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41.
Oleg Daugovish Ben Faber Michael Cahn Surendra Dara 《International Journal of Fruit Science》2016,16(4):108-117
ABSTRACTStrawberry transplants in California are planted through narrow holes in raised beds covered with polyethylene mulch. They are irrigated with overhead sprinklers for the first five weeks to leach salts and maintain plant turgidity; most of this sprinkler-applied water runs off the plastic without reaching the plants. At three coastal locations, we compared grower controlled drip irrigation with doubled number of tapes to sprinkler irrigation immediately after planting. Root zone EC and moisture levels were similar in both irrigation systems. Depending on the location, water use was reduced 24 to 78% in drip-only plots compared to sprinkler and runoff was nearly eliminated. Plants in drip-only plots were similar in size and root biomass to those established with sprinkler irrigation. Early yields were similar in the two irrigation systems. Thus, use of the increased number of drip tapes conserves water during strawberry establishment without negative effects on plant performance. 相似文献
42.
Maxim S. Kokoulin Lyudmila A. Romanenko Aleksandra S. Kuzmich Oleg Chernikov 《Marine drugs》2021,19(12)
Two cell-wall-associated polysaccharides were isolated and purified from the deep-sea marine bacterium Devosia submarina KMM 9415T, purified by ultracentrifugation and enzymatic treatment, separated by chromatographic techniques, and studied by sugar analyses and NMR spectroscopy. The first polysaccharide with a molecular weight of about 20.7 kDa was found to contain d-arabinose, and the following structure of its disaccharide repeating unit was established: →2)-α-d-Araf-(1→5)-α-d-Araf-(1→. The second polysaccharide was shown to consist of d-galactose and a rare component of bacterial glycans-d-xylulose: →3)-α-d-Galp-(1→3)-β-d-Xluf-(1→. 相似文献
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44.
Yuzikhin O Mitina G Berestetskiy A 《Journal of agricultural and food chemistry》2007,55(19):7707-7711
Stagonospora cirsii is a pathogen of Cirsium arvense, causing necrotic lesions on leaves of this noxious weed. The fungus produced toxic metabolites when grown in liquid culture. A new phytotoxin, named stagonolide, was isolated and characterized as (8R,9R)-8-hydroxy-7-oxo-9-propyl-5-nonen-9-olide by spectroscopic methods. Stagonolide was shown to be a nonhost-specific but selective phytotoxin. Leaves of C. arvense were most sensitive and leaves of tomato and pepper (both Solanaceae) were less sensitive to stagonolide, which was assayed at 5 x 10(-3) M, than other plants. Stagonolide assayed at 5 x 10(-6) M was demonstrated to be a strong inhibitor of root growth in seedlings of C. arvense and some other Asteraceae species. Seedlings growth in wheat and radish was much less affected by the toxin, and seedlings of cucumber were insensitive to it. 相似文献
45.
Marié JL Davoust B Socolovschi C Mediannikov O Roqueplo C Beaucournu JC Raoult D Parola P 《Comparative immunology, microbiology and infectious diseases》2012,35(1):59-62
The aim of our study was to detect the presence of Rickettsia spp. and Bartonella spp. in ticks and fleas collected from red foxes (Vulpes vulpes) in southeastern France during 2008. Using a genus-specific quantitative PCR (qPCR) assay, which was followed by a species-specific qPCR assay for the positive samples, 45.2% (33/73) of ticks (Rhipicephalus turanicus) were found to be infected with Rickettsia massiliae. 10.5% (2/19) of the fleas (Archaeopsylla erinacei) collected in the study tested positive for Rickettsia felis. A genus-specific qPCR assay did not reveal any Bartonella species in any of the ticks or fleas collected. The role of red foxes in the epidemiology of spotted fever caused by Rickettsiae species requires further investigation. 相似文献
46.
