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1.
We studied the effects of differences in root growth and nutrient pool on the competitive ability of Festuca ovina (short grass), Arrhenatherum elatius and Calamagrostis epigejos (tall grasses) grown in monocultures and in mixtures of homogeneous and heterogeneous environments during two growing seasons.
Analysis of variance revealed a significant effect of plant species on nutrient concentrations in above-ground biomass and
of substrate type on contents of N, K, Ca, Mg in biomass. The ANOVA also confirmed the significant effect of competitive environment
on the concentration of N, K in above-ground biomass. In heterogeneous environments, both tall grasses (in competition with
F. ovina) were able to produce more roots in the nutrient-rich patches and to accumulate more nitrogen in plant tissues, which was
associated with higher yield of their above-ground biomass. Thus, the relative competitive ability for nutrients of both tall
grasses was higher than that of F. ovina. This competitive ability of A. elatius to C. epigejos increased in heterogeneous treatments. 相似文献
2.
Paul M. Severns 《Journal of Insect Conservation》2008,12(6):651-661
Fender’s blue butterfly is an endangered species restricted to fragmented, grassland remnants that are becoming increasingly
dominated by tall, invasive grasses in western Oregon, USA. I performed a removal experiment to assess the impacts of structural
degradation accompanying the invasion of Arrhenatherum elatius, tall oat grass, on butterfly fitness and fitness related behaviors. Clipping of A. elatius to native grass sward height resulted in 2.5–5 times as many eggs laid per leaf of host plant. Both male and female butterflies
basked more frequently in areas removed of A. elatius inflorescences and upon encountering the treatment edge butterflies had a high rate of return into a large area removed of
the grass inflorescences. Although butterfly behavior appeared to be affected by the change in sward height on the treatment
edge, there was no evidence for the edge causing a disproportionate egg load. Invasion and dominance by A. elatius appeared to diminish host plant apparency which may result in overloading of eggs on conspicuous host plants, increased incidence
of emigration, and a decrease in the likelihood of colonization because female butterflies appeared indifferent to larval
resources beneath A. elatius inflorescences. Dominance of natural shortgrass prairies by tall stature grasses like A. elatius may be an insidious form of habitat degradation for grassland Lepidoptera worldwide, but it may go largely unnoticed because
larval and adult resources can persist under the unnaturally tall grass canopy. 相似文献
3.
Enhanced nitrogen (N) levels accelerate expansion of Calamagrostis epigejos and Arrhenatherum elatius, highly aggressive expanders displacing original dry acidophilous grassland vegetation in the Podyjí National Park (Czech
Republic). We compared the capability of Calamagrostis and Arrhenatherum under control and N enhanced treatments to (i) accumulate N and phosphorus (P) in plant tissues, (ii) remove N and P from
above-ground biomass during senescence and (iii) release N and P from plant material during decomposition of fresh formed
litter. In control treatment, significantly higher amounts of total biomass and fresh aboveground litter were observed in
Calamagrostis than in Arrhenatherum. Contrariwise, nutrient concentrations were significantly higher (11.6–14.3 mg N g−1 and 2.3 mg P g−1) in Arrhenatherum peak aboveground biomass than in Calamagrostis (8.4–10.3 mg N g−1 and 1.6–1.7 mg P g−1). Substantial differences between species were found in resorption of nutrients, mainly P, at the ends of growing seasons.
While P concentrations in Arrhenatherum fresh litter were twice and three times higher (1.6–2.5 mg P g−1) than in Calamagrostis (0.7–0.8 mg P g−1), N concentrations were nearly doubled in Arrhenatherum (13.1–15.6 mg N g−1) in comparison with Calamagrostis (7.4–8.7 mg N g−1). Thus, the nutrients (N and mainly P) were retranslocated from the aboveground biomass of Calamagrostis probably more effectively in comparison with Arrhenatherum at the end of the growing season. On the other hand, Arrhenatherum litter was decomposed faster and consequently nutrient release (mainly N and P) was higher in comparison with Calamagrostis which pointed to different growth and nutrient use strategies of studied grass species. 相似文献
4.
