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1.
The distribution of tylosin was studied using a crossover design, in six pigs following i.v. and i.m. administration of 10 mgkg(-1) b.w. Plasma samples were analysed by HPLC and UV absorbance detection. After i.v. administration, t(1/2beta) was 271.3 min, V(d) 14.6 Lkg(-1), V(ss) 9.7 Lkg(-1) and CL 26.8 mLmin(-1)kg(-1). After i.m. administration, a C(max) of 1 microgmL(-1) was reached at 90 min. Mean absorption time was 1988.7 min and bioavailability was 95%. 相似文献
2.
Accumulation of soluble phenolic compounds in sunflower capitula correlates with resistance to Sclerotinia sclerotiorum 总被引：2，自引：0，他引：2
Disease symptoms and total soluble phenolics content have been analysed in four sunflower (Helianthus annuus L.)lines with different resistance levels(from highly susceptible to resistant) to head rot caused by Sclerotinia sclerotiorum (Lib.) de Bary. At the beginning of the flowering stage, capitula were inoculated by spraying with a water suspension of
ascospores, and disease symptoms were evaluated from day 6 to day14 after inoculation. The most susceptible genotypes showed
all their ovaries to be necrosed and abundant lesions in corollas, bracts and receptacle. In the resistant line, the ovary
and corolla were only partially necrosed with no symptoms in the bracts or the receptacle. Total soluble phenolics were extracted
and quantified from different parts of the capitulum in both inoculated and non-inoculated plants. The amount of phenolic
compounds depended on the sunflower line, the time after inoculation, and the tissue. Higher constitutive and induced phenolic
content as well as phenylalanine ammonia-lyase activity were present in the most resistant line, these differences correlated
with the absence/presence of disease symptoms.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Gamboa-Badilla Nancy Segura Alfonso Bagaria Guillem Basnou Corina Pino Joan 《Landscape Ecology》2020,35(12):2745-2757
Context
It is known that land-use and land-cover (LULC) changes affect plant community assembly for decades. However, both the short- and the long-term effects of contrasting LULC change pathways on this assembly are seldom explored.
ObjectivesTo assess how LULC change pathways affect woody plant community parameters (i.e. species richness, diversity and evenness) and species’ presence and abundance, compared with environmental factors and neutral processes.
MethodsThe study was performed in Mediterranean limestone scrublands in NE Spain. Cover of each woody species was recorded in 150 scrubland plots belonging to five LULC change pathways along the past century, identified using land-cover maps and fieldwork. For each plot, total woody and herbaceous vegetation cover, local environmental variables and geographical position were recorded. Effects of these pathways and factors on plant community parameters and on species presence and abundance were assessed, considering spatial effects potentially associated to neutral processes.
ResultsSpecies richness and diversity were associated with LULC change pathways and elevation, while evenness was only associated with this last. Pathways and environmental variables explained similar variance in both species’ presence and cover. In general, while community parameters were affected by recent-past (1956) use, species presence and abundance were associated with far-past (pre-1900) cropping. No relevant spatial effect was detected for any studied factor.
ConclusionsHistorical LULC changes and current environmental factors drive local-scale community assembly in Mediterranean scrublands to an equal extent, while contrasting time-scale effects are found at community and species level. Neutral, dispersal-based processes are found to be non-relevant.
相似文献4.
ABSTRACT Effects of phenylpropanoid and energetic metabolism inhibition on resistance were studied during appropriate host and nonhost cereal-rust interactions. In the appropriate barley-Puccinia hordei interaction, phenylalanine ammonia lyase (PAL) and cinnamyl alcohol dehydrogenase (CAD) inhibition reduced penetration resistance in two genotypes, suggesting a role for phenolics and lignins in resistance. Interestingly, penetration resistance of the barley genotype 17.5.16 was not affected by phenylpropanoid biosynthesis but penetration resistance was almost completely inhibited by D-mannose, which reduces the energy available in plant host cells. This suggests a parallel in the cellular basis of penetration resistance between 17.5.16 rust and mlo barleys powdery mildew interaction. Results revealed differing patterns of programmed cell death (PCD) in appropriate versus nonhost rust interactions. PAL and CAD inhibitors reduced PCD (hypersensitivity) in appropriate interactions. Conversely, they had no effect in PCD of wheat to P. hordei; whereas D-mannose dramatically reduced nonhost resistance and allowed colony establishment. The differential effects of inhibitors in the expression of the different resistances and the commonalities with the cereal-powdery mildew interaction is analyzed and discussed. 相似文献
5.
