The reproductive biology of okra. 2. Self-fertilization kinetics in the cultivated okra (Abelmoschus esculentus), and consequences for breeding     

Serge Hamon  Jean Koechlin 《Euphytica》1991,53(1):49-55

Summary The use of Cruden's index (1977), for studying okra sexual reproductive allocations, indicates a facultative autogamy mode. The purpose of the research described is to obtain more accurate information on the self-fertilization process. For this, self-pollen grain germination was stopped at different times of the day. Twelve varieties of Abelmoschus esculentus were used. Self-fertilization kinetics—expressed by the setting rate—displayed an increase between 7.00 to 16.00 hr. Study of obtained progenies, by stimulated allogamy, confirmed the process and showed that allo-pollen grains deposited on a stigma after midday had only a very little chance of contributing to fertilization. As a result, the polymorphism of the flower structure and particularly the distance between anther and stigmas, insect types and movement habits play major roles in governing okra allogamy. We also show that self-fertilization kinetics can be used to improve controlled hybrid production.  相似文献   

Long-term forest dynamic after land abandonment in a fire prone Mediterranean landscape (central Corsica,France)     

Florent?MouillotEmail author  Jean-Pierre?Ratte  Richard?Joffre  David?Mouillot  and ?Serge Rambal 《Landscape Ecology》2005,20(1):101-112

Two hundred years of landscape changes were studied on a 3,760 ha area of central Corsica (France) representing a typical Mediterranean environment. Different historical sources, including an accurate land-cover map from 1774 and statistics on land cover from 1848 and 1913, were used. Three additional maps (1960, 1975 and 1990) were drawn, and a complete fire history from 1957 to 1997 was created. Forests expanded slowly by a border effect. Forest expansion was more rapid in unburnt sites (0.59% per year) than in burnt sites (0.23% per year), mostly because the initial amount of forests was greater. Because of the border effect, the combination of past landscape pattern and short distance colonization abilities of forest species may have allowed the shrublands to persist in some places after land abandonment. This persistence may explain the pattern of fire in the landscape, since shrubland burn more readily than forests.  相似文献   

Determination of Mycoplasma bovis susceptibilities against six antimicrobial agents using the E test method     

Francoz D  Fortin M  Fecteau G  Messier S 《Veterinary microbiology》2005,105(1):57-64

The objective of this study was to determine the susceptibility of Mycoplasma bovis against six antibiotics using the E test methodology. Fifty-eight isolates of M. bovis originating from 55 affected cattle were evaluated. Specimen originated from: lung tissue, synovial fluid, tracheo-bronchial wash, milk, and external or inner ear discharge. Antimicrobial agents tested were azythromycin, clindamycin, erythromycin, enrofloxacin, spectinomycin and tetracycline. The E test strips were placed on the surface of Hayflick plates on which organism suspension was spread. Plates were incubated at 35 degrees C in a candle jar for 72 h. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip. M. bovis Donetta isolate was used as a control. All MICs were >256 microg/ml for erythromycin. MIC50 and MIC90 obtained for azythromycin were 3 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for tetracycline were 4 and 8 microg/ml, respectively. MIC50 and MIC90 obtained for spectinomycin were 2 and >1021 microg/ml, respectively. MIC50 and MIC90 obtained for clindamycin were 0.19 and >256 microg/ml, respectively. MIC50 and MIC90 obtained for enrofloxacin were 0.19 and 0.25 microg/ml, respectively. Resistance was not associated with the specimen source except for azythromycin. M. bovis susceptibilities were easily determined by the E test which demonstrated the efficacy of enrofloxacin and the acquired resistance to tetracycline, spectinomycin, azythromycin and clindamycin.  相似文献   

DNA testing for type III von Willebrand disease in Dutch Kooiker dogs     

van Oost BA  Versteeg SA  Slappendel RJ 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(3):282-288

