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71.
Mercedes Uscola Juan A. Oliet Pedro Villar-Salvador Eugenio Díaz-Pinés Douglass F. Jacobs 《European Journal of Forest Research》2014,133(2):235-246
Most studies examining inorganic N form effects on growth and nutrition of forest trees have been conducted on single species from boreal or temperate environments, while comparative studies with species from other biomes are scarce. We evaluated the response of two Mediterranean trees of contrasting ecology, Quercus ilex L. and Pinus halepensis Mill., to cultivation with distinct inorganic N forms. Seedlings were fertilized with different NH4 +/NO3 ? proportion at either 1 or 10 mM N. In both species, N forms had small effects at low N concentration, but at high N concentration they markedly affected the plant performance. A greater proportion of NH4 + in the fertilizer at high N caused toxicity as it reduced growth and caused seedling death, with the effect being greater in Q. ilex than in P. halepensis. An increase in the proportion of NO3 ? at high N strongly enhanced growth relative to low N plants in P. halepensis but had minor effects in Q. ilex. Relatively more NH4 + in the fertilizer enhanced plant P concentration but reduced K concentration in both species, while the opposite effect occurred with NO3 ?, and these effects were enhanced under high N concentration. We conclude that species responses to inorganic N forms were related to their ecology. P. halepensis, a pioneer tree, had improved performance with NO3 ? at high N concentration and showed strong plasticity to changes in N supply. Q. ilex, a late successional tree, had low responsiveness to N form or concentration. 相似文献
72.
The life cycle of cuttlefish fed ad libitum exclusively on live grass shrimp (Palaemonetes varians) was studied during 5 consecutive generations. Different culture temperatures promoted different (P < 0.05) exponential growth for each life cycle, being summer generations shorter than those of winter. Higher temperatures promoted higher IGR’s and mortality, while lower temperatures promoted increased life span, reproduction stages, total fecundity and total egg biomass. Increased generations also seemed to increase fertility. A “hybrid” generation promoted the best results in terms of hatchling weight, individual fecundity and fertility. Mean egg weight was related to female size and embryonic development took longer at lower temperatures. Brood stock sex ratios seemed to be temperature related. All of these culture aspects were also compared between themselves in order to establish future brood stock methodologies. Grass shrimp proved to be a good diet for the culture of cuttlefish throughout the life cycle. The use of only one species reduces costs and labor associated to cuttlefish culture. 相似文献
73.
Pedro M. Domingues Philip E. Turk Jose P. Andrade Phillip G. Lee 《Aquaculture International》1998,6(5):387-402
Studies were conducted to determine the potential for large scale culture of the mysid shrimp Mysidopsis almyra. Reproduction was consistent, as newly hatched mysids were always present in the culture trays. At the end of 45 day preliminary trials, the populations in the culture trays had increased 323.3% and 256.6%. A larger pilot-scale system connected to a biological filtration tank was constructed and operated for 17 weeks. Two rectangular trays (125 cm × 50 cm × 8 cm deep) were placed one above the other; water volume in each tray was 20 l. The room was kept dark. Temperatures were maintained at 26(2) °C and salinities at 20(2). A total of 1,000 adult mysids were placed in the culture tray and the hatchlings were collected and moved into a hatchling tray. Water circulation was static except for twice-daily water exchanges; newly hatched Artemia nauplii (24 h incubation) were fed to the mysids immediately after each water exchange. Feeding presented no technical problem to the pilot-scale culture of mysids in static water systems but the cost of Artemia did represent the largest expense. Mean (SD) mysid production throughout the 17 weeks of the trial was 133(69) hatchlings d–1 with highest production [244(30) hatchlings d–1] occurring between weeks 11 and 13. Mean survival in the hatchling tray after the 14 day growth periods was 41.4%. Reproduction occurred at ammonia-nitrogen and nitrite-nitrogen concentrations as high as 1.5 mg l–1 and 0.250 mg l–1 respectively, and at pH values as low as 7.6. When pH decreased to 7.38, reproduction halted abruptly and mortality increased sharply. © Rapid Science Ltd. 1998 相似文献
74.
