Season has a Major Effect on the Essential oil Yield response to Nutrient Supply in Origanum Majorana     

Milagros Guerrero Trivino 《The Journal of Horticultural Science and Biotechnology》2013,88(5):520-527

Summary

The effect of different nutrients on growth and essential oil yield and composition in Origanum majorana L. were studied under two seasons differing mainly with respect to their temperature regimes. Oil composition was little affected by either season or nutrient regime. Growth rates and yield of essential oils were positively correlated with nutrient supply; less strongly so in the summer than in late spring. Speci®c oil yield (yield per unit plant weight) was generally positively correlated with nutrient level at the lower temperature, negatively at higher temperature. In both seasons, the oil yield per plant was closely correlated to the growth rate, regardless of the nutrient or dose, but the responses differed signi®cantly according to the season.  相似文献   

A qualitative investigation of adherence to nutritional therapy in malnourished adult AIDS patients in Kenya     

Dibari F  Bahwere P  Le Gall I  Guerrero S  Mwaniki D  Seal A 《Public health nutrition》2012,15(2):316-323

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Late Pleistocene ‐ Holocene palaeosols in the north of Sonora,Mexico: chronostratigraphy,pedogenesis and implications for environmental history     

T. Cruz‐y‐Cruz  S. Sedov  G. Sánchez  T. Pi‐Puig  K. Pustovoytov  H. Barceinas‐Cruz  B. Ortega‐Guerrero  E. Solleiro‐Rebolledo 《European Journal of Soil Science》2014,65(4):455-469

Red palaeosols of the late Pleistocene‐early Holocene, both buried and non‐buried, were studied recently in Sonora (NW Mexico) to reconstruct their pedogenesis as well as the palaeoenvironmental conditions. The alluvial palaeosol‐sedimentary sequence of the La Playa archaeological site is a key locality for the buried San Rafael palaeosol, which exhibits a 2Ah‐2Bw‐2BCk‐3Bgk profile and was defined as a Chromic Cambisol. Radiocarbon dates from pedogenic carbonates and charcoal set the soil formation interval between > 18 000 and 4300 calibrated years before present (cal. year BP). Micro‐morphological observations together with profile distribution of clay, carbonates, organic carbon, pedogenic iron oxides and rock magnetic properties indicated a strong eluvial‐illuvial redistribution of carbonates, moderate silicate weathering and gleying in the lower horizon. Although this soil was much more developed than the overlying syn‐sedimentary late Holocene Fluvisols, clay mineral composition and stable carbon isotope signatures of humus and carbonates were similar in both soils. We suggest that pedogenesis of the San Rafael palaeosol took place under a slightly more humid climate and relative geomorphic stability. This agrees with the regional palaeoclimate reconstruction, which indicates a moister climate during the Late Wisconsin glaciation (MIS 2). An abrupt termination of the San Rafael pedogenesis marked by disturbance and aridization features in the Ap horizon of the palaeosol could be linked to a global drought around 4200 years cal. year BP. Surface Chromic Cambisols in northern Sonora show similar pedogenetic characteristics to the buried red palaeosols of La Playa. They appear to be a relict component of the present day soil mantle.  相似文献   

The authors respond     

Tomás G. Guerrero Dr. med vet Diplomate ECVS  Mariano A. Makara Dr. med vet Diplomate ECVDI  Kristine Katiofsky Dr. med vet  Joe P. Morgan Prof. DVM Diplomate ACVR  Pierre M. Montavon Prof. Dr. med vet 《Veterinary surgery : VS》2011,40(5):643-643

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Early-successional vegetation changes after roadside prairie restoration modify processes related with soil functioning by changing microbial functional diversity     

Pablo García-Palacios  Matthew A. Bowker  Stephen J. Chapman  Santiago Soliveres  Antonio Gallardo  César Guerrero 《Soil biology & biochemistry》2011,43(6):1245-1253

Because of their rapidly changing vegetation dynamics and harsh environmental conditions, roadside prairies in semi-arid regions represent an exceptional study system in which to investigate the effects of plant-soil interactions on ecosystem functioning. We conducted a two-year field experiment on two roadside embankments in semi-arid central Spain differing in construction age to answer the following questions: (i) do commonly used restoration treatments (hydroseeding, fertilization and irrigation) affect soil microbial functional diversity and processes related to soil functioning (basal respiration, total N and P and in situ N availability rate)? (ii) what portion of plant effects on processes related to soil functioning is mediated indirectly by microbial functional diversity? Except for a small and negative irrigation effect on the microbial functional diversity in the three-year old site, the restoration treatments employed did not affect this variable. Fertilization increased plant diversity, an effect likely mediated by the enhanced soil nutrient availability with this treatment at early stages of secondary succession. In contrast, hydroseeding did not affect processes related to soil functioning. The total effect of the plant community on these processes was higher than that of the microbial functional diversity alone, suggesting that the studied slopes are to the greater extent regulated by plants. However, soil microbes are a key proximate influence in the system, as the indirect effects of plant community on soil functioning processes mediated by soil microbes represented 37-41% of the total plant effects observed. Our results indicate that the restoration of recently built slopes can potentially be improved with treatments that promote plant compositional shifts, such as fertilization, or alter soil function, such as the enhancement of soil microbial functional diversity. They also highlight that plant-soil interactions are an important process that can be manipulated for restoration purposes in early-successional stages, especially in nutrient-poor semi-arid ecosystems.  相似文献   