The effectiveness of the predatory mite Typhlodromus pyri and of an application of Polysulphide-Ca was compared during 2006–2008. The experiment showed differences in infestation
levels of pear leaves caused by Eriophyes pyri. The highest percentage of leaves with symptoms was found in untreated control group (⊘ 20.9%); the lowest percentage was
found in plots treated with T. pyri (⊘ 3.7%); and a slightly higher percentage was found in plots treated with Polysulphide-Ca (⊘ 8.6%). During 2006–2008 the
percentage of leaves with symptoms was approximately the same only in the untreated control plots (from 20.3% to 21.5%). The
percentage of leaves with characteristic symptoms in plots treated with T. pyri decreased from 5.5% in 2006 to 4.3% in 2007, and to 1.3% in 2008. On the other hand, the percentage of leaves with symptoms
in plots treated with Polysulphide-Ca increased from 5.5% in 2006 to 8.5% in 2007, and to 11.8% in 2008. The intensity of
symptoms on infested leaves was also different depending on treatments and years. The average biological activity was 82.4%
in plots receiving releases of T. pyri and 58.8% in plots treated with Polysulphide-Ca. 相似文献
5.
Moslem Papizadeh Mohammad Roayaei Ardakani Gholamhossein Ebrahimipour Hossein Motamedi 《World journal of microbiology & biotechnology》2010,26(7):1195-1200
Oil-polluted soils were sampled from National Iranian South Oil Company (NISOC) for isolation and screening of C–S and not
C–C targeted Dibenzothiophene (DBT) degrading microorganisms. Microbacterium sp. NISOC-06, a C–S targeted DBT degrading bacterium, was selected and its desulfurization ability was studied in aqueous phase and water-gasoline
biphasic systems. The 16srRNA gene was amplified using universal eubacteria-specific primers, PCR product was sequenced and
the sequence of nearly 1,500 bp 16srDNA was studied. Based on Gas Chromatography results Microbacterium sp. NISOC-06 utilized 94.8% of 1 mM DBT during the 2 weeks of incubation. UV Spectrophotometry and biomass production measurements showed
that the Microbacterium sp. NISOC-06 was not able to utilize DBT as a carbon source. There was no accumulation of phenolic compounds as Gibb’s assay showed. Biomass
production in a biphasic system for which DBT-enriched gasoline was used as the sulfur source indicated the capability of
Microbacterium sp. NISOC-06 to desulfurize gasoline. 相似文献
6.
Agnieszka M. Bogdanowicz Paweł Olejniczak Marlena Lembicz Waldemar Żukowski 《Central European Journal of Biology》2011,6(5):870-877
We tested a hypothesis based on life history theory that examines reproductive costs incurred by individuals in consecutive
years of their life. A multi-year dataset of resource allocation to vegetative and reproductive structures was analysed in
Carex secalina — a perennial, monoecious sedge, reproducing only sexually. In a four-year garden experiment, we assessed above-ground biomass
at the end of each season and reproductive allocation expressed as the total length of male and female spikes. The study was
aimed at determining how size and age of a plant relates to its reproduction, and how the rate of reproduction affects the
year-toyear biomass change in Carex secalina. We observed that after each reproductive episode, individuals had significantly smaller sizes and produced a lower number
of generative tillers. The total production of reproductive structures decreased significantly with age in all populations.
Moreover, the decrease in plant biomass was greater when more reproductive structures were produced in a previous year, which
indicates that the plants incur costs of reproduction in terms of above-ground biomass production. 相似文献
7.
