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ABSTRACT: A pot culture experiment was carried out to study the effects of land use history and inoculation with Fusarium oxysporum f. sp. cucumberinum Owen (Foc) on soil nematodes communities during the cucumber growing season in 2007. The results showed that land use history and inoculation
had significant effects on the abundance and diversity of soil nematodes. Bacterivores were found to be the most dominant
group in this study. Irrespective of inoculation, numbers of fungivores, plant-parasites and values of trophic diversity index
(TD) and plant-parasites index (PPI) were greater in greenhouse soils (GH) than in open field vegetable soils (OF) during
the growth period of cucumber. While, the number of omnivores-predators and values of richness (SR) and maturity index (MI)
presented an opposite trend. Foc inoculation had noticeable effects on numbers of plant-parasites and some taxa, such as Helicotylenchus, Epidorlaimus at flowering stage and Aphelenchus, Tobrilus at fruiting stage. Besides, inoculation significantly affected values of PPI at flowering stage and TD at fruiting stage,
respectively. The faunal analysis showed that soil food web in GH was highly disturbed and in OF was degraded.
Helminthologia 04/2012; 45(4):204-210. · 0.77 Impact Factor
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ABSTRACT: Polycyclic aromatic hydrocarbons (PAHs) commonly found in soils can be degraded in rhizosphere, but may also be taken up by plants. The effects of arbuscular mycorrhizal (AM) fungi on uptake of phenanthrene (PHE) and pyrene (PYR) in maize and on their dissipation in soil were investigated using the three-compartmentalized rhizoboxes. Inoculation of Glomus mosseae significantly (p<0.01) increased PHE and PYR concentrations in maize roots and significantly (p<0.05) enhanced PYR translocation from roots to stems in the soil treatments of the PHE+PYR spiked-soils added into the central compartment of the rhizoboxes. There was a significant (p<0.05) dissipation gradient of PHE and PYR observed away from the maize roots, with the highest dissipation rates recorded in rhizosphere zone in the central compartments of the rhizoboxes, followed by near rhizosphere zone and bulk soil zone in the outer compartments. However, G. mosseae only exerted minimal impacts on dissipation of PHE and PYR in the rhizosphere. The present study suggested that the hyphae and extraradical mycelium of AM fungi could play important roles in the uptake and translocation of PHE and PYR in plants. The present results indicated that there is a potential for the use of AM fungi and plant for remediating PAHs contaminated soils.
Journal of hazardous materials 01/2011; 187(1-3):341-7. · 4.14 Impact Factor
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ABSTRACT: Identifying prehistoric irrigated rice fields and characterizing the beginning of paddy soil development are important for a better understanding of human development and agricultural history. In 2003, paddy soils and irrigated rice fields buried at a depth of 100-130 cm were excavated at Chuo-dun-shan in the Yangtze River Delta, close to Suzhou, China. The fields of sizes between 1.4 and 16 m(2) were surrounded with ridges that were connected to ditches/ponds via outlets to control the water level within the fields. Many carbonized and partly carbonized rice grains with an age of 3,903 B.C. (measured (14)C age 5,129+/-45 a BP) were recovered. The surface layers of these buried paddy fields showed a high content of soil organic matter and a considerable high density of rice opals. The latter were identified to derive from Oryza spp. Solid-state (13)C nuclear magnetic resonance spectroscopy revealed aromatic carbon (C) as the predominant organic C form in the fossil surface layer. This is expected, if the major source represents burnt rice and straw. In summary, our data are in agreement with new evidences indicating that in China, paddy soils and irrigated rice cultivation were initiated and developed more than 6,000 years ago.
Naturwissenschaften 06/2006; 93(5):232-6. · 2.28 Impact Factor
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ABSTRACT: A survey was done recently in Jiaxing city of Zhejiang Province in the Yangtze River Delta to compare the differences of soil microbiological properties among paddy soils with different land use including continuous open-field vegetable cultivation (OFVC), plastic-greenhouse vegetable cultivation (PGVC) and traditional rice–wheat rotation (RWR). The soil types included are percolating, permeable and waterlogged paddy soils. The results indicate that the microbial flora was markedly changed as the land use changed for all the three soil types. In continuous vegetable cultivation soils, especially in PGVC soils, the bacteria amounts decreased dramatically, but the fungal and actinomyce amounts increased as compared with RWR soils. The dehydrogenase activities decreased significantly in vegetable soils, especially in PGVC soils as compared with RWR soils. The microbial biomass C and the total phospholipid contents (TPL) in vegetable cultivation soil greatly decreased as compared with RWR soils. Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in PGVC soils greatly decreased as compared with OFVC soils and RWR soils, revealing that microbial diversity had decreased since land use change. The activities of some soil enzymes including urease, invertase and phosphase were all lower in OFVC soils than those in RWR soils, and those in PGVC soils were the lowest. The degradation of microbiological activities in continuous vegetable cultivation soils, especially in PGVC soils, as compared with RWR soils might have been caused by soil acidification and accumulation of salts due to overuse of both organic and inorganic fertilizers in vegetable cultivation.