Jose M Carral Jesús D Celada Maria Sáez-Royuela Ruth Rodríguez Amelia Aguilera & Pedro Melendre 《Aquaculture Research》2006,37(6):632-636
Four desticking procedures for tench eggs (A: tannic acid solution (1 g L−1) for 15 s; B: alcalase enzyme solution (8 mL L−1) for 60 s; C: alcalase enzyme solution (15 mL L−1) for 120 s; D: Woynarovich and Woynarovich (1980) solution for 58 min followed by tannic acid solution (1 g L−1) for 15 s) were tested to obtain data about influence on embryo survival to hatching stage and further survival and growth of the larvae. In the tannic acid and Woynarovich and Woynarovich (1980) treatment (A and D) few eggs stuck together and some were adhered to the incubator walls, whereas in the alcalase treatments (B and C) eggs neither stuck together nor adhered to the incubator walls. Percentages of hatched larvae did not show significant differences (mean values ranged between 47.4% in treatment A to 37.0% in treatment C). Larvae deformities observed were <0.5% in all cases. There were no significant differences among survival and growth rates of the larvae from different egg desticking origin, reaching, after 30 days, mean survival values around 90% and total length and weight of 12.5 mm and 19 mg respectively. 相似文献
75.
Concepts and methods for landscape multifunctionality and a unifying framework based on ecosystem services 总被引:2,自引:0,他引:2
Matias E. Mastrangelo Federico Weyland Sebastian H. Villarino María P. Barral Laura Nahuelhual Pedro Laterra 《Landscape Ecology》2014,29(2):345-358
The potential of landscapes to supply multiple benefits to society beyond commodities production has received increasing research and policy attention. Linking the concept of multifunctionality with the ecosystem services (ES) approach offers a promising avenue for producing scientific evidence to inform landscape planning, e.g., about the relative utility of land-sharing and land-sparing. However, the value for decision-making of ES-based multifunctionality assessments has been constrained by a significant conceptual and methodological dispersion. To contribute towards a cohesive framework for landscape multifunctionality, we analyse case studies of joint ES supply regarding ten criteria designed to ultimately answer four aspects: (i) the multifunctionality of what (e.g., landscapes), (ii) the type of multifunctionality (e.g., based on ES synergies), (iii) the procedure of multifunctionality assessments, and (iv) the purpose of multifunctionality. We constructed a typology of methodological approaches based on scores for criteria describing the evaluation method and the level of stakeholder participation in assessments of joint ES supply. Surveyed studies and underlying types of methodological approaches (spatial, socio-spatial, functional, spatio-functional) differed in most criteria. We illustrate the influence of methodological divergence on planning recommendations by comparing two studies employing contrasting approaches (spatial and functional) to assess the joint supply of wildlife habitat and agricultural production in the Argentine Chaco. We distinguish between a pattern-based and process-based multifunctionality, where the latter can only be detected through approaches considering the ecological processes (e.g., ES complementarities) supporting the supply of multiple ES (functional and spatio-functional). Finally, we propose an integrated approach for assessing a socially-relevant process-based multifunctionality. 相似文献
76.
Francisco Javier Estay Rodrigo Noriega Jose Pedro Ureta Werner Martín & Nelson Colihueque 《Aquaculture Research》2004,35(5):447-452
Data on reproductive traits in a cultured population of brown trout (Salmo trutta L.) in southern Chile were collected over three consecutive reproductive seasons: 1999, 2000 and 2001, corresponding to the first (at 3 years), second and third spawnings in females. Data were collected from individual females (n=238, 273 and 169 respectively). The reproductive season lasted mainly from June to August. The peak (July) tended to increase with each season (55.46%, 62.27% and 80.81% of total spawning fish respectively). Female body weight (470.8±102.5, 735.0±150 and 1263.9±263.4 g), total fecundity (1182±344, 1904±595 and 2744±605) and egg diameter (4.64±0.11, 4.67±0.27 and 5.24±0.12 mm) increased significantly (P<0.01) over successive reproductive seasons, particularly between the second and third spawnings. Relative fecundity, on the other hand, decreased significantly with each season (3577±471, 2591±900 and 2181±360). Following analysis of the variables over the three seasons, the correlation pattern of female body weight with total fecundity (r=0.91, n=458; P<0.001) and relative fecundity (r=?034, n=451; P<0.001) proved similar to that described in other salmonid females. Fertilization rate and survival to the eyed egg stage were also positively correlated (r=0.73, n=453; P<0.001). The systematically high values obtained for these latter variables over the seasons evaluated (consistently above 90%) are clearly greater than those we registered in other species of salmonids bred in Chile under similar conditions and suggest highly efficient biological variables that determine the gamete fertilization of this species. The brown trout is, therefore, an interesting potential aquaculture resource in Chile. 相似文献
77.