Osvaldo Di Iorio Paola Turienzo Santiago Nava Mariano Mastropaolo Atilio J. Mangold Daniel González Acuña Alberto A. Guglielmone 《Experimental & applied acarology》2010,51(4):419-422
Argas neghmei Kohls & Hoogstraal is a Neotropical tick species parasite of poultry and man in the arid western of the southern cone of
America in Argentina and Chile. Males, females and nymphs of an argasid were collected from 20 to 22 of June, 2007 in nests
of Creamy-breasted Canastero, Asthenes dorbignyi (Reinchenbach) (Passeriformes: Furnariidae) at about 7 km S of La Poma (24°46′S, 66°12′W) and a male tick at 24°48′S, 66°10′W
on Nov 27, 2008, Salta province, Argentina. Scanning electron microscope micrographies and sequences of 16S rDNA confirmed
that the ticks found were A. neghmei. Development in breeding areas of A. dorbignyi is probably a source of infestation for animal premises and houses. However, the role of other unknown wild birds may also
contribute to the invasion of A. neghmei in chicken houses or residences. 相似文献
8.
Summary. The paper describes two methods of the synthesis of ethyl (3R,4S)- and (3S,4S)-4-[(benzyloxycarbonyl)amino]-5-[(tert-butyloxycarbonyl)amino]-3-hydroxypentanoates, useful for the syntheses of edeine analogs. Differently N-protected (S)-2,3-diaminopropanoic acid was used as a substrate in both procedures. The absolute configuration of newly generated asymmetric
carbon atoms C-3 in β-hydroxy-γ,δ-diamino products was assigned by means of 1H NMR spectroscopy after their transformation into corresponding piperidin-2-ones.
Received May 24, 2002 Accepted October 10, 2002 Published online December 18, 2002
Acknowledgment The authors are indebted to the Faculty of Chemistry, Technical University of Gdańsk for financial support.
Authors' address: Zbigniew Czajgucki, M. Sc., Department of Pharmaceutical Technology and Biochemistry, Faculty of Chemistry, Technical University
of Gdańsk, 11/12 Narutowicza St., 80-952 Gdańsk, Poland, Fax +48 58 347 11 44, E-mail: zmczaj@wp.pl 相似文献
9.
Wang Minqin Zhao Junsheng Peng Zhenying Guo Wei Wang Yun Wang Le Xia Guangmin 《Plant Cell, Tissue and Organ Culture》2008,92(2):121-130
In order to investigate chromosome elimination in symmetric somatic hybridization between Bupleurum scorzonerifolium and Arabidopsis thaliana, protoplasts were isolated from suspension cultures of both A. thaliana and B. scorzonerifolium parents. Biparental protoplasts were mixed at a rate of 1.5:1 and fused with PEG-method. After protoplast fusion, the products
were cultured in the P5 liquid medium for microcallus formation. Single cell lines formed from microcalli after subculturing
on the MB1 (Xia and Chen, Plant Sci 120:197–203, 1996) solid medium. The putative somatic hybrid cell lines were identified
by cytological and molecular analysis. Of the 132 somatic cell lines generated, 16 were identified as somatic hybrids, with
the phenotypes resembled B. scorzonerifolium parent. These hybrids showed a complete set of B. scorzonerifolium chromosome and 0–2 small chromosome(s) of A. thaliana. A few of them showed nuclear and cytoplasmic SSR fragments of A. thaliana. These hybrid cell lines could differentiate to green spots, buds/leaves through complementation of regeneration ability.
The chromosomes elimination of A. thaliana was discussed.
Wang Minqin and Zhao Junsheng contributed equally to the work. 相似文献
10.
Anamélia de Souza Jesus Hugo Eduardo Schunemann Jackson Müller Moira Ansolch da Silva Júlio César Bicca-Marques 《Primates; journal of primatology》2010,51(3):227-230
Hybridization between Alouatta spp. has been suggested at contact zones of A. palliata and A. pigra in Mexico and of A. caraya and A. guariba clamitans in Brazil and Argentina. Whereas genetic data confirmed hybridization between the former pair of species, hybrid individuals
of the latter pair have been putatively identified on the basis of a mosaic pelage color. In this paper, we describe the first
confirmed cases of hybridization between a female A. guariba clamitans and a male A. caraya. One hybrid male was born in 2007 and one hybrid female was born in 2009 with distinct coat colors. The male resembled the
newborn color pattern characteristic of A. guariba clamitans, whereas the female resembled the newborn pattern of A. caraya. The birth and survival of the male hybrid for a year and a half indicated the viability of the heterogametic sex. 相似文献
11.
