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81.
Samah Mhamdi Oliver Brendel Pierre Montpied Hanah Ghouil-Amimi Ibrahim Hasnaoui Erwin Dreyer 《Annals of Forest Science》2013,70(7):675-684
?Context
Oak species display a large within-species diversity combined with significant gene flow between species. Quercus afares Pomel is an endemic species that grows as a small relict population in Northern Tunisia, together with Quercus suber L. and Quercus canariensis Willd. It is considered to be a fixed hybrid between the two latter.?Aims
We tested (1) whether this population of Q. afares is declining with respect to the neighbouring populations of the two other species and (2) whether the spatial distribution of leaf morphology is random among individuals within this small population of Q. afares or influenced by the neighbouring species.?Methods
Spatial distribution and diameter at breast height were recorded in the population of Q. afares. We identified two perpendicular transects across the population reaching from areas dominated by Q. canariensis to areas dominated by Q. suber and defined 20 plots along each. Eleven traits were assessed on 10 leaves collected from the upper crown of trees from the three species. A multiple correspondence analysis and an ANOVA were used to test for within and between-species diversity in leaf morphology.?Results
Q. afares individuals occurred at a low frequency among the two other species. Nevertheless, Q. afares showed no particular evidence of decline with respect to the two other species. Leaf traits displayed a large inter-specific variability with very little overlap between Q. afares and Q. suber and some between Q. afares and Q. canariensis. A high level of diversity was detected for these traits within Q. afares, but we were unable to unravel any spatial organisation of this diversity; in Q. afares, leaf traits varied independently of the presence of neighbouring Q. suber or Q. canariensis.?Conclusion
Q. afares seems to be a fixed species with specific leaf traits that are independent of that of the species of the neighbouring trees. This population is not suffering a detectable trend towards decline except for the lack of any visible regeneration below any of the three species. 相似文献82.
83.
84.
Typical symptoms of rubberwood canker found in East Kalimantan, Indonesia, differ from those of conventional rubberwood peach
canker. Rubberwood canker showed a conspicuous longitudinal canker with exposed xylem that was discolored and decayed. Bark
wounds, resulting from regular tapping, were enclosed within the xylem, and the tissues had become integrated. The characteristics
of abnormal and decayed xylem in this rubberwood canker were analyzed by light microscopy and scanning electron microscopy.
Xylem in the vicinity of the enclosed bark contained fewer vessels of smaller diameter and shorter length, and significantly
wider rays compared with normal xylem. Around the wide growth zones of the canker, axial cells were disoriented and warped
toward the canker zones. In view of the separation among cells, and the concentric degradation of the cell walls starting
from the lumen surfaces, decayed xylem appeared to be caused mainly by white-rot fungal attack. 相似文献
85.
Julia Seeber G. U. H. Seeber Reinhard Langel Stefan Scheu Erwin Meyer 《Biology and Fertility of Soils》2008,44(5):783-790
The effect of 15N-labelled litter of different quality (Luzula sylvatica, a grass species, Vaccinium gaultheroides, a deciduous dwarf shrub, and Calluna vulgaris, a hardy dwarf shrub) and the presence of macro-decomposers (Lumbricus rubellus, Lumbricidae, and Enantiulus nanus, Diplopoda) on the growth of Dactylis glomerata (Poaceae), a grass species abundant on alpine pastureland, was investigated. After 4 months, the presence of soil animals
significantly increased litter mass loss of L. sylvatica, V. gaultheroides and C. vulgaris by 27%, 11% and 40%, respectively. Soil animals generally reduced microbial biomass but significantly increased it in treatments
where either L. sylvatica or C. vulgaris was present. The presence of soil animals significantly increased shoot and root biomass of D. glomerata by 48% and 64%, respectively. L. rubellus increased the transfer of 15N from the litter into plants. We conclude that macro-decomposers increased nutrient mobilization and plant uptake of nutrients
mineralized from recalcitrant litter materials. Litter of L. sylvatica contributed most to the 15N uptake by D. glomerata, suggesting that litter quality is crucial for the cycling of nutrients on abandoned alpine pastureland. 相似文献
86.
