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51.
Felipe André Sganzerla Graichen José Antônio Martinelli Caroline de Lima Wesp Luis Carlos Federizzi Márcia Soares Chaves 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(3):497-510
Crown rust, caused by Puccinia coronata f. sp. avenae, can cause significant damage in all regions where oats (Avena sativa L.) are cultivated. The primary means of controlling crown rust has been through genetic resistance, although in most cases
resistance has been quickly overcome by the pathogen. More durable partial or non-specific resistance may possess different
mechanisms from those underlying genes with specific effects. We studied the epidemiological and histological components of
crown rust resistance with potential use in plant protection. Among the components evaluated, pustule density showed the clearest
effect on resistance, while the latent period was not an important component. Cell death associated with the accumulation
of autofluorescent and phenolic compounds was common in the resistant genotypes, but temporally distinct for the genotypes
studied. Genotype Pc68/5*Starter, which has race-specific resistance, showed rapid cell death that prevented the development
of pathogen colonies. Conversely, with cultivar URS 21 and genotypes 04B7113-1 and 04B7119-2, cell death and associated accumulation
of autofluorescent and phenolic compounds was delayed until pathogen colonies were already established. Pathogen colonies
developed normally in susceptible plants genotypes, and had usually produced sporogenic tissue by 5 days after inoculation.
The data suggest that the resistance mechanisms, especially hypersensitivity and phenolic compound production, active in resistant
plants are similar but may be differently expressed over time. The temporal variation in the expression of hypersensitivity
and phenolic compound production reflects the level of field resistance in these genotypes. 相似文献
52.
M. Vaz J. Maroco N. Ribeiro L. C. Gazarini J. S. Pereira M. M. Chaves 《Agroforestry Systems》2011,82(2):173-181
We studied morphological, biochemical and physiological leaf acclimation to incident Photon-Photosynthetic-Flux-Density (PPFD) in Quercus ilex (holm oak) and Quercus suber (cork oak) at Mediterranean evergreen oak woodlands of southern Portugal. Specific leaf area (SLA) decreased exponentially with increasing PPFD in both species. Q. ilex had lower SLA values than Q. suber. Leaf nitrogen, cellulose and lignin concentration (leaf area-based) scaled positively with PPFD. Maximum rate of carboxylation (Vcmax), capacity for maximum photosynthetic electron transport (Jmax), rate of triose-P utilization (VTPU) and the rate of nonphotorespiratory light respiration (Rd) were also positively correlated with PPFD in both Quercus species, when expressed in leaf area but not on leaf mass basis. Q suber showed to have higher photosynthetic potential (Vcmax, Jmaxm and VTPUm) and a higher nitrogen efficient nitrogen use than Q.ilex. Leaf chlorophyll concentration increased with decreasing PPFD, improving apparent quantum use efficiency (Φ) in both Quercus species. We concluded that, in Q.ilex and Q.suber, leaf structural plasticity is a stronger determinant for leaf acclimation to PPFD than biochemical and physiological plasticity. 相似文献
53.
54.
P CHAMNANPOOD PC CLELAND† FC BALDOCK‡ LJ GLEESONt† § 《Australian veterinary journal》1995,72(4):142-144
SUMMARY: A study was undertaken in northern Thailand to examine the involvement of pigs in outbreaks of foot-and-mouth disease (FMD). Data were collected by surveying selected villages, by serological monitoring of pigs and by investigating outbreaks. Fifty-three of 58 villages (91%) surveyed reported that pigs did not develop FMD during the most recent outbreak. The source of 49/60 (82%) outbreaks was attributed to either recent purchases of infected cattle and buffalo or commingling of cattle and buffalo with stock from an infected neighbouring village. One of 60 villages (1.7%) reported that the source was introduced infected pigs. There was no association between the various hypothesised risk factors relating to the management of pigs and the frequency of FMD outbreaks in the survey. The percentage of seropositive pigs during 3 rounds of serological monitoring conducted at 6-monthly intervals in selected villages was 3.5%, 2.6% and 0%, respectively. No clinically affected pigs were observed in 11 outbreak investigations. It was concluded that pigs did not commonly become infected when there were outbreaks of FMD in village cattle and buffalo in northern Thailand. This was probably due to the pig feeding and housing practices employed by villagers that protected pigs from exposure to virus from infected cattle or buffalo, or their products. 相似文献
55.
