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1.
Temporary pools are numerous in coastal plains of Atlantic Morocco and have a rich and diverse flora. These habitats are increasingly
under pressure by man impact through grazing by domestic livestock and the development of annual crops in their catchments.
The objectives of this work were to evaluate the species richness and the species composition of the vegetation of a sample
of 30 pools in this region, in order to assess the structure of the vegetation within pools and to evaluate the role of environmental
and anthropogenic factors in their richness and species composition. The results highlighted the species richness of the pools
with 300 species found among which annual species were heavily dominant. The structure of the vegetation varied within pools
according to a topographical/flooding gradient and between pools in relation with the land use in the surrounding areas. Three
vegetation belts were recognized from the centre to the periphery of the pool. The total species richness per pool was not
found significantly related to environmental or anthropogenic factors. The species characteristics of the pools were found
mostly in the centre and their number affected by hydrological factors and land use in the pool and in the surrounding areas.
The species characteristics of woodland habitats and of agriculture crops were found mostly in the peripheral zone. Temporary
pools maintain specific communities of both aquatic and amphibious species, probably because of the selection induced by water
level variations. The peripheral zone, although often dominated by terrestrial species, is clearly interpreted as part of
the pool. It contains amphibious species highly characteristic of the pool for which the irregular flooding is a key environmental
factor which decreases competition. 相似文献
2.
Janne Alahuhta Sarian Kosten Munemitsu Akasaka Dominique Auderset Mattia M. Azzella Rossano Bolpagni Claudia P. Bove Patricia A. Chambers Eglantine Chappuis John Clayton Mary de Winton Frauke Ecke Esperança Gacia Gana Gecheva Patrick Grillas Jennifer Hauxwell Seppo Hellsten Jan Hjort Mark V. Hoyer Christiane Ilg Agnieszka Kolada Minna Kuoppala Torben Lauridsen En Hua Li Balázs A. Lukács Marit Mjelde Alison Mikulyuk Roger P. Mormul Jun Nishihiro Beat Oertli Laila Rhazi Mouhssine Rhazi Laura Sass Christine Schranz Martin Søndergaard Takashi Yamanouchi Qing Yu Haijun Wang Nigel Willby Xiao Ke Zhang Jani Heino 《Journal of Biogeography》2017,44(8):1758-1769
3.
Catharanthus roseus cell suspension cultures may accumulate large quantities of malate in the vacuolar space. Upon transfer into a fresh medium malate moves out of the vacuole. This compound is then oxidized and its assimilatory products (CO2 + HCO3?) are excreted into the medium. The malate concentration decreases concurrently with an intracellular accumulation of nitrate. The opposite time course changes in malate and nitrate concentrations can be slowed down by treatment with synthetic auxins and fusicoccin which increase the HCO3? concentration in the cytoplasm. A line of evidence is presented which shows that malate consumption is causally related with the uptake of nitrate. The involvement of a HCO3?/NO3? antiport is proposed. 相似文献
4.
A composite photoresist has been developed for the direct photopatterning of electrodes useful as biochip substrates. The material is composed of SU-8 polymer added with graphite carbon filler which enables patterning of conductive thin films (22μm) on both glass substrate and transparency flexible film with a standard UV photolithography protocol. The resolution obtained using the conductive composite compared well with the bare resist, with lateral resolutions of 5 and 10μm for bare and conductive resists, respectively. The obtained electrodes, after an electrochemical pre-treatment, exhibited very good electrochemical behaviors, opening the path to various electrochemical detections and grafting possibilities. In order to demonstrate the potentialities of the developed material in the biosensors and biochips field, DNA probes were electrografted, using diazonium chemistry, directly at the composite photoresist surface. Target oligonucleotide interactions were detected using chemiluminescent labeling and a satisfactory detection limit of 0.25nM target sequence was demonstrated with a detection ranging over three orders of magnitude. 相似文献
5.
Koufan Meriyem Mazri Mouaad Amine Essatte Amine Moussafir Sanae Belkoura Ilham El Rhaffari Lhoussaine Toufik Ibrahim 《Plant Cell, Tissue and Organ Culture》2020,140(2):369-378
Plant Cell, Tissue and Organ Culture (PCTOC) - European mistletoe (Viscum album) is a medicinal plant with significant anticancer properties. In vitro callus production provides an essential... 相似文献
6.
Koufan Meriyem Belkoura Ilham Mazri Mouaad Amine Amarraque Abderrahim Essatte Amine Elhorri Hafsa Zaddoug Fatima Alaoui Tajlmolk 《Plant Cell, Tissue and Organ Culture》2020,141(1):217-227
Plant Cell, Tissue and Organ Culture (PCTOC) - Argan (Argania spinosa (L.) Skeels) is an endangered and endemic agroforestry species of Morocco highly appreciated for its nutraceutical properties.... 相似文献
7.