The depletion of tylosin from edible pig tissues was studied following 5 days of intramuscular (i.m.) administration of 10 mg/kg of tylosin to 16 crossbreed pigs. Animals were slaughtered at intervals after treatment and samples of muscle, kidney, liver, skin+fat, and injection site were collected and analysed by high-performance liquid chromatography (HPLC). Seven days after the completion of treatment, the concentration of tylosin in kidney, skin+fat, and at the injection site was higher than the European Union maximal residue limit (MRL) of 100 microg/kg. Tylosin residues in all tissues were below the quantification limit (50 microg/kg) at 10 and 14 days post-treatment. 相似文献
6.
Guillem Segarra Eva Casanova Celia Borrero Manuel Avilés Isabel Trillas 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(4):393-402
The incidence/severity of soil-borne plant diseases is often reduced when composts are used as growth media. However, much
less information is available about the effects of composts on the development of foliar diseases. Here we studied the suppressive
capacity of five composts (from olive marc-cotton gin trash, grape marc, cork, spent mushroom and municipal organic and yard
wastes) as growth media against Botrytis cinerea disease in cucumber plants. We also examined the putative correlations of several biotic and abiotic factors involved in
disease suppression. The suppressive capacity of the growth media was studied by comparing disease incidence/severity in plants
grown in composts with that occurring in plants grown in commercial peats, which are conducive to most soilborne diseases.
Correlations were made between the occurrence of disease and leaf nutrient status, as well as electrical conductivity (EC)
and microbial activity (measured as β-glucosidase activity) in the growth media. Cucumber plants grown in the peats showed
greater severity of B. cinerea during the bioassay than those grown in composts. Mo, Ca and Si content in leaves showed negative correlations with this
disease. A negative correlation with disease severity was observed for EC and microbial activity in the growth media. The
noticeable reduction in B. cinerea in plants grown in composts was related to the supply of specific chemical elements, a certain degree of salt stress, and
the high microbial activity of composts. 相似文献
7.
8.
Summary The content of coumarins, as probable phytoalexins, was analysed in four sunflower genotypes that ranged in responses to head
rot from highly susceptible to highly resistant. Low levels of all coumarins (scopolin, scopoletin and ayapin) were detected
in the three most susceptible genotypes irrespective of time after inoculation. However, in the resistant genotype there was
a clear time-dependent disease-induced increase of all coumarins that reached a maximum after 10–14 days. Detailed comparison
of the most susceptible and the resistant genotype showed that in the resistant but not the susceptible, scopoletin peroxidase
activity increased during the course of the experiment. Results confirmed a clear negative correlation between coumarin content
and disease symptoms and in particular for scopolin. Furthermore we show for the first time that scopolin is inhibitory to
Sclerotinia at similar doses to scopoletin. As scopolin is known to be less phytotoxic than ayapin and scopoletin, its accumulation may
well confer head rot resistance with minimal plant damage and might be one of the bases for resistance to Sclerotinia. 相似文献
9.
Biotechnology approaches to overcome biotic and abiotic stress constraints in legumes 总被引：1，自引：0，他引：1
Miguel A. Dita Nicolas Rispail Elena Prats Diego Rubiales Karam B. Singh 《Euphytica》2006,147(1-2):1-24
Summary Biotic and abiotic stresses cause significant yield losses in legumes and can significantly affect their productivity. Biotechnology
tools such as marker-assisted breeding, tissue culture, in vitro mutagenesis and genetic transformation can contribute to solve or reduce some of these constraints. However, only limited
success has been achieved so far. The emergence of “omic” technologies and the establishment of model legume plants such as
Medicago truncatula and Lotus japonicus are promising strategies for understanding the molecular genetic basis of stress resistance, which is an important bottleneck
for molecular breeding. Understanding the mechanisms that regulate the expression of stress-related genes is a fundamental
issue in plant biology and will be necessary for the genetic improvement of legumes. In this review, we describe the current
status of biotechnology approaches in relation to biotic and abiotic stresses in legumes and how these useful tools could
be used to improve resistance to important constraints affecting legume crops. 相似文献
10.
Color polymorphisms have become a major topic in evolutionary biology and substantial efforts have been devoted to the understanding of the mechanisms responsible for originating such colorful systems. Within-morph continuous variation, on the other hand, has been neglected in most of the studies. Here, we combine spectrophotometric/visual modeling and genetic data to study the mechanisms promoting continuous variation within categorical color morphs of Podarcis muralis. Our results suggest that intra-morph variability in the pterin-based orange morph is greater compared to white and yellow morphs. We also show that continuous variation within the orange morph is partially discriminable by conspecifics. Genotyping results indicate that allelic variants at the BCO2 locus (responsible for deposition of yellow carotenoids) contribute to generate continuous variation in orange individuals. However, other intrinsic and/or extrinsic mechanisms, such as body size, might be involved, opening a new avenue for future research on the drivers of continuous variation within-morphs. 相似文献