Purpose
The fractionation of soil humic acids (HAs) according to their hydrophobicity is a common procedure in the study of this polydispersed complex natural mixture, so that reversed-phase high-performance liquid chromatography (RP-HPLC) is used resulting in humic components of differing hydrophobic/hydrophilic properties. However, a comparative study of the hydrophobicity of fractions isolated from different soil HAs have not been addressed so far.Materials and methods
The RP-HPLC with online absorbance detection was used for analysis of International Humic Substances Society soil standard HAs, chernozem soil HAs, and their electrophoretic fractions A, B, and C?+?D, obtained by tandem size exclusion chromatography–polyacrylamide gel electrophoresis. The strong relationship between hydrophobicity, electrophoretic mobility (EM), molecular size (MS), specific absorbance at 280 nm and aromaticity of HAs fractions was found.Results and discussion
Independently of soil HAs genesis fraction A with lowest EM and highest MS is essentially more hydrophobic (60–73 % of the fraction amount remained adsorbed on the RP column) than medium EM and MS fraction B (33–47 % of the fraction amount remained adsorbed on the RP column). The lowest hydrophobicity belongs to fraction C?+?D with highest EM and lowest MS.Conclusions
The most hydrophilic aromatic fraction C?+?D seems to have been bound with other mostly aliphatic hydrophobic fractions A and B through non covalent (possibly hydrogen) bonds. These data could be relevant to better understanding the overall makeup of soil HAs and their structural organization. 相似文献47.
Carbon-fluorine bonds are among the most unreactive functionalities in chemistry. Interest in their activation arises in part from the high global warming potentials of anthropogenic polyfluoroorganic compounds. Conversion to carbon-hydrogen bonds (hydrodefluorination) is the simplest modification of carbon-fluorine bonds, but efficient catalytic hydrodefluorination of perfluoroalkyl groups has been an unmet challenge. We report a class of carborane-supported, highly electrophilic silylium compounds that act as long-lived catalysts for hydrodefluorination of trifluoromethyl and nonafluorobutyl groups by widely accessible silanes under mild conditions. The reactions are completely selective for aliphatic carbon-fluorine bonds in preference to aromatic carbon-fluorine bonds. 相似文献
48.
Amblyomma parvum is a widespread Neotropical tick found on several domestic animals and is known to harbor a Rickettsia species of yet unknown pathogenicity. However its life cycle on, and suitability of, several of these hosts has not been described. In this work the biology of A. parvum is presented when fed on seven domestic hosts (chicken, dog, rabbit, horse, guinea pig, cattle and goat). The complete life cycle of the tick varied from 96.8 to 102 days. Highest engorgement weight of larvae was from ticks fed on horses and that of nymphs from guinea pigs. Highest larval yield was from guinea pigs and that of nymphs from horses. Engorged female and egg mass weights, yield and conversion of female weight to eggs rates were the highest in dog ticks and the lowest in goat ticks. The highest egg hatching rate was seen in ticks from dogs and the lowest in ticks from cattle. Overall it was seen that dogs were the best host for adult A. parvum ticks, and guinea pigs for immatures. Horses were also shown to be a good host for all tick stages. It can thus be affirmed that A. parvum is a host generalist tick, and its distribution is probably determined by environmental requirements rather than by hosts. 相似文献
49.
ABSTRACTField experiments were conducted in 2013 and 2014 to evaluate the predation efficacy of four commercially available predatory mites (Phytoseiidae): Phytoseiulus persimilis, Neoseiulus californicus, N. fallacis, and Amblyseius andersoni, for control of twospotted spider mite (Tetranychus urticae Koch) and Lewis spider mite (Eotetranychus lewisi) in strawberries. In the 2013 experiment, a grower standard treatment (P. persimilis and N. californicus) was compared to single treatments of each phytoseiid species. The 2014 experiment excluded N. fallacis as a treatment, but all other treatments are the same as in 2013. For both seasons, all treatments decreased both two-spotted and Lewis spider mite populations immediately after releases equivalently. However, none of the treatments tested were able to keep twospotted and Lewis spider mite populations below the economic threshold level. These findings indicate that several releases will be needed throughout the growing season in order to maintain spider mite levels below the economic thresholds. 相似文献
50.
Ludmila Limantseva Nina Mironenko Oleg Shuvalov Olga Antonova Alexandr Khiutti Lubov Novikova Olga Afanasenko David Spooner Tatjana Gavrilenko 《Plant Breeding》2014,133(5):660-665
Potato cyst nematodes (PCN) collected in six localities in the Leningrad region of North West Russia were identified as Globodera rostochiensis pathotype Ro1 and were used for subsequent resistance tests. Seventy‐nine accessions of cultivated and closely related wild potato species from the VIR collection in Russia were screened on resistance to G. rostochiensis pathotype Ro1 and on the presence of molecular markers for H1 and Gro1‐4 resistance genes. No associations were detected between the resistance level of diploid and tetraploid Andean and tetraploid Chilean potato landraces (indigenous cultivars) and their related wild species and their geographical distribution or presence of PCR‐based markers that are associated with the H1 and Gro1‐4 genes. At the same time, all susceptible genotypes lacked such markers. New sources of resistance were found and could be used in breeding. 相似文献