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1.
We investigated the ecophysiology (physiological ecology) of plant succession within a coastal wetland community. The photosynthetic characteristics of six plants were studied; Scirpus mariqueter and Carex scabrifolia in early successional communities, Phragmites communis and Tamarix chinensis in mid successional communities, and Salix matsudana and Imperata cylindrica in later successional communities. Environmental factors were concurrently determined for each community. Relationships between photosynthetic and environmental factors were analyzed by path analysis, and the dependence of photosynthesis on particular environmental factors was shown to vary between plants in the differing successional communities. Ability to cope with irradiation appears to be one of the most important factors influencing plant succession. The increasing stratification of plant communities following colonization of new coastal land necessitates differing physiological strategies and photosynthetic dynamics in the later colonizing plants.  相似文献   

2.
The impact of long-term seasonal soil freezing, drought, and waterlogging on the rhizosphere of young Scots pine trees (Pinus sylvestris L., age class 1) has been simulated in experiments. The results have shown that cold stress exposure leads to reduction of the rates of linear and radial tree growth and of chlorophyll content in needles, a shift in the peak of starch content, and initiation of free amino acid deposition in the aboveground plant parts. Drought activates utilization of carbohydrate reserves and amino acid accumulation in the root bast, whereas soil waterlogging stimulates deposition of carbohydrates but causes a decrease in the levels of chlorophyll and amino acids in all plant tissues.  相似文献   

3.

Vegetation indices are calculated from reflectance data of discrete spectral bands. The reflectance signal in the visible spectral range is dominated by the optical properties of photosynthetic pigments in plant leaves. Numerous spectral indices have been proposed for the estimation of leaf pigment contents, but the efficacy of different indices for prediction of pigment content and composition for species-rich communities is unknown. Assessing the ability of different vegetation indices to predict leaf pigment content we identify the most suitable spectral indices from an experimental dataset consisting of field-grown high light exposed leaves of 33 angiosperm species collected in two sites in Mallorca (Spain) with contrasting leaf anatomy and pigment composition. Leaf-level reflectance spectra were recorded over the wavelength range of 400 – 900 nm and contents of chlorophyll a, chlorophyll b, total carotenoids, and anthocyanins were measured in 33 species from different plant functional types, covering a wide range of leaf structures and pigment content, five-fold to more than 10-fold for different traits. The best spectral region for estimation of leaf total chlorophyll content with least interference from carotenoids and anthocyanins was the beginning of near-infrared plateau well beyond 700 nm. Leaves of parallel-veined monocots and pinnate-veined dicots had different relationships between vegetation indices and pigments. We suggest that the nature and role of “far-red” chlorophylls which absorb light at longer wavelengths than 700 nm constitute a promising target for future remote sensing studies.

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4.
A comparative analysis of several morphological, physiological, and biochemical characteristics of leaves has been performed in birch (Betula pendula Roth), linden (Tilia cordata Mill.), and poplar (Populus nigra L.) trees growing in industrial areas of Yaroslavl with different levels of anthropogenic pollution. The results show that high concentrations of pollutants in the atmosphere suppress the growth of leaves, and the number and severity of necrotic lesions in them increase. Water content in leaves becomes lower, whereas ash content increases. The contents of photosynthetic pigments change as well: the leaves contain smaller amounts of chlorophylls a and b, whereas the accumulation of carotenoids increases. Judging from changes in the test parameters, P. nigra is more resistant to pollution than B. pendula and T. nordata.  相似文献   

5.
Environmental factors like temperature and soil humidity are recognized as influencing factors on photosynthetic response and organic productivity, distribution and biochemical characteristics of plants. Here we present measurements of gas exchange parameters, water-use efficiency (WUE) and nitrogen-use efficiency (NUE) of field-grown invasive species Ambrosia artemisiifolia L., Ambrosia trifida L. and Iva xanthifolia Nutt., in order to define their potentials as colonizers. Biogenic volatile organic compounds (BVOC) in leaves and flowers depending on soil humidity were also investigated.  相似文献   