E. B. Kirichenko Yu. V. Orlova D. V. Kurilov 《Russian Journal of Plant Physiology》2008,55(6):846-853
Abstrac The composition of essential oil of Artemisia lerchiana Web. plants growing in Volgograd oblast was studied. Sampling was performed from plots contrasting in climatic and soil characteristics.
Essential oil was obtained by hydrodistillation. The content of essential oil in shoot biomass increased gradually during
shoot formation, flower bud formation, and flowering beginning and then decreased. The highest content of essential oil varied
from 1.1 to 1.5% of plant dry weight at the stage of flower bud formation. More than thirty compounds were identified by gas
chromatography-mass spectrometry. The following major components were found: camphor, borneol, bornylacetate, camphene, and
1,8-cineole. Some of compounds (sesquiterpenes and sesquiterpenoids) were identified for the first time. The time-course of
accumulation of essential oil components strongly depended on habitat edaphic factors and climatic conditions during the year
of sampling. The results permit a conclusion that A. lerchiana is a valuable producer of essential oils.
Original Russian Text ? E.B. Kirichenko, Yu.V. Orlova, D.V. Kurilov, 2008, published in Fiziologiya Rastenii, 2008, Vol. 55,
No. 6, pp. 934–941. 相似文献
12.
Tatina T. Todorova Ventsislava Y. Petrova Stéphane Vuilleumier Anna V. Kujumdzieva 《Archives of microbiology》2009,191(11):837-845
Growth of Saccharomyces cerevisiae
ure2Δ mutant strain was investigated in the presence of diverse oxidant compounds. The inability of the strain to grow on a medium
supplemented with H2O2 was confirmed and a relationship between diminishing levels of glutathione (GSH) and peroxide sensitivity was established.
Data for the lack of significant effect of URE2 disruption on the cellular growth in the presence of paraquat and menadione were obtained. The possible role of Ure2p in
acquiring sensitivity to oxidative stress by means of its regulatory role in the GATA signal transduction pathway was discussed.
It was suggested that the susceptibility of ure2Δ mutant to the exogenous hydrogen peroxide can result from increased GSH degradation due to the deregulated localization of
the γ-glutamyl transpeptidase activating factors Gln3/Gat1. The important role of Ure2p in in vivo glutathione-mediated reactive
oxygen species (ROS) scavenging was shown by measuring the activity of antioxidant enzymes glutathione peroxidase, superoxide
dismutase (SOD) and catalase in an URE2 disrupted strain. A time-dependent increase in SOD and catalase activity was observed. More importantly, it was shown that
the ure2 mutation could cause significant disturbance in cellular oxidant balance and increased ROS level. 相似文献
13.
Optimization of conditions for hydroquinone biotransformation into its β-d-glucoside, arbutin, in agitated shoot cultures of Ruta graveolens L. and Hypericum perforatum L. allowed us to obtain a maximum content of this important therapeutic and cosmetic product of 7.8 and 7.2% (dry weight),
respectively. These contents are higher than respective values required for standardization of known arbutin-containing plant
raw materials according to the European Pharmacopoeia and national pharmacopoeias of European countries. 相似文献
14.
