Effect of water and nutrient supply on root distribution in anEucalyptus globulus plantation     

António Fabião  Manuel Madeira  Eliel Steen 《Water, air, and soil pollution》1990,54(4):635-640

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   

Search for Resistance to Crenate Broomrape (<Emphasis Type="Italic">Orobanche crenata</Emphasis> Forsk.) in Pea Germplasm     

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   

Arsenic Contamination and Dispersion in the Engenho Inlet,Sepetiba Bay,SE, Brazil     

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   

Lettuce response to organic and phosphate fertilizers and root mycorrhization     

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   

Changes in porosity and microaggregation in clayey Ferralsols of the Brazilian Cerrado on clearing for pasture     

L. C.  Balbino    A. Bruand    M. Brossard    M. Grimaldi    M. Hajnos  & M. F.  Guimarães 《European Journal of Soil Science》2002,53(2):219-230

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Genetic relationships of Portuguese coles and other close relatedBrassica genotypes using nuclear RFLPs     

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   

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   

Heavy metal and PCB spatial distribution pattern in sediments within an urban catchment—contribution of historical pollution sources     

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

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Redistribution of 10B Absorbed by Leaves and Roots of Cashew Seedlings     

Regina Célia Faria Simão Canesin  Salatiér Buzetti  Juliana Aparecida de Souza 《Journal of plant nutrition》2015,38(4):639-646

Boron (B) is transported mainly in the xylem, but by using isotopic tracers it was possible to verify that B has significant mobility in the phloem of polyols-producing species. Thus, the objective of this study was to evaluate the mobility of ¹⁰B applied to cashew plants. The experiment was conducted from 05/10 to 07/10/2010 in a greenhouse of University of São Paulo State-UNESP, Ilha Solteira Campus, State of São Paulo, Brazil. 0.5 mg of B L^?1 of soil was used in the substrate. A solution of 255 mg of B L^?1 was used in recently mature and fully developed leaves. The total content of B and and percentage of boron in the plant derived from fertilizer (Bppf%) were evaluated in the old and new leaves stemming at 30 and 60 days after the application of ¹⁰B. As evidenced, B applied to leaves had restricted mobility in cashew tree. However, B applied in the substrate was absorbed and translocated to young leaves.  相似文献   

Risk assessment of dietary exposure to pesticides using a Bayesian method   总被引：2，自引：0，他引：2  

Paulo MJ  van der Voet H  Jansen MJ  ter Braak CJ  van Klaveren JD 《Pest management science》2005,61(8):759-766

Risk assessment of pesticides can be a statistically difficult problem because pesticides occur only occasionally, but they may occur on multiple components in the diet. A Bayesian statistical model is presented which incorporates multivariate modelling of food consumption and modelling of pesticide measurements which are for a large part below a measurement threshold. It is shown that Bayesian modelling is feasible for a limited number of food components, and that in a data-rich situation the model compares well with an empirical Monte Carlo modelling.  相似文献