Physical soil disturbance and the hydrology of temporary pools affect the biomass, species composition and richness of plant
communities. Disturbance liberates sites for the random recruitment of new individuals. The addition of seeds modifies the
structure of the communities. In order to verify these hypotheses concerning the vegetation of temporary pools, an experiment
was carried out using 72 soil samples collected from a pool in Western Morocco and placed in containers. Three types of laboratory
treatments were applied, each combined with control treatments: soil disturbance (control/disturbed), hydrology (flooded,
saturated and dry) and seed addition (sowing/no sowing). The total biomass, the annual and perennial species richness were
calculated for each sample to test the effects of disturbance, hydrology and seed addition on the biomass and species richness
of the various plant communities. The results show that disturbance reduces the total biomass, especially of perennials, but
without significantly increasing the richness of annuals. Seed addition does not affect the total biomass and reduces total
richness only in saturated soil, where biomass production is high. The most extreme stress conditions (drought and flooding)
limit the abundance of species and therefore competition.
Guest editors: B. Oertli, R. Cereghino, A. Hull & R. Miracle
Pond Conservation: From Science to Practice. 3rd Conference of the European Pond Conservation Network, Valencia, Spain, 14–16
May 2008 相似文献
8.
Effects of light and temperature, on the growth of three freshwater green algae isolated from an eutrophic lake and identified as Selenastrum minutum, Coelastrum microporum f. astroidea and Cosmarium subprotumidumwere studied in batch cultures under non-nutrient limited conditions. Experiments were performed to determine the growth rate over a wide range of light intensities (30–456 mol m–2 s–1) and temperature (15–35°C), using a 15/9 (light/dark) photoperiod cycle. The maximum growth rates and the optimum light intensities at a temperature of 35°C were 1.73 d–1 and 420 mol m–2 s–1for Selenastrum minutum, 1.64 d–1 and 400 mol m–2 s–1 for Coelastrum microporum and 1.00 d–1 and 400 mol m–2 s1 for Cosmarium subprotumidum. The results were fitted with the mathematical models of Steele (1965), Platt & Jassby (1976) and Peeters & Eilers (1978). Steele's function and equation of Platt & Jassby don't describe correctly the relationship between the growth and light intensity. In the opposite, the equation of Peeters & Eilers provides the best fit for the three species. 相似文献
9.
The secondary active, Na+ coupled glycine betaine carrier BetP from Corynebacterium glutamicum BetP was shown to harbor two different functions, transport catalysis (betaine uptake) and stimulus sensing, as well as activity regulation in response to hyperosmotic stress. By analysis in a reconstituted system, the rise in the cytoplasmic K+ concentration was identified as a primary stimulus for BetP activation. We have now studied regulation of BetP in vivo by independent variation of both the cytoplasmic K+ concentration and the transmembrane osmotic gradient. The rise in internal K+ was found to be necessary but not sufficient for BetP activation in cells. In addition hyperosmotic stress is required for full transport activity in cells, but not in proteoliposomes. This second stimulus of BetP could be mimicked in cells by the addition of the amphiphile tetracaine which hints to a relationship of this type of stimulus to a change in membrane properties. Determination of the molecular activity of BetP in both cells and proteoliposomes provided experimental evidence that in proteoliposomes BetP exists in a pre-stimulated condition and reaches full activity already in response to the K+ stimulus. 相似文献
10.
La?la Rhazi Patrick Grillas Er-Riyahi Saber Mouhssine Rhazi Luc Brendonck Aline Waterkeyn 《Hydrobiologia》2012,689(1):23-36
Although Mediterranean temporary pools are of great value for conservation, they are in rapid decline under the impact of
various forms of anthropogenic pressure. Their disappearance from the landscape may result in a weakening of the biological
connections between pools due to increasing isolation and the impoverishment of their communities. In Western Morocco (province
of Benslimane), temporary pools have undergone severe regression over the past decades. The quantification of these losses
and the impact on the richness of plant communities remain, however, unstudied. Since this is of vital importance for the
conservation of the biodiversity of these habitats, a study has been undertaken associating (1) an assessment of the pool
losses (both in density and surface area) between 1955 and 2001 using remote sensing, (2) surveys of vegetation and water
depth (in 2006) in 48 pools, and (3) an assessment of the density and surface area of pools occurring within a 3 km radius
around each of the sampled pools. The results show a loss of 23% in number and 61% in surface area of pools in the province
over a period of 47 years. This decline, promoted by their small size and shallowness, is probably related to socio-economic
changes (intensification of agricultural practices and population growth). The richness in characteristic and rare species
of the pools was related to both local (water depth) and regional features (land use, pool density and total water surface
area in the surrounding landscape). The significant impact of the current density of pools and their total surface area on
the conservation value of the studied pools suggests a weakening of the metacommunity dynamics between pools. Given the rapid
socio-economic changes in the province and the current rate of pool disappearance (0.5% per year) we predict a continuing
reduction in pool density with a high risk of the widespread loss of their unique flora in the long term. 相似文献