Von Willebrand disease type III is widespread in Dutch Kooiker dogs. To eradicate von Willebrand disease from the breed, affected dogs and nonsymptomatic carriers must be excluded from breeding. Previous efforts to detect carriers in Kooiker dogs by a von Willebrand factor antigen assay were not satisfactory because of considerable overlap of plasma concentrations in normal dogs and carriers. The aim of this study was to develop and apply a DNA test for the detection of von Willebrand disease carriers in the Kooiker breed. Two mutations in the von Willebrand factor gene in affected Kooiker dogs have been described previously, a splice site mutation at the border of intron 16 and exon 16 and a missense mutation in exon 3. We have developed polymerase chain reaction tests for both mutations in genomic DNA. The missense mutation most likely is a neutral variant and appears to be a polymorphism present in many breeds. The allele-specific oligonucleotide test for the splice site mutation was applied in the selection of animals cleared to breed by the Dutch breeding club. In a few years, the mutation has been eliminated from the breeding stock without apparent increase of inbreeding or preferential sire usage.  相似文献   

Molecular typing of Mycoplasma agalactiae: tracing European-wide genetic diversity and an endemic clonal population     

Nouvel LX  Marenda MS  Glew MD  Sagné E  Giammarinaro P  Tardy F  Poumarat F  Rosengarten R  Citti C 《Comparative immunology, microbiology and infectious diseases》2012,35(5):487-496

Mycoplasma agalactiae causes chronic infections in small ruminants and remains endemic in many regions of the world, despite intensive and costly eradication programs. In this study, the innate genomic plasticity of M. agalactiae was exploited to design and assess a combination of molecular epidemiological tools to trace the pathogen in different geographic locations and to understand its emergence or re-emergence after eradication campaigns. For this purpose, two collections of M. agalactiae isolates, representing European outbreaks or localized endemic disease in a single region of France, were subjected to RFLP (Restriction Fragment Length Polymorphism) analyses using two sets of DNA probes (distributed across the genome and specific for the vpma gene locus), and a previously described VNTR (Variable Number Tandem Repeats) analysis. A combination of four genome-specific DNA probes and two VNTRs gave the highest discriminative power. Molecular typing revealed that, while isolates from diverse geographical origins fell into clearly different groups, the endemic disease repeatedly observed in the Western Pyrenees region over the past 30 years has been caused by a unique subtype of M. agalactiae. This indicates that the re-emergence of the pathogen after seemingly successful eradication programs is not due to the importation of exotic strains, but to the persistence of local reservoirs of infection.  相似文献   

Gas exchange and leaf aging in an evergreen oak: causes and consequences for leaf carbon balance and canopy respiration     

Rodríguez-Calcerrada J  Limousin JM  Martin-StPaul NK  Jaeger C  Rambal S 《Tree physiology》2012,32(4):464-477

Leaves of Mediterranean evergreens experience large variations in gas exchange rates over their life span due to aging and seasonally changing environmental conditions. Accounting for the changing respiratory physiology of leaves over time will help improve estimations of leaf and whole-plant carbon balances. Here we examined seasonal variations in light-saturated net CO(2) assimilation (A(max)), dark respiration (R(d)) and the proportional change in R(d) per 10 °C change in temperature (Q(10) of R(d)) in previous-year (PY) and current-year (CY) leaves of the broadleaved evergreen tree Quercus ilex L. A(max) and R(d) were lower in PY than in CY leaves. Differences in nitrogen between cohorts only partly explained such differences, and rates of A(max) and R(d) expressed per unit of leaf nitrogen were still significantly different between cohorts. The decline in A(max) in PY leaves did not result in the depletion of total non-structural carbohydrates, whose concentration was in fact higher in PY than CY leaves. Leaf-level carbon balance modeled from gas exchange data was positive at all ages. Q(10) of R(d) did not differ significantly between leaf cohorts; however, failure to account for distinct R(d) between cohorts misestimated canopy leaf respiration by 13% across dates when scaling up leaf measurements to the canopy. In conclusion, the decline in A(max) in old leaves that are close to or exceed their mean life span does not limit the availability of carbohydrates, which are probably needed to sustain new growth, as well as R(d) and nutrient resorption during senescence. Accounting for leaf age as a source of variation of R(d) improves the estimation of foliar respiratory carbon release at the stand scale.  相似文献   

