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41.
Thomas C. Hutchinson Leah Bozic Guadalupe Munoz-Vegas 《Water, air, and soil pollution》1986,31(1-2):283-294
Seedlings of red, white and black spruce, and white and jack pine were tested for their response to a range of Al concentrations, when grown for 12 to 14 weeks in sand culture in the greenhouse. Nutrients were supplied in solution of pH 3.8 to which Al was supplied at 0, 5, 10, 20, 40, 80 and 160 mg/L. Red and white spruce were inhibited in growth from 5 mg/L upwards, while black spruce was equally inhibited only at concentrations > 20 mg/L. In contrast, white pine was stimulated by 5 to 20 mg Al/L and was always more tolerant than the other 4 species at every Al level used. Jack pine was intermediate in its response. There was a positive linear relationship between P and Al accumulation in the shoots of red spruce. This was in contrast to the other 4 species in which P concentrations in the shoot decreased with an increase in Al concentrations. In localization studies on jack pine using a modified hematoxylin stain, Al was shown to accumulate in the root cap of root tips, and in the epidermal and outer cortical walls of older roots. EDAX-SEM analysis confirmed the tissue distribution of Al and revealed its coincidental distribution with. P in roots. 相似文献
42.
Aparicio-Fernandez X Yousef GG Loarca-Pina G de Mejia E Lila MA 《Journal of agricultural and food chemistry》2005,53(11):4615-4622
The common bean contains phytochemicals, including phenolic compounds, which can provide health benefits to the consumer. Our objective was to characterize the polyphenolic compounds present in the seed coat of Black Jamapa bean and to test fractionation methods that permit the recovery of polyphenolics in their naturally occurring forms. A 100% methanol extract from seed coats was subjected to different chromatographic fractionation methods. Analysis by HPLC-MS revealed that a better separation of phytochemicals was achieved using direct silica gel fractionation, which allowed more accurate identification of compounds, especially of the flavonols. Anthocyanins, flavanol monomers, and heterogeneous flavanol oligomers up to hexamers were detected. To our knowledge, this is the first time that myricetin glycoside and proanthocyanidin oligomers containing (epi)-gallocatechin have been reported in the black bean. The fractionation methods used in this study produced large quantities of natural mixtures of flavonoids suitable for testing bioactivity and phytochemical interactions. 相似文献
43.
Luis?J.?álvarezEmail author Adrián?A.?Fernández-Bremauntz Eliane?R.?Rodrigues Guadalupe?Tzintzun 《Journal of Agricultural, Biological & Environmental Statistics》2005,10(3):276-290
Exposure to high levels of pollution is a persistent problem in large cities throughout the world. The ability to predict
the occurrence of a high level of a pollutant allows environmental authorities to take preventive measures, such as controlling
the emission of pollution. Communities and officials can also take actions to reduce the exposure of susceptible groups in
the population. Therefore, being able to estimate the behavior of a given pollutant is of great importance. In this article
we use a Markov chain model to study this behavior. In order to do so, we consider the sequence of the daily maximum measurements
of a pollutant and let successive intervals containing them follow a Markov chain of order K>-0. The novelty here is that we allow K to be a random variable and estimate it and the corresponding transition probabilities using a maximum a posteriori method. The results are used to perform estimations about the behavior of ozone levels in Mexico City. 相似文献
44.
Bustos G Moldes AB Cruz JM Domínguez JM 《Journal of agricultural and food chemistry》2004,52(4):801-808
Lees coming from different steps in white wine and red wine vinification were characterized under physicochemical analyses to determine the content in carbon, nitrogen, ashes, solids in suspension, organic compounds, and minerals. Due to the hydrolytic activity of Lactobacillus strains, lees without autolysis treatments were used directly as the unique nutrient or in combination with corn steep liquor to carry out the glucose to lactic acid fermentation with Lactobacillus rhamnosus CECT-288. Time courses of glucose and lactic acid were modeled according to reported models. Using 20 g/L of lees coming from the white wine technology and re-collected after the second decanting step before distillation, as the only nutrient, the values achieved (P = 105.5 g/L, Q(P) = 2.470 g/L.h) were even higher than those obtained with the costly MRS broth (P = 104.3 g/L, Q(P) = 2.251 g/L.h). 相似文献
45.
Rosalía Núñez-Pastrana Guadalupe Fabiola Arcos-Ortega Ramón Armando Souza-Perera Carlos Alberto Sánchez-Borges Yumi Elena Nakazawa-Ueji Francisco Javier García-Villalobos Adolfo Alberto Guzmán-Antonio José Juan Zúñiga-Aguilar 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(4):669-683
46.