Multidrug-resistant (MDR) Escherichia coli, mainly extraintestinal pathogenic E. coli (ExPEC), has been widely reported in infections worldwide. In agricultural soils, manure is a hotspot for the dissemination of antimicrobial resistance genes (ARGs) and pathogenic bacteria; however, MDR bacteria have also been reported in soils with no history of manure use. In addition, cross-resistance and co-resistance have been described as responsible for the metal-driven selection of bacteria resistant to antimicrobials. Therefore, the aim of this study was to analyze three MDR E. coli isolates obtained from Brazilian grain culture soil samples with no history of manure use by whole-genome sequencing. The MDR E. coli isolates were recovered from soils from corn and coffee fields, and presented resistance to β-lactams, quinolones, aminoglycosides, tetracyclines, sulphonamides, and dihydrofolate reductase inhibitor. Resistome analysis showed ARGs to several antimicrobials (i.e., β-lactams, tetracyclines, aminoglycosides, sulphonamides, trimethoprim, phenicols, fosfomycin, and macrolides) as well as several metal resistance genes and antibacterial biocide resistance genes. In addition, known mutations in quinolone-resistance-determining regions of GyrA (Ser83Leu and Asp87Asn), ParE (Ser458Thr), and ParC (Ser80Ile) were also detected. Virulome analysis showed the presence of virulence genes (lpfA, mcmA, gad, mchF, iroN, cma, and iss) associated with ExPEC. Multidrug-resistant ExPEC isolates were assigned to phylogenetic group B1. The presence of MDR B1-ExPEC in soil samples shows the ability of these isolates to survive in soils. This study reports for the first time some sequence types (i.e., ST345, ST448, and ST1146) of MDR E. coli in Brazilian soils. Therefore, these findings contribute to the monitoring of antimicrobial resistance and surveillance studies based on whole-genome sequencing worldwide. 相似文献
78.
Carvalho Thayslan Brosinsky Arlena Foerster Saskia Teixeira Adunias Medeiros Pedro 《Journal of Soils and Sediments》2022,22(9):2557-2577
Journal of Soils and Sediments - Soil erosion by water yields sediment to surface reservoirs, reducing their storage capacities, changing their geometry, and degrading water quality. Sediment... 相似文献
79.
Karim Sorkheh Behrouz Shiran T. M. Gradziel B. K. Epperson Pedro Martínez-Gómez E. Asadi 《Euphytica》2007,156(3):327-344
Amplified fragment length polymorphism (AFLP) analysis is a rapid and efficient method for producing DNA fingerprints and
molecular characterization. Our objectives were to: estimate genetic similarities (GS), marker indices, and polymorphic information
contents (PICs) for AFLP markers in almond cultivars; assess the genetic diversity of almond cultivars and wild species, using
GS estimated from AFLP fingerprints and molecular characterization; and facilitate the use of markers in inter-specific introgression
and cultivar improvement. The genetic diversity of 45 almond cultivars from Iran, Europe, and America, were studied assaying
19 primer combinations. In addition, several agronomic traits were evaluated, including flowering and maturity times, self-incompatibility,
and kernel and fruit properties. Out of the 813 polymerase chain reaction fragments that were scored, 781 (96.23%) were polymorphic.
GS ranged from 0.5 to 0.96, marker indices ranged from 51.37 to 78.79, and PICs ranged from 0.56 to 0.86. Results allowed
the unique molecular identification of all assayed genotypes. However, the correlation between genetic similarity clustering
as based on AFLP and clustering for agronomic traits was low. Cluster analysis based on AFLP data clearly differentiated the
genotypes and wild species according to their origin and pedigree, whereas, cluster analysis based on agronomic data differentiated
according the pomological characterization. Our results showed the great genetic diversity of the almond cultivars and their
interest for almond breeding. 相似文献
80.
André M. Almeida Anabela B. Silva Susana S. Araújo Luís A. Cardoso Dulce M. Santos José M. Torné Jorge M. Silva Matthew J. Paul Pedro S. Fevereiro 《Euphytica》2007,154(1-2):113-126
We have previously obtained several lines of tobacco transformed with a trehalose-6-phosphate synthase gene of plant origin
(Arabidopsis thaliana), involved in the first step of the biosynthesis of trehalose, a known osmoprotectant. Two showed distinct intensity of expression:
high (B5H) and low (B1F). Such lines were analyzed for trehalose-6-phosphate content and the obtained results demonstrated
to be in accordance with the expression results. In order to study the responses of photosynthesis to water deficit of transgenic
lines in comparison to wild type (WT), three experiments were performed under different conditions: (1) Relative water (2)
Leaf gas exchange (3) Modulated Chlorophyll a Fluorescence. Different responses in RWC of plant lines to water withdrawal were detected, with transgenic line B5H indicating
less water loss after the water withdrawal period. Similar responses to water deficit regarding the leaf gas exchanges were
recorded for the three lines. When subjected to water deficit stress situations, higher F
v/F
m, ΦPSII and qP were detected for the transgenic lines. Under a SWC of 20% where higher values for such parameters were detected with
special relevance for the B5H line, indicating a possible higher ability to withstand severe drought stress and to resist
to prolonged periods without water than the B1F and WT lines. 相似文献