Partial substitution of fish meal with soybean and cottonseed meals in diets for African bonytongue,Heterotis niloticus (Cuvier, 1829) fingerlings: effects on growth,feed efficiency and body composition     

Serge‐Eric Monentcham  Jean Kouam  Didier Chuba  Bernard Wathelet  Victor Pouomogne  Patrick Kestemont 《Aquaculture Research》2010,41(10):e385-e392

A feeding trial was conducted to examine the suitability of soybean meal (SBM) and cottonseed meal (CSM) as a partial substitute for the dietary protein supplied by fish meal for H. niloticus fingerlings. Fish were fed with four isonitrogenous (350 g kg^?1 crude protein) and isoenergetic (18.8 kJ g^?1 GE) diets in which fish meal protein was gradually replaced by plant protein from a mixture of SBM and CSM (0%, 25%, 50% and 75% in diets 1, 2, 3 and 4 respectively). Triplicate groups of fingerlings H. niloticus (mean weight of 5 g) were handfed twice daily to apparent satiation for 60 days inside net hapas. Growth performances (SGR varied from 3.09% to 3.16% day^?1) of fingerlings fed diets containing 0%, 25% and 50% plant protein were not significantly different (P>0.05). At 75% fish meal substitution, growth and feed utilization efficiency indicators were significantly reduced (P<0.05). The carcass composition were also significantly (P<0.05) affected by the replacement level of fish meal, except dry matter and ash. Results suggest that the dietary fish meal protein could efficiently be substituted by a mixture of soybean and cottonseed meals up to 50%, without adverse effects on maximal growth in practical diets for H. niloticus fingerlings.  相似文献   

Improvement of cropping systems by integration of rice breeding: a novel genetic improvement strategy     

Michel Vales  Lucien Séguy  Serge Bouzinac  James Taillebois 《Euphytica》2009,167(2):161-164

Rice improvement is based to an increasing extent on ever-sharper genetic analysis to the detriment of classical breeding, which is disappearing. Analytical genetics are very promising, but they cannot replace integrated and finalized breeding. Little attention has been paid to improving participatory rice breeding methods for subsequent integration into sustainable cropping systems. Special methodological initiatives are required to ensure the success of this breeding-agronomy integration. This integration of inexpensive breeding methods has increased the biodiversity of rice: low temperature and drought tolerant upland rice varieties for mountain areas, and polyvalent varieties, which have the ability to grow in both rainfed or irrigated conditions, they are perfectly adapted to improved cropping systems and to beneficiaries’ needs and preferences. These preliminary results on this integration demonstrate that the present approach is relevant.  相似文献   

Effects of plant morphological traits on phoma black stem in sunflower     

André Aguiar Schwanck  Serge Savary  Philippe Debaeke  Patrick Vincourt  Laetitia Willocquet 《European journal of plant pathology / European Foundation for Plant Pathology》2016,144(2):345-360

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Effects of logging on orangutan behavior     

Madeleine E. Hardus  Adriano R. Lameira  Steph B.J. Menken  Serge A. Wich 《Biological conservation》2012,146(1):177-187

The human footprint is increasing across the world’s natural habitats, causing large negative impacts on the survival of many species. In order to successfully mitigate the negative effects on species’ survival, it is crucial to understand their responses to human-induced changes. This paper examines the effect of one such disturbance, logging, on Sumatran orangutans – a critically endangered great ape. Orangutan population densities may decrease or remain stable after logging, but data on the effects of logging on the behavior of individuals is scant. Here, we provide individual-level behavioral data based on direct observations in 2003–2008 at the Ketambe (Sumatra, Indonesia) research area (partly subject to intense selective logging) in order to assess responses of Sumatran orangutans to logging. Logging significantly negatively affected forest structure and orangutan food resources, specifically important fallback and liana-derived foods. Individual orangutans behaved differently between logged and pristine forest; they moved more and rested less in logged forest. With the exception of figs, diet composition remained overall similar. Altogether, life after logging seems energetically more expensive for orangutans. Based on the results of this study, we provide recommendations for conservation research and guidelines for reduced-impact logging.  相似文献