Comparison of P and cation cycling in two contrasting seasonally dry forest ecosystems     

Julio Campo  Juan F. Gallardo 《Annals of Forest Science》2012,69(8):887-894

Context

Interactions of N and P cycles and those of other macro-elements in forests are scarcely known.

Aim

This study compares the P cycle in two very different forest ecosystems where soil P availability is low (tropical dry forest in Mexico and Mediterranean forest in Spain) in relation to Ca, K, and Mg cycles.

Methods

Compiled data belonging to these two forest sites are discussed, comparing the P and base cation budgets and exploring relationships among P and base cation cycles.

Results

Broad differences between input and output of base cations were observed. Analysis of the P budget indicates P retention inside both forest ecosystems. The tropical dry forest has higher nutrient contents than those found in the Mediterranean temperate forest. Chemical composition of forest leaves and litters, and base cation?CP ratios varied according to soil P availability and cation concentrations. However, P resorption is higher in the tropical dry forest than in the temperate one.

Conclusion

This study reveals the existence of P retention at the ecosystem level in both forests, but suggested P limitation at the Mediterranean forest seems to be stronger than that occurring at the tropical forest.  相似文献   

Influence of lipids in the generation of phenylacetaldehyde in wort-related model systems     

Gallardo E  De Schutter DP  Zamora R  Derdelinckx G  Delvaux FR  Hidalgo FJ 《Journal of agricultural and food chemistry》2008,56(9):3155-3159

The effect of lipids on the formation of the Strecker aldehyde phenylacetaldehyde during wort boiling was studied to determine the role that small changes in the lipid content of the wort have in the production of significant flavor compounds in beer. Wort was treated with 0-2.77 mmol per liter of glucose, linoleic acid, or 2,4-decadienal and heated at 60-98 degrees C for 1 h. After this time, the amount of the Strecker aldehyde phenylacetaldehyde increased in the samples treated with linoleic acid or decadienal but not in the samples treated with glucose. Thus, the amount of phenylacetaldehyde produced in the presence of linoleic acid was 1.1-2.5 times the amount of the Strecker aldehyde produced in the control wort, and this amount increased to 3.6-4.6 times when decadienal was employed. The higher reactivity of decadienal than linoleic acid for this reaction decreased with temperature and was related to the oxidation of linoleic acid that occurred to a higher extent at higher temperatures. The above results suggest that lipids can contribute to the formation of Strecker aldehydes during wort boiling and that changes in the lipid content of the wort will produce significant changes in the formation of Strecker aldehydes in addition to other well-known consequences in beer quality and yeast metabolism. On the other hand, because of the high glucose content in wort, small changes in its content are not expected to affect the amount of Strecker aldehydes produced.  相似文献   

Plasma leptin levels in pigs with different leptin and leptin receptor genotypes     

M Amills  D Villalba  M Tor  A Mercadé  D Gallardo  B Cabrera  N Jiménez  J L Noguera  A Sànchez  J Estany 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2008,125(4):228-233

A C3469T mutation at exon 3 of the pig leptin (Lep) gene has been genotyped in diverse pig breeds yielding controversial results with regard to its association with growth, fatness and carcass traits. A similar situation has been reported for a HpaII restriction fragment length polymorphism (RFLP) in the pig leptin receptor (Lepr) gene, where associations were found depending on the statistical model employed. The main objective of our work was to investigate if leptin plasma concentrations differ in pigs with different C3469T and Lepr HpaII RFLP genotypes. With this aim, we have measured plasma leptin levels at 160 days in 68 Landrace pigs with different Lep C3469T and Lepr HpaII RFLP genotypes. Neither Lep (TT: 11.68 ng/ml, TC: 10.71 ng/ml) nor Lepr (AA: 12.6 ng/ml, AB: 10.93 ng/ml, BB: 11.74 ng/ml) genotypes influenced significantly plasma Lep concentration. Moreover, we did not find any association between Lep and Lepr genotypes and phenotypic variation at growth and fatness traits in a commercial population of 320 Landrace pigs.  相似文献   

Effect of diet and type of pregnancy on plasma metabolic response in sheep and its further effect on lamb performance     

Carcamo  J. G.  Arias-Darraz  L.  Alvear  C.  Williams  P.  Gallardo  M. A. 《Tropical animal health and production》2019,51(7):1943-1952