Martínez Pastur Guillermo José Cellini Juan M. Chaves Jimena E. Rodríguez-Souilla Julián Benitez Julieta Rosas Yamina M. Soler Rosina M. Lencinas María V. Peri Pablo L. 《Agroforestry Systems》2022,96(7):1039-1052
Agroforestry Systems - Sustainable forest management is proposed as a solution for many ecological and socio-economic trade-offs associated with different forest uses. In Patagonia, silvopastoral... 相似文献
56.
Patrícia Aparecida Cardoso da LUZ Paulo Ramos da Silva SANTOS Cristiana ANDRIGHETTO André Mendes JORGE Ant?nio Chaves de ASSIS NETO 《The Journal of reproduction and development》2013,59(1):14-17
Buffalo are an economically important source for meat and milk production, especially in
Brazil. However, important aspects of their biology remain unknown thus far. Herein, we
describe the reproductive characteristics of male Murrah buffalo (Bubalus
bubalis) raised under extensive management conditions by applying biometrics
associated with testicular weight. We analyzed seven males, divided into two groups: G1,
which consisted of four 18-month-old animals, and G2, which consisted of three
24-month-old animals. Testicular development occurs slowly in Murrah buffalo, suggesting a
delay of sexual maturity. The biometric testicular parameters analyzed were scrotal
circumference, testicular weight, testicular length, testicular width, testicular
thickness and testicular circumference. Our data indicate strong correlations between SC,
age and body weight, and additional significant relationships were identified between body
weight, age and other testicular parameters. Thus, these parameters are suitable
indicators when selecting bulls for breeding purposes. 相似文献
57.
Ariel Vicente Bernardo Repice Gustavo Martínez Alicia Chaves Pedro Civello 《The Journal of Horticultural Science and Biotechnology》2013,88(2):246-251
SummaryMature boysenberries (Rubus hybrid) were harvested, heat-treated (45°C for 1 or 3 h or 47°C for 1 h) or exposed to UV-C light (2.3, 4.6 or 9.2 kJ m–2), and stored at 20°C for 2 d. Fruit treated with 9.2 kJ m–2 or 45°C for 1 h showed less damaged drupelets per fruit and/or remained firmer than untreated fruit after 2 d. Those treatments were selected for further analyses. In another experiment, boysenberries were either UV-C (9.2 kJ m–2) or heat-treated (45°C for 1 h) and stored either at 20°C for 1 d or at 0°C for 4 d before transfer to 20°C for 1 d. Both UV-C and heat treatments reduced softening and/or fruit damage. Treated fruit had lower respiration rates and anthocyanin leakage than control fruit suggesting greater tissue integrity. Titratable acidity, pH, total sugar content and antioxidant activity in treated fruit showed fewer changes than in control fruit when stored at 20°C for 1 d. Results suggest that heat or UV-C treatment, alone or in combination with refrigerated storage, may be a useful non-chemical mean of maintaining boysenberry fruit quality and extending postharvest life. 相似文献
58.