Guadalupe Williams-Linera Claudia Alvarez-Aquino Estela Hernández-Ascención María Toledo 《New Forests》2011,42(2):131-148
Secondary successional vegetation represents one-third of the 7% of the original area covered with tropical dry forest that
remains in central Veracruz, Mexico. In this region, fallow periods are short, in general, no longer than 7–10 years, and
old secondary successional sites are not available. Therefore we evaluated the potential of very early successional stages
of tropical dry forest with different land use histories for recovering the structure and composition of regional forest.
We compared five early successional sites (7–72 months) with five nearby forest remnants. Successional sites had reached 38
and 30%, respectively, of the average basal area and density recorded for the forest understories, but only 5 and 10%, respectively,
of the basal area and density of forest overstories. A total of 132 tree species were recorded, 45 at successional and 107
at forest sites. Individuals of tree species with animal-dispersed seeds (57%) were significantly better represented than
wind-dispersed (22%) and self-dispersing (21%) species in both successional and forest sites. Successional sites had already
recruited 10% of the intermediate and shade-tolerant species that grow in forest remnants. However, only 20 species occurred
in both early successional and forest sites, several showing resprouting ability. We conclude that the entry of forest species
to the successional process at very early stages and the recruitment of individuals from resprouting may facilitate the recovery
of the dry forest in Veracruz. 相似文献
47.
Antioxidant activity in common beans (Phaseolus vulgaris L.) 总被引:4,自引:0,他引:4
Cardador-Martínez A Loarca-Piña G Oomah BD 《Journal of agricultural and food chemistry》2002,50(24):6975-6980
Beans were pearled to evaluate the feasibility of increasing antioxidant activity and phenolic antioxidants. Phenolics were concentrated mostly in the hull fraction at about 56 mg of catechin equivalents per gram of sample. The methanolic extracts of the pearled bean samples were screened for antioxidant potential using the beta-carotene-linoleate and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) in vitro model systems. The pearled material, also referred to as milled samples, exhibited antioxidant activity that correlated with phenolic content and inhibited DPPH significantly in a dose-dependent manner. Phenolics and antioxidant activities were also examined in chromatographic fractions of methanolic extracts of manually obtained hulls that represented a model used previously to ascertain antimutagenic activity. Fractions extracted with ethyl acetate/acetone and acetone displayed antioxidant activity, which implies potent free radical scavenging activity with antimutagenic activity. 相似文献
48.
González-Larena M García-Llatas G Vidal MC Sánchez-Siles LM Barberá R Lagarda MJ 《Journal of agricultural and food chemistry》2011,59(8):3624-3631
The content of plant sterol (PS) and their oxidation products (POPs) in eight ingredients used to enrich functional foods was studied. A gas chromatographic (GC) technique with mass-spectrometric detection was used for identification, while GC with a flame ionization detector (GC-FID) was used for quantification. β-Sitosterol was the most abundant phytosterol, and the main POPs found were derived from this compound (7α/β-hydroxysitosterol, 7-ketositosterol, and sitostanetriol). The total amount of POPs found in the ingredients ranged from 29.03 to 110.02 μg/100 g PS. The β-sitosterol oxidation rates ranged from 10 to 50 μg β-sitosterol oxides/100 g of β-sitosterol. In view of this low rate of oxidation in the ingredients tested, it can be concluded that the PS remain stable in these ingredients. Significant correlations (p < 0.01) were found between total oxysitosterols versus β-sitosterol contents (R(2) = 86.5%) and between total POPs and total PS (R(2) = 81.6%). 相似文献
49.
de la Peña-Baca Daniel Alejandro Romo-Chacón Alejandro Rios-Velasco Claudio Olivas-Orozco Guadalupe Isela Ornelas-Paz José de Jesús Acosta-Muñiz Carlos Horacio 《植物病害和植物保护杂志》2023,130(1):143-155
Journal of Plant Diseases and Protection - Fire blight is a complex and devastating plant disease caused by the necrotrophic bacterium Erwinia amylovora. One of the main factors that determine the... 相似文献
50.
Valdelvira Rafael Garcia-Medina Guadalupe Crespo Jesus F. Cabanillas Beatriz 《Plant foods for human nutrition (Dordrecht, Netherlands)》2022,77(3):443-446
Plant Foods for Human Nutrition - There is growing interest in legumes such as lentil as healthy ingredients in gluten-free products. In that respect, foods based on lentils, like alimentary pasta,... 相似文献