellfish poisoning causative organism) cells. A slight decrease in the efficiency by 10–20% was seen when culture
volume was increased from 50 mL to 1 L. Removal efficiency was reduced to ∼95% when water motion was introduced. Removal of
other phytoplankton species (Gymnodinium sanguineum, Amphidinium carterae, Pyrophacus horologium, Chatonella marina, and Alexandrium sp.) using ball clay was less efficient (<70%). Cell removal efficiencies differed with phytoplankton species belonging to
the same taxonomic group. Possible mechanisms for cell removal are described. 相似文献
17.
Noriyuki Ito Naoyuki Itoh Rikako Nakanishi Satoshi Kameshima Yuya Kimura 《The Journal of eukaryotic microbiology》2023,70(1):e12941
This study investigated the molecular prevalence of oral trichomonads in household dogs. Of the 144 dogs, 21 (14.6%, 21/144) tested positive for oral trichomonads. The prevalence was significantly higher in dogs with severe gingivitis (gingival index 3: 30.0%, 8/26) than that in normal dogs (gingival index 0: 2.7%, 1/37). Therefore, an interaction between oral trichomonads and the development of periodontal disease is suggested. Of the 21 positive samples, 16 isolates were T. brixi, four isolates were T. tenax, and one was Tetratrichomonas sp. Considering T. tenax is recognized as a zoonotic agent, transmission between dogs and humans cannot be neglected. 相似文献
18.
19.
Norio Kobayashi Momoko Kumagai Daisuke Minegishi Koichiro Tamura Tadashi Aotsuka Haruo Katakura 《Journal of Zoological Systematics and Evolutionary Research》2011,49(1):16-24
To clarify evolutionary relationships and assess the intensity and persistence of reproductive isolation because of host fidelity in three closely related host‐associated phytophagous ladybird beetles (Henosepilachna pustulosa, Henosepilachna niponica and Henosepilachna yasutomii), we determined sequences of part of the nuclear DNA internal transcribed spacer‐II (ITS‐2) region (388 bp long) for 70 individuals from seven populations, and part of the mitochondrial cytochrome c oxidase subunit I (COI) gene (985 bp long) for 280 individuals from 28 populations across the three species. We failed to detect any polymorphic sites in the ITS‐2 region. We detected 59 COI haplotypes, among which two were shared by different species. While a haplotype network and a phylogenetic gene tree of the COI haplotypes did not support monophyly for any of the three species, the results of AMOVA did not invalidate the classification of these beetles into three species. The isolation‐with‐migration analytic (IMa) test suggested that gene flow between allopatric species (i.e., H. pustulosa versus H. niponica; H. pustulosa versus H. yasutomii) was well prevented, probably because of their limited dispersal power. On the other hand, the IMa test detected a low level of unidirectional gene flow between the sympatric species H. niponica and H. yasutomii, from the former to the latter. This result was consistent with a survival rate of F1 hybrids between the two species that is higher on the host plant of H. yasutomii than on the host plant of H. niponica. High FST values among two sympatric and three nearly sympatric population pairs of H. niponica and H. yasutomii, however, indicated that gene flow between the two species has been quite restricted even if it has occurred. Because no reproductive barriers other than the difference in host plants is known for sympatric H. niponica and H. yasutomii, our results suggest that host differentiation and associated ecological divergence function as an effective reproductive barrier between the two species. 相似文献
20.
Fire is an ecological factor that has been present in the ecosystems of the Mediterranean region for thousands of years. Our
study was undertaken to acquire knowledge of the effect of fire on the germination of Mediterranean species. We used high
temperatures (up to 60°C) and smoke to determine the effect of these factors on the germination of species from the Mediterranean
region. The species selected are characteristic of the central Mediterranean basin and are representative of both woody and
herbaceous species: Rhamnus alaternus L., Cistus albidus L., Cistus monspeliensis L., Fumana ericoides (Cav.) Gand., Rosmarinus officinalis L., Melica ciliata L., Avena sterilis L., Bituminaria bituminosa (L.) C.H. Stirt., Anthyllis vulneraria L., Coronilla glauca L., Argyrolobium zanonii (Turra) P.W. Balland, Emerus major Mill., Genista scorpius (L.) D.C. and Spartium junceum L. The seeds were collected in Mediterranean shrubland (8) and woodland (6) ecosystems, around Montpellier, France (24°45′N
and 3°50′E). Ten treatments were tested: a control, three smoke treatments and six heat treatments. The average germination
level (germination percentage) and the average T50 rates (time taken to reach 50% of germination) were calculated. The smoke and heat act in a different way on each of the
species. The smoke enhanced the germination of two species, whilst moderate heat increased germination in all of the species
excepting R. officinalis, F. ericoides, A. sterilis, A. vulneraria, and G. scorpius. Germination was fastest in M. ciliata and S. junceum and slowest in A. sterilis, E. major and C. albidus. The cues did not significantly affect the rate of germination. Fire modified the germination response of 12 of the 14 species
studied. 相似文献