This trial evaluated the individual and interactional effects of diet and type of pregnancy (twin or single) on plasma metabolic response in ewes and their lambs from late pre-partum to late post-partum. Thus, a flock of 18 Ile de France breed sheep, consisting of 8 twin-bearing and 10 single-bearing ewes, were allocated to one of two groups according to their diet, either based on ad libitum naturalized pasture hay (NPH) or red clover hay (RCH), from d 45 pre-partum to d 60 post-partum. Plasma samples were collected at different times to determine albumin, cholesterol, total protein and urea, plus glucose and β-hydroxybutyrate (BHB) concentration in ewes. The data was processed using the lme4 package for R, and SPSS Statistics 23.0 for Windows. The results showed that both diet and type of pregnancy influenced the metabolic profile in ewes, showing an inverse relationship between single- and twin-bearing ewes regarding glucose and especially BHB proportions from pre-partum to birth. During post-partum, higher urea concentrations were observed in twin- and single-bearing ewes fed RCH in contrast to those fed NPH, as a result of the higher-quality forage offered to ewes. Regarding lambs, the diet and type of pregnancy influenced the total protein and urea levels, where an inverse relationship at birth and early post-partum between albumin and cholesterol vs. total protein and urea was detected, reflecting a trend (P value between 0.06 and 0.07) to a better performance by groups of single lambs, especially those from single-bearing ewes fed RCH. Finally, under the conditions of this study, the maternal diet and type of pregnancy influenced the plasma metabolic response in ewes and their lambs, affecting the lamb performance especially at birth.

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Karyotype analysis of interspecific hybrids between Haliotis rufescens and Haliotis discus HANNAI     

Gabriel Amar‐Basulto  Fabiola Lafarga‐De la Cruz  Patricia Iturra‐Constant  Cristian Gallardo‐Escárate 《Aquaculture Research》2011,42(10):1460-1466

Evidence of hybridization in Haliotis has been mainly supported by hatchery experiences and collection of wild hybrid abalones among several species from natural populations worldwide. However, despite the importance to understand the role of the hybridization process through Haliotidae evolution, and also its impact on the abalone aquaculture, genetic studies in hybrid abalones have been poorly developed. Herein, cytogenetic approach allows studying the genetic conformation in hybrid organisms at the chromosome level. This paper reports a quantitative karyotype analysis in Haliotis rufescens, Haliotis discus hannai and their interspecific hybrid. Thus, to characterize chromosome pairs and establish cytogenetic comparisons, chromosome banding with distamycin‐A/4,6‐diamidino‐2‐phenylindole fluorochromes and morphologic measurements were performed. The results showed that the hybrids are successfully viable and their karyotypes evidenced a conservative chromosome number of 2n=36. The karyo‐idiogram showed a high correspondence in chromosome pair morphology among the hybrids and their parental species, except for a single heteromorphic pair that corresponds to the chromosome 16 from H. rufescens andH. d. hannai respectively. The implications of the abalone hybrid viability derived from its chromosome composition are discussed.  相似文献   

Measurement and estimation of plastic greenhouse reference evapotranspiration in a Mediterranean climate   总被引：2，自引：0，他引：2  

M. D. Fernández  S. Bonachela  F. Orgaz  R. Thompson  J. C. López  M. R. Granados  M. Gallardo  E. Fereres 《Irrigation Science》2010,28(6):497-509

The standard FAO methodology for the determination of crop water requirements uses the product of reference evapotranspiration (ET_o) and crop coefficient values. This methodology can be also applied to soil-grown plastic greenhouse crops, which occupy extended areas in the Mediterranean basin, but there are few data assessing methodologies for estimating ET_o in plastic greenhouses. Free-drainage lysimeters were used between 1993 and 2004 to measure ET_o inside a plastic greenhouse with a perennial grass in Almería, south-eastern Spain. Mean daily measured greenhouse ET_o ranged from values slightly less than 1 mm day⁻¹ during winter to values of approximately 4 mm day⁻¹ during summer in July. When the greenhouse surface was whitened from March to September (a common practice to control temperature), measured ET_o was reduced by an average of 21.4%. Different methodologies to calculate ET_o were checked against the measurements in the greenhouse without and with whitening. The methods that performed best in terms of accuracy and statistics were: FAO56 Penman–Monteith with a fixed aerodynamic resistance of 150 s m⁻¹, FAO24 Pan Evaporation with a constant Kp of 0.79, a locally-calibrated radiation method and Hargreaves. Given the data requirements of the different methods, the Hargreaves and the radiation methods are recommended for the calculation of greenhouse ET_o because of their simplicity.  相似文献   

First report of the reduction in treatment efficacy of the organophosphate azamethiphos against the sea lice Caligus rogercresseyi (Boxshall & Bravo, 2000)     

