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101.
Comesaña Losada M Leão JM Gago-Martínez A Rodríguez Vázquez JA Quilliam MA 《Journal of agricultural and food chemistry》1999,47(2):618-621
Further studies on mussel samples from Galicia, Spain, have revealed the presence of okadaic acid (OA), dinophysistoxin 2 (DTX2), and the fatty acid acyl esters of both of these toxins as the "DTX3" complex. Measurements were performed with an improved in situ method for the formation of 9-anthryldiazomethane (ADAM) derivatives followed by liquid chromatography with fluorescence detection. Base hydrolysis of DTX3 toxins gave free OA and DTX2, which were determined following ADAM derivatization. Results were confirmed by liquid chromatography/mass spectrometry analyses, and in most of the samples, free DTX2 was the most abundant toxin. However, the OA/DTX2 ratio in the DTX3 conjugated form was different, with OA being the most abundant in all cases. This difference could be due to different rates of metabolism of OA and DTX2 to the acyl esters or due to contamination of the shellfish by the two toxins at different points in time, resulting in less acyl ester formation for one toxin versus the other. The second possibility would be reasonable if two different source organisms were producing the toxins. 相似文献
102.
Silvana Creste Augusto Tulmann Neto Roland Vencovsky Sebastião de Oliveira Silva Antonio Figueira 《Genetic Resources and Crop Evolution》2004,51(7):723-733
Banana (Musa spp.) is one of the most consumed fruits worldwide. Production is based mainly on triploid cultivars, and most genetic improvement programs aim to generate tetraploid hybrids obtained from the crossing of established triploid cultivars with a diploid parent genotype, improved or wild, exhibiting the trait of interest, normally resistance to biotic factors. Microsatellites were used to investigate the genetic variability and relationships between 58 Musa genotypes, including 49 diploids and nine triploid cultivars maintained at the Musa germplasm collection of the Brazilian dessert banana breeding program. Thirty-three primer pairs developed for banana were tested, and nine amplified reproducible and discrete fragments, producing a total of 115 alleles. The average number of alleles amplified per primer was 12.8, ranging from 10 to 15. The diploid genotypes presented the largest genetic variability, demonstrated by the large number of alleles detected, and the low similarity between the clones. The phenetic analysis clustered the triploid cultivars in a separated group, with the exception of the Nanica and Gros Michel cultivars, which showed high similarity with the diploid cultivar Mambee Thu. It was not possible to separate the wild diploid genotypes from the cultivated ones, indicating a common origin of these genotypes. A high proportion of duplicated alleles and/or loci was observed for diploid and triploid genotypes. The information gathered about the similarity between diploid and triploid accessions will help to define potential crosses to maximize the recovery of the typical fruit qualities required in Brazil (AAB, Pome and Silk dessert banana). 相似文献
103.
Water and nutrients were supplied to anEucalyptus globulus plantation in a controlled experiment in west central Portugal. The trees were planted in a sandy soil at a spacing of 3 × 3 m. The experiment consisted of four treatments: irrigation, irrigation plus fertilization, fertilization without irrigation, and a rain fed and unfertilized control. The quantification of root biomass was carried out 13 mo after planting. When the plantation was 31 mo old, a trench was dug in the soil to uncover the distribution of the roots of individual trees. In the irrigated treatments root biomass was higher than in the control and in the fertilized plots. Differences in fine and coarse root distribution along the soil profile were also observed. In both irrigated treatments roots were concentrated along tree rows, where the irrigation tubes were dripping water or water plus nutrients. 相似文献
104.
D.?RubialesEmail author M.?T.?Moreno J.?C.?Sillero 《Genetic Resources and Crop Evolution》2005,52(7):853-861
Orobanche crenata Forsk. is a major constraint for pea production in Mediterranean and East Asian countries. To solve the problem of the lack of
resistance in pea cultivars, a screening for resistance was performed under field conditions in a germplasm collection of
575 accessions of Pisum sativum L. No complete resistance was found but varying levels of resistance were identified and confirmed in further field seasons
and in pots experiments in the greenhouse. Resistance was quantitative resulting in a reduction in the number of emerged broomrapes
per pea plant. Broomrape infection and expression of resistance proved to be highly influenced by environmental conditions.
Resistance is the consequence of the combination of several resistance mechanisms preventing or hampering establishment of
broomrape and/or development of established tubercles. Resistance identified could suffice to prevent broomrape damage in
normal years, but might need to be implemented with other control measures in very conducive years. Resistant accessions have
been crossed with pea cultivars and submitted to a breeding programme in which accumulation of levels of resistance to broomrape
is a priority. 相似文献
105.
