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231.
Nitrogen Removal by Riparian Buffers along a European Climatic Gradient: Patterns and Factors of Variation 总被引:9,自引:1,他引:8
Sergi Sabater Andrea Butturini Jean-Christophe Clement Tim Burt David Dowrick Mariet Hefting Véronique Matre Gilles Pinay Carmen Postolache Marek Rzepecki Francesc Sabater 《Ecosystems》2003,6(1):0020-0030
We evaluated nitrogen (N) removal efficiency by riparian buffers at 14 sites scattered throughout seven European countries
subject to a wide range of climatic conditions. The sites also had a wide range of nitrate inputs, soil characteristics, and
vegetation types. Dissolved forms of N in groundwater and associated hydrological parameters were measured at all sites; these
data were used to calculate nitrate removal by the riparian buffers. Nitrate removal rates (expressed as the difference between
the input and output nitrate concentration in relation to the width of the riparian zone) were mainly positive, ranging from
5% m−1 to 30% m−1, except for a few sites where the values were close to zero. Average N removal rates were similar for herbaceous (4.43% m−1) and forested (4.21% m−1) sites. Nitrogen removal efficiency was not affected by climatic variation between sites, and no significant seasonal pattern
was detected. When nitrate inputs were low, a very large range of nitrate removal efficiencies was found both in the forested
and in the nonforested sites. However, sites receiving nitrate inputs above 5 mg N L−1 showed an exponential negative decay of nitrate removal efficiency (nitrate removal efficiency = 33.6 e−0.11 NO3input, r
2
= 0.33, P < 0.001). Hydraulic gradient was also negatively related to nitrate removal (r = −0.27, P < 0.05) at these sites. On the basis of this intersite comparison, we conclude that the removal of nitrate by biological mechanisms
(for example, denitrification, plant uptake) in the riparian areas is related more closely to nitrate load and hydraulic gradient
than to climatic parameters.
Received 15 August 2001; accepted 2 May 2002. 相似文献
232.
Tetsuya Nojima Annika Rings Aaron M. Allen Nils Otto Thomas A. Verschut Jean-Christophe Billeter Megan C. Neville Stephen F. Goodwin 《Current biology : CB》2021,31(6):1175-1191.e6
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233.
Amplified fragment length polymorphism (AFLP) was used to obtain information on the within-species genetic variability of the tobacco cyst-nematode (TCN) complex. AFLP was found to be well suited to this type of study. The current classification of TCN was confirmed. Results indicate that the Globodera tabacum solanacearum group, believed to be restricted to the U.S.A., also occurs in Mexico. The within-species variability of TCN is considerable. Populations from Mexico may form a new subgroup. AFLP group-specific markers were identified for two of the TCN subgroups: Globodera tabacum tabacum and Globodera tabacum solanacearum. 相似文献
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235.
Elodie Jagu Sébastien Pomel Stéphanie Pethe Jean-Christophe Cintrat Philippe M. Loiseau Raphaël Labruère 《Bioorganic & medicinal chemistry letters》2019,29(14):1710-1713
This study describes the synthesis of fluorescent probes as potential substrates for the polyamine transport system (PTS) of Leishmania donovani. A competitive radioassay was used to determine the most efficient probe. We observed that the conjugate spermine-nitrobenzofurazan (Spm-NBD) was able to compete with [3H]-spermidine in L. donovani at a potent IC50 of 60 µM. 相似文献
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237.
David Roux Alexandre Catrain Sébastien Lallechere Jean-Christophe Joly 《Plant signaling & behavior》2015,10(1)
We have monitored the electrical potential variations (EPV) of sunflower plants illuminated by a high-intensity microwave-frequency (2.5 GHz, 1.5 kV/m) electromagnetic field (EMF). We have designed an appropriate set-up that allows parallel temperature and EPV measurements while part of the plant is being exposed to the field. The results show that the considered EMF does not induce plant EPV directly. This electrophysiological response appears only when the EMF leads to a mechanical injury of the tissues via a thermal effect (dielectric heating). Once the plant inner temperature reached a threshold, we systematically observed burn-like lesions associated with the bending of the stem or leaf-stalks. Theses mechanical constraints were rapidly followed by EPVs, moving through the stem. 相似文献
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