6.
A site that covers over 20 acres of coastal saline depression in the western Mediterranean coastal desert of Egypt (El-Hammra station, the main crude oil pipeline terminal in Al-Alamein) is contaminated with crude oil spill as a result of activities from refineries, oilfield blowouts, tanker and pipeline break-ups. This area, prior to contamination, was dominated by different common halophytes. However, Limoniastrum monopetalum is now the only species found growing in the oil-contaminated soil. A specific question addressed in the present study was: what are the biochemical changes occurring in a desert plant growing in oil-contaminated soils? Major metabolites such as proline, betaine, free amino acids, fatty acid esters and mineral elements were studied. The plant samples were collected from the oil-contaminated, as well as noncontaminated, sites. The higher concentration in the selected organic metabolites in the plants growing in the contaminated site compared to those in noncontaminated site may be due to differences in a number of receptors. The sensitivity of such receptors for the environmental signal that cause differences in genetic expression leads to differences in physiological processes. The change in the landscape of the contaminated area and the elimination of the natural vegetation, except L. monopetalum, may explain the competitive balance toward the oil-resistant species.  相似文献   

7.
A revegetation trial was conducted to evaluate the feasibility of growing a legume species, Prosopis juliflora L., on fly ash ameliorated with combination of various organic amendments, blue-green algal biofertilizer and Rhizobium inoculation. Significant enhancements in plant biomass, photosynthetic pigments, protein content and in vivo nitrate reductase activity were found in the plants grown on ameliorated fly ash in comparison to the plants growing in unamended fly ash or garden soil. Higher growth was obtained in fly ash amended with blue-green algae (BGA) than farmyard manure or press mud (PM), a waste from sugar-processing industry, due to the greater contribution of plant nutrients, supply of fixed nitrogen and increased availability of phosphorus. Nodulation was suppressed in different amendments of fly ash with soil in a concentration-duration-dependent manner, but not with other amendments. Plants accumulated higher amounts of Fe, Mn, Cu, Zn and Cr in various fly ash amendments than in garden soil. Further, inoculation of the plant with a fly ash tolerant Rhizobium strain conferred tolerance for the plant to grow under fly ash stress conditions with more translocation of metals to the above ground parts. The results showed the potential of P. juliflora to grow in plantations on fly ash landfills and to reduce the metal contents of fly ash by bioaccumulation in its tissues.  相似文献   

8.
The amino acid spectrum of blood plasma in three bat species (Myotis dasycneme, Pipistrellus nathusii, Vespertilio murinus) inhabiting the Urals has been studied for the first time. The bats were trapped in the zone of their high abundance in Chelyabinsk oblast (2013–2014). Free amino acids were determined by liquid ion exchange chromatography (a total of 384 determinations). It has been shown that the plasma amino acid spectrum consists of 22 amino acids in subadult bats of all three species, but there are species-specific differences in their concentrations. The total amino-acid pool concentration in migratory P. nathusii and V. murinus exceeds that in resident M. dasycneme by factors of 2.9 and 1.8, respectively. Migratory species are characterized by a high concentration of plasma arginine: it is six times higher in V. murinus than in M. dasycneme, and in P. nathusii arginine accounts for 25.4% of the amino acid pool. The group of glucogenic amino acids is prevalent in the blood plasma of migratory species (75% in V. murinus and 79% in P. nathusii), while in M. dasycneme the total proportion of lysine, glycine, and glutamic acid is 2.3 times lower than in P. nathusii and 1.7 lower than in V. murinus (p < 0.05). These results provide evidence for significant differences in the contents of free blood plasma amino acids between migratory and resident bat species.  相似文献   

9.
Karanja oil methyl ester (KOME), a biodiesel prepared from Karanja oil, a potential source of non-edible oil in India and a prospective alternative to the diesel fuel, shows comparable performance and considerable reduction in emissions except NOx. Exhaust gas recirculation (EGR) is a popular method of reducing the NOx emission. The aim of this experimental work was to study the potential of the cooled EGR in a direct injection compression ignition engine operating with the KOME and its blend. The study was conducted with the different EGR rates. Performance and emission parameters were compared by using diesel, KOME and its blend employing EGR and with the same fuels without EGR. The study also differentiates the effect of EGR on KOME and its blend with the neat diesel. The effect of EGR was found to be slightly higher for KOME biodiesel and its blend than for neat diesel. Increased NOx emission using KOME biodiesel was also found to be reduced by using EGR.  相似文献   

10.
Changes in the contents of anthocyanins, ascorbic acid, and riboflavin were studied in plants growing under pollution with petroleum products along railroad tracks (Geum urbanum L., Anthriscus sylvestris L., Glecoma hederata L., Taraxacum officinalisL., Dactylis glomerata L., and Achillea millefolium L.) and in seedlings grown in soil containing 5–10% crude oil (Hordeum vulgare L., D. glomerata, Vicia sativa L., Panicum miliaceum L., and Zea mays L.). In the former case, the plants accumulated ascorbic acid and anthocyanins (on average, 2 and 5.2 times those in the norm, respectively), and riboflavin (in both reduced and oxidized forms). In the latter case oil-induced stress also proved to stimulate the accumulation of all test substances in the seedlings. The content of anthocyanins is proposed as a test parameter reflecting the degree of environmental pollution, which may be useful for prompt bioindication of pollutants in the ecological monitoring of plant communities.  相似文献   