Quantitative trait loci (QTL) detection was carried out for adventitious rooting and associated propagation traits in a second-generation
outbred Corymbia torelliana × Corymbia citriodora subspecies variegata hybrid family (n = 186). The parental species of this cross are divergent in their capacity to develop roots adventitiously on stem cuttings
and their propensity to form lignotubers. For the ten traits studied, there was one or two QTL detected, with some QTL explaining
large amounts of phenotypic variation (e.g. 66% for one QTL for percentage rooting), suggesting that major effects influence
rooting in this cross. Collocation of QTL for many strongly genetically correlated rooting traits to a single region on linkage
group 12 suggested pleiotropy. A three locus model was most parsimonious for linkage group 12, however, as differences in
QTL position and lower genetic correlations suggested separate loci for each of the traits of shoot production and root initiation.
Species differences were thought to be the major source of phenotypic variation for some rooting rate and root quality traits
because of the major QTL effects and up to 59-fold larger homospecific deviations (attributed to species differences) relative
to heterospecific deviations (attributed to standing variation within species) evident at some QTL for these traits. A large
homospecific/heterospecific ratio at major QTL suggested that the gene action evident in one cross may be indicative of gene
action more broadly in hybrids between these species for some traits. 相似文献
15.
Gerardo Armando Aguado-Santacruz Quintín Rascón-Cruz Blanca Moreno-Gómez Ramón Gerardo Guevara-González Lorenzo Guevara-Olvera Juan Francisco Jiménez-Bremont Sigifredo Arévalo-Gallegos Edmundo García-Moya 《In vitro cellular & developmental biology. Plant》2009,45(6):681-692
Until recently, information about the effects of transforming plants with the rolA gene of Agrobacterium rhizogenes has been restricted mainly to dicots in which a severely wrinkled phenotype, reduced internode distances, and abnormal reproductive
development were commonly observed. In this work, we analyzed the effects associated with the expression of this gene in a
new genetic context: the forage grass genome. Transgenic P35S•rolA plants of blue grama grass (Bouteloua gracilis) were obtained by a biolistic approach employing embryogenic chlorophyllic cells as the target material. Four independent
transgenic lines with regeneration capacity were recovered, which showed stable integration of this transgene as demonstrated
by polymerase chain reaction and Southern blot hybridization. Growth of the rolA-transformed lines under greenhouse conditions provided evidence for a new biotechnological application for the rolA gene in plants, namely, the improvement of biomass production in forage grasses. Additionally, we described here a new phenotypic
marker (referred to here as the “hairy embryo” syndrome) that can be instrumental for the early identification of transformation
events when transforming grasses with this gene. 相似文献
16.
Our study focuses on the ground vegetation dynamics and its dependence on microsite conditions in declined climax mountain
Norway spruce forests during the recovery period (1995–2006) following upon the considerable decrease of SO2 pollution. We showed that ground vegetation development shifted from prevailing mosses and vegetation-free sites covered
with spruce litter to dominance by Avenella flexuosa during the earlier period of massive decline of the observed ecosystems. The expansion of Vaccinium myrtillus seems to occur mainly under the gradually defoliating tree crowns whereas larger canopy gaps and quickly deforested areas
are more successfully colonized by grasses, especially Calamagrostis villosa. The gradual spruce stand decline, as well as the corresponding ground vegetation dynamics, proceeded until the end of the
twentieth century. Afterwards, the ground vegetation responded to the interruption of trees dying and stopped its expansion
on spruce litter microsites. Retreat of both dominant grasses accompanied by the remarkable increase in cover of mosses occurred. 相似文献
17.
The wolf spider Pardosa cribata Simon is the most abundant ground-dwelling spider inhabiting citrus orchards in eastern Spain. However, little is known about
its activity-density and its predatory role in the citrus agrosystem. Here we report on the activity-density of P. cribata monitored by pitfall traps, and on its capacity to prey on two citrus pests that appear both in the citrus canopy and the
ground cover, Ceratitis capitata (Wiedemman) and Myzus persicae (Sulzer), respectively. Pardosa cribata was present in citrus orchards throughout the year, with a peak in spring and a higher peak in summer. Pardosa cribata preyed on adults and third-instar larvae but not on pupae of C. capitata. A type II functional response was obtained for teneral-like adults, with an estimated attack rate (a′) of 0.771 ± 0.213 days−1 and a handling time (T
h) of 0.051 ± 0.013 days. Pardosa cribata also preyed efficiently on M. persicae, giving a type II functional response with an estimated attack rate and handling time of 2.833 ± 0.578 days−1 and 0.031 ± 0.001 days, respectively. The data reported here indicate that this wolf spider could play an important role
in regulating both these pests, and therefore might contribute to developing conservation biological control strategies for
citrus pests.