Gabriel Arriagada  Jorge Figueroa  Sandra L. Marín  Ana María Arriagada  Marcela Lara  Cristian Gallardo‐Escrate 《Aquaculture Research》2020,51(1):436-439

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Changes in net N mineralization rates and soil N and P pools in a pine forest wildfire chronosequence     

Jorge Durán  Alexandra Rodríguez  José María Fernández-Palacios  Antonio Gallardo 《Biology and Fertility of Soils》2009,45(7):781-788

The concern that climate change may increase fire frequency and intensity has recently heightened the interest in the effects of wildfires on ecosystem functioning. Although short-term fire effects on forest soils are well known, less information can be found on the long-term effects of wildfires on soil fertility. Our objective was to study the 17-year effect of wildfires on forest net mineralization rates and extractable inorganic nitrogen (N) and phosphorus (P) concentrations. We hypothesize that (1) burned forest stands should exhibit lower net mineralization rates than unburned ones; (2) these differences would be greatest during the growing season; (3) differences between soil variables might also be observed among plots from different years since the last fire; and (4) due to fire-resistant geochemical processes controlling P availability, this nutrient should recover faster than N. We used a wildfire chronosequence of natural and unmanaged Pinus canariensis forests in La Palma Island (Canary Islands). Soil samples were collected during winter and spring at 22 burned and unburned plots. We found significantly higher values for net N mineralization and extractable N pools in unburned plots. These differences were higher for the winter sampling date than for the spring sampling date. Unlike extractable N and N mineralization rates, extractable P levels of burned plots exhibited a gradual recovery over time after an initial decrease. These results demonstrate that P. canariensis forest soils showed low resilience after wildfires, especially for N, and that this disturbance might induce long-term changes in ecosystem functioning.  相似文献   

Changes in the spatial structure of oak carbon-based secondary compounds after pine harvesting     

Felisa Covelo  Antonio Gallardo 《Forest Ecology and Management》2009,258(11):2511-2518

In natural plant populations, leaf polyphenols show high intraspecific variation that occurs both temporally and spatially. Leaf phenolics may be induced by diverse ecological factors such as light, nitrogen availability or herbivory attack. Both light and nitrogen availability can show spatial structure in forested stands, meaning that they each have a high degree of autocorrelation, which can determine the appearance of spatial structure in leaf polyphenols. However, the availability of these resources may be drastically changed by forest disturbance, and little is known about the effect of forest disturbance on the spatial pattern and scale of leaf secondary compounds. We hypothesise that the spatial structure of leaf polyphenols in understory vegetation will disappear due to forest harvesting, because these compounds depend on light availability, yet it will remain unaltered for those compounds that either depend on the availability of other resources or are under major genetic control. The study was performed in young pedunculate oak (Quercus robur) populations growing either under a pine canopy (Pinus pinaster) stand or in a pine harvested stand in NW Spain. The spatial structures of green and senescent leaf polyphenols, tannins, non-tannin polyphenols and nitrogen were analysed in both stands using geostatistical analysis. The spatial structures observed for green and senescent leaf polyphenols and tannins in the forested stand disappeared in the harvested stand. However, non-tannin polyphenols, as well as nitrogen, showed spatial structure in both stands. Understanding these changes may be important for the successful recovery of native oak populations growing under pine forests in NW Spain, one of the priorities of the local government. Our results showed that changes in the concentration of leaf secondary compounds after disturbance may be accompanied by differences in their spatial properties, which may have important consequences for ecosystem function.  相似文献   

Degradability of soils under oak and pine in Central Spain     

Elena Charro  J. F. Gallardo  A. Moyano 《European Journal of Forest Research》2010,129(1):83-91

The purpose of this research was to study the influence of the vegetation on the soil C pool of forests of pines (Pinus sylvestris) and oaks (Quercus pyrenaica), located in Central-Western Spain. Horizons from selected soils located in these forests were sampled, and the soil organic C (SOC) was determined. In addition, in vitro incubation experiments were carried out, under controlled conditions, to monitor the stability of SOC against the microbial activity. Soil humus fractions were isolated following a classical procedure of chemical fractionation using alkaline solutions, before and after the incubation experiment. A deeper O horizon was found under the pine forest than under oak one; however, higher SOC content was found in the oak site than that under pine one. During the in vitro mineralization process, a lower CO₂ production by the soil sample from pine forest was observed, in relation to that emitted by the oak soil. In addition, a lower humification degree was estimated for the soil humus under pines than for that under oaks. In conclusion, replacement of oaks by pines produced a decrease in SOC accumulation and a lower quality of humus in the forest soils.  相似文献