11.
To estimate the response of conifers to long-term industrial air pollution at the pigment system level, the dynamics of photosynthetic pigments have been studied in needles of Scots pine (Pinus sylvestris L.) and Siberian spruce (Picea obovata Ledeb.) growing at different distances from the emission source (a pulp and paper mill). It has been shown that the pigment apparatus of spruce. The results show that in spruce, unlike in pine, the pigment apparatus remains unchanged under the effect of weak pollution. Long-term exposure at high levels of industrial emission results in suppression of chlorophyll and carotenoid syntheses in pine but stimulates pigment production in spruce. An increase in the contents of pigments in the needles of conifers growing in the impact zone of the pulp and paper mill reflects a compensatory mechanism of adaptation of their pigment system to long-term stress exposure.  相似文献   

12.
The possibility of symbiotic, mutualistic (++) interrelations between epibiontic microalgae (Characidiopsis ellipsoidea, Colacium vesiculosum) and cyclopoids (Cyclops vicinus, Mesocyclops leukarti) in the Bugach recreational reservoir with a bloom of cyanobacteria is demonstrated. Overgrown cyclopoids, compared to those free from microalgae, have advantages in oxygen supply, which may be insufficient in the period of intensive algal bloom. Calculations have shown that oxygen requirements of cyclopoids may be fully satisfied due to C. vesiculosum photosynthetic activity in the dysphotic zone if the density of overgrowth exceeds 1000 algal cells per individual. There is no significant correlation between the natural mortality of crustaceans and the indices of their overgrowth by microalgae.  相似文献   

13.
Parameters regarding fate of 63Ni in the soil–plant system (soil: solution distribution coefficient, Kd and soil plant concentration ratio, CR) are mostly determined in controlled pot experiments or from simple models involving a limited set of soil parameters. However, as migration of pollutants in soil is strongly linked to the water migration, variation of soil structure in the field and seasonal variation of evapotranspiration will affect these two parameters. The aim of this work was to explore to what extent the downward transfer of 63Ni and its uptake by plants from surface-contaminated undisturbed soil cores under cultivation can be explained by isotopic dilution of this radionuclide in the pool of stable Ni of soils. Undisturbed soil cores (50 cm × 50 cm) were sampled from a brown rendzina (Rendzic Leptosol), a colluvial brown soil (Fluvic Cambisol) and an acidic brown soil (Dystric Cambisol) using PVC lysimeter tubes (three lysimeters sampled per soil type). Each core was equipped with a leachate collector. Cores were placed in a greenhouse and maize (DEA, Pioneer®) was sown. After 44 days, an irrigation was simulated at the core surfaces to supply 10 000 Bq 63NiCl2. Maize was harvested 135 days after 63Ni input and radioactivity determined in both vegetal and water samples. Effective uptake of 63Ni by maize was calculated for leaves and kernels. Water drainage and leaching of 63Ni were monitored over the course of the experiment. Values of Kd in surface soil samples were calculated from measured parameters of isotopic exchange kinetics. Results confirmed that 63Ni was strongly retained at the soil surface. Prediction of the 63Ni downward transfer could not be reliably assessed using the Kd values, since the soil structure, which controls local water fluxes, also affected both water and Ni transport. In terms of 63Ni plant uptake, the effective uptake in undisturbed soil cores is controlled by isotope dilution as previously shown at the pot experiment scale.  相似文献   

14.
Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously.  相似文献   

15.
Leaf samples of six plant species collected from locations near the Al-fabrication plants in Sai Kung, Hong Kong were found to be heavily contaminated by Al, Cd, Pb, Ni, Cu and Zn, as determined by inductively — coupled plasma emission spectrophotometer (ICP). Studies using scanning electron microscope incorporated with X-ray microanalyzer showed that significant amounts of dust, with elevated concentrations of heavy metals, were deposited on the leaf surface. The stomatal pores were partially plugged and the guard cells were distorted. The amount of dust deposition and metal contamination varied significantly among different species. Lantana camara had the highest concentrations of all metals. Washing with deionized water could remove the surficial dust particles and reduce the metal contamination, with a degree of effectiveness depending on plant species and metal species. About 50% of Al and other metals were removed from leaves of L. camara and Fiscus variegata by washing, whereas only 20% removal was recorded in Bauhina variegata, the species had the least dust deposition. The soil samples and Al wastes collected from the same sites also exhibited higher values of total metal concentrations than the control. However, the contents of extractable metals were extremely low and were almost below the limits of detection. Experimental data further suggested that the source of leaf metals was mainly accumulated from metal-enriched aerosols, either from Al-fabrication plants or from automobile exhausts, and contribution from soil was relatively unimportant.  相似文献   