Magalhães V. F. Carvalho C. E. V. Pfeiffer W. C. 《Water, air, and soil pollution》2001,129(1-4):83-90
Arsenic distribution and dispersion in sediments of the EngenhoInlet and the Sepetiba Bay were investigated in order to evaluate the extent of the contamination caused by a metallurgical plant installed in the Sepetiba Bay watershed. The ore used in the smelting process, the soil around the plant, and ore waste collected inside the plant were also analyzed for As. Very high As concentrations in the stronglyand weakly bound fractions (up to 63 000 and 52 700 μgg-1, respectively) were found in the ore waste. The soilsalso contained high concentrations of both the strongly andweakly bound fractions (748 and 636 μg g-1, repectively), although the ore itself contained lower levelsof the two fractions (63 and 13 μg g-1, respectively).The sediments of the Engenho Inlet had a high degree of contamination (up to 347 μg g-1) decreasing toward Sepetiba Bay where the lowest concentrations were found (up to 50 μg g-1). Altough lower concentrations were found in the Sepetiba Bay sediments, they are 5 times higher than the world average. The results showed that there is an As transport from the Engenho Inlet to the Sepetiba Bay. These results suggests that the bay's fish and mollusk stock my be contaminated. This contamination may adversely affect the health of the local population, whose main protein supply is seafood. 相似文献
106.
Luis Miguel Brito Áurea Sampaio Rui Pinto Isabel Mourão João Coutinho 《Journal of plant nutrition》2016,39(6):842-849
The response of lettuce to production system, organic and phosphate fertilizers and root mycorrhization, was evaluated in two pot trials with factorial treatment combination of: (i) soil type (from organic and from conventional production systems) and organic fertilizer (0, 2 and 4 t ha?1) in the first trial; and (ii) mycorrhizal inoculation (mycorrhized and non-mycorrhized plants) and Gafsa phosphate (0, 100 and 200 kg P2O5 ha?1) in the second. Lettuce growth decreased with increasing rates of the organic fertilizer because of its very high electrical conductivity (50.1 dS m?1) and lack of maturation. However, the fertilizer harmful effects were minimized in the soil from organic production. The application of Gafsa phosphate significantly increased lettuce yield and nutrient uptake. However, for the highest rate of phosphate, mycorrhized lettuce yield decreased compared to non-mycorrhized lettuce, suggesting that high soil available P may have harmful effects on the activity of mycorrhizal fungi. 相似文献
107.
108.
João S. Dias 《Genetic Resources and Crop Evolution》1995,42(4):363-369
Nuclear RFLPs were used to study the genetic relationships of 2 Portuguese coles, tronchuda cabbage and Galega kale, and 13
otherBrassica oleracea cultivars and 4 nine-chromosome wild brassicas. Cluster and principal coordinates analysis were conducted using RFLP data
from 60 probe-enzyme combinations, detecting 277 polymorphic restriction fragments. The results showed that the accessions
clustered in five groups: one with all theB. oleracea cultivars except kailan, and the four others isolated with kailan, wildB. oleracea, B. insularis andB. cretica, andB. montana, respectively. Kailan was separated from the other accessions ofB. oleracea cultivars and genetically close to the wildB. oleracea, that was clearly separated from the other nine-chromosome wild brassicas. In theB. oleracea cultivars 3 groupings were clearly individualized: i) including broccolis and cauliflower; ii) with a misture of kales and
cabbages originally from Central-North Europe; iii) formed by Portuguese coles. These preliminary results suggest the existence
of three major regions of domestication of B. oleracea in Europe: Italy, Central-North Europe and Portugal. Kailan or chinese
kale seems to have evolved separately from the otherB. oleracea cultivars in Eastern Asia. 相似文献
109.
Antioxidant properties of trans-epsilon-viniferin as compared to stilbene derivatives in aqueous and nonaqueous media 总被引:3,自引:0,他引:3
Privat C Telo JP Bernardes-Genisson V Vieira A Souchard JP Nepveu F 《Journal of agricultural and food chemistry》2002,50(5):1213-1217
trans-Epsilon-viniferin, the dimer of resveratrol, extracted from Vitis vinifera, has been evaluated for its antioxidant capacity. Its properties have been compared to those of resveratrol and synthetic stilbenic derivatives (4-hydroxystilbene, 4,4'-dihydroxystilbene, 3,5-dihydroxystilbene, and trimethylresveratrol), in regard to their liposolubility using two media with different polarity. The bleaching of beta-carotene by lipoperoxyl (LOO.) radicals in an oil/water (O/W) emulsion and the scavenging of superoxide anions (O(-)(2) in dimethyl sulfoxide (DMSO) using 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap were followed using UV-visible and electron paramagnetic resonance, respectively. Epsilon-viniferin exhibits the best antioxidant capacity in the DMSO/O(-)(2) polar system (IC(50) = 0.14 mM) while 4,4'-dihydroxystilbene presents the highest antioxidant capacity in the O/W/LOO. system (inhibition of beta-carotene bleaching, 82%). Partition coefficients and kinetics of partition between 1-octanol and water were measured to discuss the antioxidant efficiency of the compounds in relation with their chemical structure. 相似文献
110.
Celia Dias-Ferreira Rosinda L. Pato Jorge B. Varejão Alexandre O. Tavares Antonio J. D. Ferreira 《Journal of Soils and Sediments》2016,16(11):2594-2605