Environmental Geochemistry and Health 05/2004; 26(2):119-128. · 1.62 Impact Factor
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ABSTRACT: Field experiment was conducted to investigate the di-n-butyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) contamination in Capsicum annum fruit grown in DBP and DEHP contaminated soil, and to evaluate the effect of DBP and DEHP on the quality of capsicum fruit. The top layer soil (0-10 cm) of plots was treated with a mixture of DBP and DEHP (1:1 w/w) and capsicum seedlings were transplanted. After 90 days, capsicum fruit, shoot and root samples were collected. DBP and DEHP concentration in various parts of the samples were determined by gas chromatography. Vitamin C and capsaicin contents in fruit were determined using 2,4-dinitrophenylhydrazine colorimetric analysis and sodium nitrite-sodium molybdate colorimetric analysis, respectively. The results showed that DBP concentration in fruit, shoot and root increased with the increase of soil-applied DBP/DEHP concentration, but DEHP was not detected in all samples. When the soil-applied DBP/DEHP concentration was 5, 10, 20, 40, 80 and 160 mg kg(-1) soil, compared with control, vitamin C and capsaicin content in capsicum fruit decreased by 1.6%, 5.9%, 10.6%/o, 18.2%, 19.2%, 22.6% and 1.6%, 2.5%, 12.9%, 20.1%, 22.2%, respectively. Pearson correlation analysis demonstrated that the decrease of vitamin C and capsaicin content was negatively correlated to the increase of DBP concentration in capsicum fruit, which suggested that DBP uptake by the plant might be mainly responsible for quality degradation of capsicum fruit.
Chemosphere 03/2003; 50(6):801-5. · 3.21 Impact Factor
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ABSTRACT: A sand culture experiment was established to determine interactions between arbuscular mycorrhizae and heavy metals. Mycorrhizal infection rates, spore densities, maize root and shoot weights, and heavy metal contents in maize were as indexes of responses of arbuscular mycorrhizal fungi (Acaulospora laevis, Glomus caledonium and Glomus manihotis) to heavy metals (Cu and Cd). The mycorrhizal infection rates of G. caledonium were the highest among these three mycorrhizal fungi, but the sporulating ability of G. caledonium was the poorest in the heavy metal treatments. The shoot and root weights of non-mycorrhizal plants were usually greater than those of mycorrhizal plants when the Cu concentrations in solutions are less than 3 mg l(-1) or Cd concentrations less than 1 mg l(-1). When Cd concentrations were 0.5 and 1 mg(-1), the root and shoot weights of plants inoculated with A. laevis were significantly (p < 0.05) lower than those of other treatments. Copper concentrations in shoots of mycorrhizal plants were higher than those of non-mycorrhizal ones at all Cu concentrations in solution, especially at low Cu concentrations. As to A. laevis, Cu concentrations in roots and shoots of the host were higher than those of non-mycorrhizal plants in these treatments. Thus A. laevis was sensitive to Cu and Cd, especially Cd, and G. caledonium was more tolerant to these two heavy metals. It is suggested that G. caledonium might be a promising mycorrhizal fungus for bioremediation of heavy metal contaminated soil.
Chemosphere 03/2003; 50(6):847-53. · 3.21 Impact Factor
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ABSTRACT: Cowpea (Vigna sinensis L.) plants were inoculated with arbuscular mycorrhizal fungus (Acaulospora laevis) to investigate the effects of different concentrations of di-n-butyl phthalate (DBP; 0, 10, and 100 mg kg–1) added to soil on their growth. Mycorrhizal plants were less affected by high concentration of DBP (100 mg kg–1) than non-mycorrhizal ones. Also the uptake and transformation of DBP by mycorrhizal plants differed from that of non-mycorrhizal plants.
Biologia Plantarum 01/2003; 47(4):637-639. · 1.97 Impact Factor
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ABSTRACT: In the stereo matching process, a difficult task is to eliminate
the false match caused by the repetitive patterns and smooth patterns. A
new stereo matching technique that uses multiple image pairs in
orthogonal-directions has been proposed. First, it computes the sum of
squared-difference (SSD) values for each stereo pair in
orthogonal-directions. Then it simply adds individual SSD to produce the
sum of SSDs. The resulting function is called the OSSSD. We have proved
that the OSSSD function possesses a unique and clear minimum at the true
matching position, so it can easily remove the false match caused by
both repetitive and smooth patterns. A number of experiments with
synthetic and real image sequences are performed, and the results are
presented to demonstrate the effectiveness of the technique
Acoustics, Speech, and Signal Processing, 2000. ICASSP '00. Proceedings. 2000 IEEE International Conference on; 02/2000 · 4.63 Impact Factor
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ABSTRACT: In envelope-constrained filtering, the filter is optimized subject
to the constraint that the filter response to a given signal lies within
a specified envelope or mask. In a number of signal processing
applications, the envelope-constrained filtering problem is more
directly relevant than least squares approximation-based approaches. The
present authors develop an efficient method for solving an extended
version of the envelope-constrained filtering problem in which the input
pulse is not known exactly but is known to lie within a specified mask.