Nitrate uptake by Vicia faba L. Plants: A physiological approach 1     

Inmaculada Sánchez‐Guerrero  Juan M. Caba  Carmen Lluch  Francisco Ligero 《Journal of plant nutrition》2013,36(12):2589-2599

This study was conducted to obtain information on the properties of the nitrate (NO₃ ^‐) uptake system in Vicia faba. The results showed that in plants grown in the absence of NO₃ ^‐, they cannot absorb it upon initial exposure to this anion. When this plant makes contact with environmental NO₃ ^‐, NO₃ ^‐uptake by the roots is progressively induced. However, in NO₃ ^‐‐grown plants, the uptake system is yet induced so they had the ability to take up NO₃ ^‐ at high rates from the beginning. The Michaelis’ constant (K,_M) and maximum uptake rate (V_max) were estimated from measurements of NO₃ ^‐ depletion in the uptake medium. The apparent K_M value for net NO₃ ^‐ uptake in induced V. faba plants was 60 μM and the corresponding V_max 0.44 umol NO₃ ^‐ (g FW)^‐1 h^‐1. This last value was low compared with that of other species, while K_M is in the range for other higher plants. From the results of our experiments at low and high NO₃ ^‐ concentrations, we discuss the possibility of the existence of two NO₃ ^‐ uptake systems, one of a high affinity (functioning at low NO₃ ^‐concentrations) and another of low affinity (operative at high NO₃ ^‐ level in the medium).  相似文献   

Evidence that the negative relationship between seed mass and relative growth rate is not physiological but linked to species identity: a within-family analysis of Scots pine     

Castro J  Reich PB  Sánchez-Miranda A  Guerrero JD 《Tree physiology》2008,28(7):1077-1082

Seed mass and relative growth rate (RGR) are important determinants of early seedling growth, and hence seedling establishment. Although a positive interspecific relationship between seed mass and seedling dry mass is well established, much less is known about the relationships among seed mass, seedling mass and RGR within species. We examined relationships among seed mass, seedling mass and RGR within and among maternal plant lines of Scots pine (Pinus sylvestris L.). To assess the effects of seed mass and maternal origin on RGR, individual seeds from two seed crops (years 2004 and 2005) of ten maternal plants growing under nursery conditions were weighed and then germinated. Seed mass was strongly determined by maternal plant, and seedling mass was largely determined by seed mass, with a positive correlation between these variables both across and within maternal plants. In contrast, RGR was weakly related to seed mass, with no consistent pattern in the sign of the relationship. It is well known that species differ in RGR and that RGR is related to seed mass across species. Lack of consistent evidence for this relationship within maternal lines, and for Scots pine overall, suggests that the relationship is not directly causal, but reflects consistent evolutionary covariation in these two physiologically independent traits.  相似文献   

High pressure liquid chromatographic determination of polynuclear aromatic hydrocarbons in oysters.     

J P Hanus  H Guerrero  E R Biehl  C T Kenner 《Journal of the Association of Official Analytical Chemists》1979,62(1):29-35

A high pressure liquid chromatographic (HPLC) procedure is described for determining 13 polynuclear aromatic hydrocarbon (PNA) compounds in oysters at the 2 ppb level. These compounds are extracted from shellfish with acetonitrile and partitioned into petroleum ether; the petroleum ether is removed and the residue is saponified. The aromatic compounds are isolated by passing the saponifeid residue through silica gel and further purified and fractionated by muStyragel gel permeation chromatography. The in-ividual PNAs are then quantitatively determined by using a reverse phase HPLC column coupled to fluorescence, spectrophotometric, and 254 nm absorbance detectors in series. Recoveries from spiked samples generally were greater than 80%.  相似文献   

Beta-endorphin and cortisol concentrations in plasma of cattle     

FD SHAW  RK TUME 《Australian veterinary journal》1990,67(11):423-424

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Development of the cardiorespiratory system in dogs from days 16 to 46 of pregnancy          下载免费PDF全文

AA Martins  PO Favaron  L de Jesus Oliveira  BT Schäfer  FD Oliveira  MA Miglino 《Reproduction in domestic animals》2016,51(5):804-812

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