16.
This survey was done to register information of cerrado's medicinal plants sellers, who trade in downtown Anápolis (Brazil). The information obtained was pertaining to medicinal purposes, the most used portion of the plants, ecological lore and the best selling plants. A cluster analysis was performed to group the plants by medicinal use and by their chemical composition, obtained in the current literature. To verify if differences in chemical compounds correspond to differences in medicinal use, a Mantel test was applied to assess the correlation in those grouping. The results showed a low but significant correlation between medicinal use and chemical composition of the plants, nevertheless, there is still little published information on the pharmacological potential of cerrado's plant. Trade of cerrado's medicinal plants has local economic importance for a low income and illiterate population and the urbanization of the activity caused the loss of some traditional knowledge, like ecological information about the plants. A traveling salesman of medicinal plants (raizeiro) seems to have the most traditional lore, but he was not found to the interview. The excessive use of roots for medicinal purposes can be a threat to cerrado biome coupled with other human pressures in this ecosystem. Traditional knowledge of medicinal plants is endangered as much as the ecosystem that originated it.  相似文献   

17.
ABSTRACT

Poultry skin waste is considered to be a promising source of biodiesel. However, this source presents an environmental threat as it is being discharged into landfills without any treatment. We studied the feasibility of biodiesel production from poultry skin waste. Two-step extraction of lipids from chicken’s skin was developed and gave 97.5% yield using the optimum time and temperature. Esterification was then optimised to remove free fatty acids (FFA) where the ideal parameters were 65 °C during 30min with a molar ratio of methanol to oil of (1:3) and 1% of H2SO4. The third step was the transesterification which was performed using 60 °C and 300–600 rpm agitation for 1 h, with 1% basic catalyst and 1:3 (molar ratio) of methanol to oil. The biodiesel (FAME), was characterised using gas chromatography coupled with mass spectrometry (GC-MS) followed by chemical and physical analyses such as iodine number, acid number, flash point and cetane number. The total conversion was obtained using above conditions and most of the studied proprieties of produced biodiesel meet the EN14214 standard. This is an extremely encouraging result, offering a good source of biodiesel by valuing poultry skin waste.  相似文献   

18.
Topical connections between F. aquilonia ants and herbaceous plants in a fragmented forest area have been analyzed. The species composition of the group of herbaceous plants changing their occurrence frequency in response to the presence of F. aquilonia nests has been determined. Ecological and phytocenotic parameters of herbaceous plants contributing to the development of the myrmecotopic assemblage are described. Signs of meadowfication and synanthropization of the herbaceous layer around ant nests have been observed.  相似文献   

19.
Turions of Potamogeton crispus were planted in several turbid waters. Some parameters of growth, reproduction and chlorophyll fluorescence were measured. The results were as follows: (1) Sprouting rates in all groups reached to 100.0% on the 17th day. (2) The parameters of the growth (stem and leaf) and chlorophyll fluorescence (ΦPSII, qP and qN) in 120 and 150NTU waters were inhibited heavily 60 days later, and their survival time was only 140 days. However, the plants in 30 to 90NTU waters could grow near water surface, their survival time was about 190 days. (3) After 150 days, the saturating irradiance intensity and rETRmax of the leaves in 30 to 90NTU waters markedly decreased with an increase in the amount of attached silts, and the number and fresh mass of turions (propagula) in 60 and 90NTU waters were significantly lower than the control. In summary, P. crispus in 0.7-metre-deep turbid water with suspended silts (not more than 90NTU) could sprout and grow normally, and produce the turions.  相似文献   

20.
A comparative cytogenetic study has been performed in four populations of two pine species, Pinus cretaceae Kalen. and P. sylvestris L., growing on sandy and chalky substrates in Voronezh and Belgorod oblasts. Significant differences in the parameters of mitotic and nucleolar activities, as well as the rate and spectrum of mitotic pathology, between populations of P. cretaceae and P. sylvestris and between populations of P. cretaceae growing under different conditions have been found. Populations of P. sylvestris growing on sandy and chalky substrates differ from each other in nucleolar activity. These differences may be adaptive and reflect the characteristic metabolic patterns and biological plasticity of pines growing under specific conditions.  相似文献   

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