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1.
Cornus stolonifera, Salix petiolaris, and Spiraea alba
clones already located within the corridor of an electrical power line. To
establish the efficiency of treatments, we examined the statistical
differences of growth traits between species and treatments.
An analysis of the effects of layering shows, after the first growth season,
differences for all growth traits in only one species, Spiraea alba.
After the second growth season, we observed the development of new aerial
stems. Layering favors horizontal expansion of shrubs over height
development. The third year after treatment, the effect of layering is
reduced except for Cornus stolonifera, which continuously increases,
as shown by the significant progression of the clone issued from the layer
even five years after treatments. With the cutting back technique, we
expected a distinct vertical growth of the shrubs at the expense of
increasing the crown diameter. This technique would be best associated with
the rejuvenation of clones, followed by a layering of new shoots to allow a
horizontal expansion of the shrubs. Therefore, the formation of a dense shrub
community by layering should be considered a valuable approach for the
biological control of undesirable trees in powerline rights-of-way. 相似文献
2.
Dominique Calmet 《Chemistry and Ecology》1992,6(1):41-49
For hundreds of years, the seas have been used as a place to dispose of wastes from human activities. Although no high level radioactive waste has been disposed of into the sea, variable amounts of packaged low level radioactive wastes have been dumped at 47 sites in the northern part of the Atlantic and Pacific Oceans. in 1946 the first sea dumping operation took place at a site in the North-East Pacific Ocean. the last dumping operation was in 1982, at a site off the European continental shelf in the Atlantic Ocean. Between these two dates, an estimated 46 PBq (1.24 MCi) of radioactive waste coming from research, medical, military and industrial activities have been disposed of at sea. the present trend, through the Convention for the Prevention of Marine Pollution by Dumping of Wastes and other Matter and other Regional Conventions, points towards the prohibition of the dumping of any radioactive waste into the marine environment. 相似文献
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We report relatively high citrulline concentration in amniotic fluid of a citrullinemic fetus suggesting that prenatal detection of this condition could be done on this basis in conjunction with a direct or an indirect determination of argininosuccinate synthetase activity in amniotic fluid cells. 相似文献
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Marhuenda-Egea FC Martínez-Sabater E Jordá J Moral R Bustamante MA Paredes C Pérez-Murcia MD 《Chemosphere》2007,68(2):301-309
The aim of the present paper is to assess the maturity degree reached by different samples of several mixtures from winery and distillery residues composted using the Rutgers composting system, by means of excitation-emission matrix (EEM) fluorescence spectroscopy. The composts were sampled once a week for about 200d. EEM spectra indicate the presence of different fluorophores. The fluorescence intensities of these peaks show trends related to the maturity of the composting samples selected. The "contour density" of EEM maps is strongly modified through time. We have used the quantitative method of fluorescence regional integration (FRI). The EEMs were delineated into five excitation-emission regions. The degree of compost maturity could be correlated with the percentage of the volumetric integration under the EEM within each region. Further refinement of these techniques should provide a relatively rapid method for assessing the suitability of the compost to soil application. 相似文献
9.
Characterization of food waste and bulking agents for composting 总被引:1,自引:0,他引:1
The characterization of food waste (FW) and locally available bulking agents (BA) are a prerequisite to optimizing compost recipes. This study measured the variation in FW characteristics (pH, dry matter (DM), carbon (C), wet bulk density and Total Kjeldahl Nitrogen (TKN)) produced by a restaurant and a community kitchen in downtown Montreal, Canada from May to August 2004. The project also measured the mass of FW produced by another restaurant and a group of 20-48 households, from June to August 2004. Locally available BA (hay, straw, pine wood shavings, cardboard, left over cattle feed and wheat residue pellets) were also characterized to formulate composting recipes based on the FW characteristics observed during a period representative of winter and summer conditions. Residential and restaurant FW characteristics varied significantly over the summer months, although the mass produced remained constant at 0.61 and 0.56 kg capita(-1)day(-1), respectively. In addition, the number of customers served by the restaurant increased by nearly 50% from June to August. The BA with the highest moisture adsorption capacity was found to be the wheat residue pellets, followed by chopped straw. Wheat residue pellets, chopped hay and left over cattle feed all presented a balanced C/N ratio. Wheat residue pellets and wheat straw, chopped hay and cardboard demonstrated neutral pH values. Based on the variable FW characteristics and monthly production rates, the formulation of recipes indicates that compost facilities must be flexible enough to handle seasonal variations of as much as 50% by volume. 相似文献
10.
Comparison of arsenic resistance in Mediterranean woody shrubs used in restoration activities 总被引:1,自引:0,他引:1
Myrtus communis, Arbutus unedo and Retama sphaerocarpa are Mediterranean shrubs widely used in revegetation of semiarid degraded soils. The aim of this work is to study the resistance of these plants to arsenic under controlled conditions, in order to evaluate their potential use in revegetation and/or phytoremediation of As-polluted soils. R. sphaerocarpa showed higher resistance to As than M. communis or A. unedo according to its higher EC50, P status and P/As molar ratio in both, roots and shoots, and the lower increases in lipid peroxidation and decrease of chlorophyll levels in response to arsenic, while the highest arsenate sensitivity was obtained for A. unedo. Arsenic was mainly retained in roots, and, although M. communis accumulated higher arsenic amounts than the other two species, R. sphaerocarpa showed the highest root to shoot transfer. Most of the studied parameters (chlorophylls, MDA and total thiols) showed significant correlation with arsenic concentration in roots and leaves of plants, so they can be useful indexes in the diagnosis of arsenic toxicity in these species. According to our results, both M. communis and R. sphaerocarpa could be used in the revegetation of moderately arsenic contaminated sites. 相似文献