This envelope-constrained problem with uncertain input (ECUI) has been
examined elsewhere, but the algorithm proposed there for its solution
has, in general, inferior convergence characteristics
IEEE Transactions on Signal Processing 03/1994; · 2.63 Impact Factor
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ABSTRACT: The authors present a method for solving a class of optimization
problems with nonsmooth constraints. In particular, they apply the
method to the design of narrowband minimum-power antenna array
processors which are robust in the presence of errors such as array
element placement, look direction misalignment, and frequency offset.
They first show that the constrained minimum power problem has a unique
global minimum provided that the constraint set is nonempty. Then it is
shown how the design problem derived directly from considerations of the
sensitivity of the antenna array processor to errors can be transformed
into a quadratic programming problem with linear inequality constraints
which can be solved efficiently by the standard active set strategy.
They also present numerical results for two types of nonsmooth
constraints developed to provided robustness. These results confirm the
effectiveness of the method
IEEE Transactions on Antennas and Propagation 05/1993; · 2.15 Impact Factor
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ABSTRACT: Road tracking is a promising technique to increase the efficiency of road mapping. In this paper an improved road tracker, based on cooperation between angular texture signature and template matching, is presented. Our tracker uses parabola to model the road trajectory and to predict the position of next road centreline point. It employs angular texture signature to get the exact moving direction of current road centreline point, and moves forward one predefined step along the direction to reach a new position, and then uses curvature change to verify the new added road point whether right enough. We also build compactness of angular texture signature polygon to check whether the angular texture signature is suitable to be used to go on tracking. When angular texture signature fails, least squares template matching is then employed instead. Cooperation between angular texture signature and template matching can reliably extract continuous and homogenous ribbon roads on high resolution remotely sensed imagery.
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ABSTRACT: Metal(loid) accumulation and arbuscular mycorrhizal (AM) status of the dominant plant species, Cynodon dactylon, growing at four multi-metal(loid)s-contaminated sites and an uncontaminated site of China were investigated. Up to 94.7 As mg kg−1, 417 Pb mg kg−1, 498 Zn mg kg−1, 5.8 Cd mg kg−1 and 27.7 Cu mg kg−1 in shoots of C. dactylon were recorded. The plant was colonized consistently by AM fungi (33.0–65.5%) at both uncontaminated site and metal-contaminated sites. Based on morphological characteristics, fourteen species of AM fungi were identified in the rhizosphere of C. dactylon, with one belonging to the genus of Acaulospora and the other thirteen belonging to the genus of Glomus. Glomus etunicatum was the most common species associated with C. dactylon growing at metal-contaminated sites. Spore abundance in the rhizosphere of C. dactylon growing at the metal-contaminated soils (22–82 spores per 25 g soil) was significantly lower than that of the uncontaminated soils (371 spores per 25 g soil). However, AM fungal species diversity in the metal-contaminated soils was significantly higher than that in the uncontaminated soils. This is the first report of AM status in the rhizosphere of C. dactylon, the dominant plant survival in metal-contaminated soils. The investigation also suggests that phytorestoration of metal-contaminated sites might be facilitated using the appropriate plant with the aid of tolerant AM fungi.
Applied Soil Ecology 44(3):213-218. · 2.37 Impact Factor
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ABSTRACT: Recently, more and more high resolution remote sensing images appear, and they provide new data source for building extraction. Some building extraction methods are proposed to adapt to this trend. This paper addresses a semi-automatic method that combines segmentation and region selection. First, mean shift segmentation is applied to the image, and then the region extraction is implemented through the interactively selection of building parts. Edge detection is also involved to get the boundary of buildings. At last, the paper gives the contrast of the unsupervised classification ISODATA result and this extraction method.
Earth Observation and Remote Sensing Applications, 2008. EORSA 2008. International Workshop on;
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ABSTRACT: A survey was done recently in Jiaxing city of Zhejiang Province in the Yangtze River Delta to compare the differences of soil microbiological properties among paddy soils with different land use including continuous open-field vegetable cultivation (OFVC), plastic-greenhouse vegetable cultivation (PGVC) and traditional rice-wheat rotation (RWR). The soil types included are percolating, permeable and waterlogged paddy soils. The results indicate that the microbial flora was markedly changed as the land use changed for all the three soil types. In continuous vegetable cultivation soils, especially in PGVC soils, the bacteria amounts decreased dramatically, but the fungal and actinomyce amounts increased as compared with RWR soils. The dehydrogenase activities decreased significantly in vegetable soils, especially in PGVC soils as compared with RWR soils. The microbial biomass C and the total phospholipid contents (TPL) in vegetable cultivation soil greatly decreased as compared with RWR soils. Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in PGVC soils greatly decreased as compared with OFVC soils and RWR soils, revealing that microbial diversity had decreased since land use change. The activities of some soil enzymes including urease, invertase and phosphase were all lower in OFVC soils than those in RWR soils, and those in PGVC soils were the lowest. The degradation of microbiological activities in continuous vegetable cultivation soils, especially in PGVC soils, as compared with RWR soils might have been caused by soil acidification and accumulation of salts due to overuse of both organic and inorganic fertilizers in vegetable cultivation.
Environmental Geochemistry and Health 26(2-3):119-28. · 1.62 Impact Factor