Handling Editor: Arne Jenssen. 相似文献
18.
Leandro Kanamaru Franco de Lima Elisa Helena Giglio Ponsano Marcos Franke Pinto 《World journal of microbiology & biotechnology》2011,27(11):2553-2558
One application of biotechnology that contributes to sustainable development is the utilization of industrial byproducts as
substrates for the production of substances of interest by microorganism. In this work, liquid effluent from tilapia fish
processing was used as a substrate for the growth of Rubrivivax gelatinosus with the aim of studying the bacterial photo heterotrophic metabolism. Cultivation conditions included 32 ± 2°C, 1,400 ± 200
lux and 7 days. In the initial days, the best cell mass production (0.273 g l−1 with 72 h), specific growth rate (0.188 h−1 with 48 h) and chemical oxygen demand (COD) decrease (43% with 72 h) were reached. Typical bacterial oxycarotenoids were
identified after 3 days of cultivation, averaging 3.03 mg g−1 biomass. Bacterial growth in the effluent during the period of study resulted in pH increase to 7.9, total nitrogen, oils
and greases and COD decreases of 22.46, 47.71 and 52%, respectively, and dry cell mass production of 0.18 g l−1. The bacterial growth in the wastewater provided biomass and oxycarotenoids and the removal of pollutant load. 相似文献
19.
There are three most important bacterial causative agents of serious infections that could be misused for warfare purposes:
Bacillus anthracis (the causative agent of anthrax) is the most frequently mentioned one; however, Fracisella tularensis (causing tularemia) and Yersinia pestis (the causative agent of plague) are further bacterial agents enlisted by Centers for Disease Control and Prevention into the category A of potential biological weapons. This review intends to summarize basic information about these bacterial
agents. Military aspects of their pathogenesis and the detection techniques suitable for field use are discussed. 相似文献
20.
The disappearance of low-intensity types of agricultural land use such as mowing and grazing is a global phenomenon which
leads to changes in species composition and interactions in plant communities. In central Germany, formerly species-rich,
semi-natural dry grasslands have been converted into species-poor communities dominated by Festuca rupicola or Poa angustifolia. As a consequence, several forbs have become endangered, and biodiversity has decreased. In a 5-year competition experiment
(replacement design; pots were placed outdoors at Halle Botanical Garden), we evaluated the performance of plant–plant interactions
between the rare forb Campanula glomerata, F. rupicola and P. angustifolia, respectively. The response of C. glomerata to the presence of the two grass species were measured by stem length, number of flowers and above-ground biomass annually
harvested. We did not find significant differences in C. glomerata stem lengths between years and treatments, but flower production, which was highest in the first year, strongly decreased
in the subsequent years. Moreover, flower production was lower in combination with P. angustifolia than with F. rupicola. Biomass production showed significant differences between years, but not between treatments. The positive and negative interactions
between C. glomerata and the two grass species was estimated by calculating Relative Neighbour Effect Index (RNE). In combination with F. rupicola, interactions switched between facilitation and competition from year to year. In the presence of P. angustifolia, competitive effects on C. glomerata were highest in the second year, but declined from year to year. Curiously, there were no significant correlations between
positive and negative interactions with climatic conditions (annual temperature, precipitation and relative air humidity).
Our results showed that the response of the rare forb C. glomerata varies with neighbour species, and that fecundity is more prominently affected by competition than stem height or biomass.
Our data indicate that biomass removal by traditional land use methods would facilitate the restoration of species-rich dry
grassland communities. 相似文献