Renan O. Silva Ana Paula M. Santana Nathalia S. Carvalho Talita S. Bezerra Camila B. Oliveira Samara R. B. Damasceno Luciano S. Chaves Ana Lúcia P. Freitas Pedro M. G. Soares Marcellus H. L. P. Souza André Luiz R. Barbosa Jand-Venes R. Medeiros 《Marine drugs》2012,10(12):2618-2633
Red seaweeds synthesize a great variety of sulfated galactans. Sulfated polysaccharides (PLSs) from seaweed are comprised of substances with pharmaceutical and biomedical potential. The aim of the present study was to evaluate the protective effect of the PLS fraction extracted from the seaweed Gracilaria birdiae in rats with naproxen-induced gastrointestinal damage. Male Wistar rats were pretreated with 0.5% carboxymethylcellulose (control group—vehicle) or PLS (10, 30, and 90 mg/kg, p.o.) twice daily (at 09:00 and 21:00) for 2 days. After 1 h, naproxen (80 mg/kg, p.o.) was administered. The rats were killed on day two, 4 h after naproxen treatment. The stomachs were promptly excised, opened along the greater curvature, and measured using digital calipers. Furthermore, the guts of the animals were removed, and a 5-cm portion of the small intestine (jejunum and ileum) was used for the evaluation of macroscopic scores. Samples of the stomach and the small intestine were used for histological evaluation, morphometric analysis and in assays for glutathione (GSH) levels, malonyldialdehyde (MDA) concentration, and myeloperoxidase (MPO) activity. PLS treatment reduced the macroscopic and microscopic naproxen-induced gastrointestinal damage in a dose-dependent manner. Our results suggest that the PLS fraction has a protective effect against gastrointestinal damage through mechanisms that involve the inhibition of inflammatory cell infiltration and lipid peroxidation. 相似文献
59.
Aline Medeiros de Paula Mendes Dulciene Karla de Andrade Silva Marcelo de Andrade Ferreira Antonia Sherlânea Chaves Veras Geane Dias Gonçalves Ferreira Ricardo Brauer Vigoderis Helton Gregory Santos Arcanjo Jarbas Miguel Silva Jr. Josimar Santos de Almeida Anna Christine Alencar Fotius Glébio de Almeida Farias 《Tropical animal health and production》2012,45(1):231-237
The aim of this study was to assess the effect of different supplements on the behavior variables of crossbred dairy cows that were in pasture that comprised two 4?×?4 Latin squares (four periods, four treatments, and four animals). Each experimental period lasted 15 days (10 days to adapt animals to treatments and 5 days for data collection). The animals were supplemented twice a day, with different forage (corn silage and cactus pear) and concentrate sources (soy mea + wheat meal + corn meal + cotton seed together and soy meal as a single constituent of the concentrate). A significant difference (p?<?0.10) was observed for the percentage of time spent consuming the supplement and for idleness, rumination, and bite rate at the time of supplementation. The supplement intake period was greater for the cactus pear-based supplements due to the lower dry matter content. Those based on corn silage resulted in longer rumination periods than those consisting of cactus pear; however, the opposite was observed for supplements based on the cactus, which showed higher percentages of time for idleness. The supplementation influenced the ingestive behavior of crossbred dairy cows. 相似文献
60.
Alla Shvaleva Filipe Costa e Silva Paula Scotti Mouhssin Oufir Jean-François Hausman Guignard Cedric Paula Ramos M. Helena Almeida M. Lucília Rodrigues João S. Pereira M. Manuela Chaves 《Annals of Forest Science》2008,65(2):204-204
We have compared the metabolic responses of leaves and roots of two Eucalyptus globulus L. clones CN5 and ST51 that differ in their sensitivity to water deficits (ST51 is more drought sensitive), with regard to the effect of chilling (10/5 °C, day/night). We studied changes in growth, osmotic potential and osmotically active compounds, soluble proteins, leaf pigments, and membrane lipid composition. Our data showed that both clones have the ability to acclimatize to chilling temperatures. As a result of 10 days of acclimation, an increase of soluble sugars in leaves of treated plants of both clones was observed that disappeared later on. Differences between clones were observed in the photosynthetic pigments and soluble protein content which were more stable in CN5 under chilling. It also was apparent that CN5 presented a less negative predawn water potential (ψpd) and a higher leaf turgor than ST51 throughout the chilling treatment. In the case of the CN5, increased total lipids (TEA) and concomitant increase of linolenic acid (C18:3) in leaves after acclimatization may be related to a better clone performance under chilling temperatures. Moreover, a higher constitutive investment in roots in the case of CN5 as compared to ST51 may benefit new root regeneration under low temperatures favoring growth after cold Mediterranean winter. 相似文献