Ackermann Y Curtui V Dietrich R Gross M Latif H Märtlbauer E Usleber E 《Journal of agricultural and food chemistry》2011,59(12):6360-6368
This study investigated the production of polyclonal (pAB) antibodies and the first time production of monoclonal (mAB) antibodies against the mycotoxin alternariol, and their implementation in enzyme immunoassay (EIA) for the rapid determination of alternariol in foods. Both EIAs were highly sensitive, with detection limits (IC??) of 35 ± 6.9 pg/mL (mAb EIA) and 59 ± 16 pg/mL (pAb EIA). Food products (n = 109; apple and tomato products, white wine) from German retail shops were analyzed. At a detection limit of 1-2 μg/kg, alternariol at 1-13 μg/kg was found with high frequency in apple (67%) and tomato (93%) products. Tomatoes with visible signs of Alternaria infection, stored at room temperature for up to 4 weeks, contained alternariol at levels up to 50 mg/kg, as determined by EIA and HPLC-FLD. It is concluded that the alternariol immunoassays present a versatile screening tool which could facilitate food control for Alternaria toxins. 相似文献
87.
Mostafa Hajji Erwin Dreyer Benoit Marçais 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(1):63-72
Oak powdery mildew, (Erysiphe alphitoides) causes one of the most common diseases of oaks. We assessed the impact of this pathogen on photosynthesis and water relations
of infected leaves using greenhouse-grown oak seedlings. Transpiration of seedlings infected by oak powdery mildew was also
investigated. Altogether, E. alphitoides had a low impact on host gas exchange whether at the leaf or whole plant scale. Maximal stomatal conductance of infected
leaves was reduced by 20–30% compared to healthy controls. Severely infected seedlings did not experience any detectable change
of whole plant transpiration. The reduction in net CO2 assimilation, An, was less than proportional to the fraction of leaf area infected. Powdery mildew reduced both the maximal light-driven electron
flux (Jmax) and the apparent maximal carboxylation velocity (Vcmax) although Vcmax was slightly more impacted than Jmax. No compensation for the infection occurred in healthy leaves of partly infected seedlings as the reduced photosynthesis
in the infected leaves was not paralleled by increased An levels in the healthy leaves of the seedlings. However, E. alphitoides had a strong impact on the leaf life-span of infected leaves. It is concluded that the moderate effect of E. alphitoides on oak might be related to the small impact on net CO2 assimilation rates and on tree transpiration; nevertheless, the severe reduction in leaf life-span of heavily infected leaves
may lead to decreased carbon uptake over the growth season. 相似文献
88.
Erwin Schimitschek 《Journal of pest science》1936,12(11):134-136
Ohne Zusammenfassung 相似文献
89.
Dr. Erwin Lindner 《Journal of pest science》1940,16(2):20-21
Ohne Zusammenfassung 相似文献
90.
Hall JA Van Saun RJ Tornquist SJ Gradin JL Pearson EG Wander RC 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2004,18(6):880-886
The objective of this study was to compare effects of dietary polyunsaturated fatty acid supplementation (corn oil or fish oil) on selected immune responses in normal horses. Two groups of horses (n = 5) were randomly assigned a dietary supplement with either 3.0% corn oil or fish oil for a period of 14 weeks. Plasma fatty acid profiles were monitored to ensure uptake of dietary fatty acids. Cell-mediated immunity was assessed by a delayed-type hypersensitivity (DTH) skin test to keyhole limpet hemocyanin (KLH), and humoral immunity was assessed by measuring antibody titers to KLH. Production of prostaglandin E2 (PGE2), expression of tumor necrosis factor-alpha (TNF-alpha), and phagocytosis of latex beads by bronchoalveolar lavage fluid (BALF) cells were also assessed. Lipopolysaccharide (LPS)-stimulated BALF cells from horses fed corn oil showed a higher production of PGE2 compared with those from horses fed fish oil at 6 and 12 weeks. Production of TNF-alpha by LPS-stimulated BALF cells was higher in both groups of horses at 6, 8, and 12 weeks compared with pretrial values, and phagocytic activity of BALF cells was higher at 8 and 12 weeks, however, there were no differences between the 2 groups of horses. The DTH skin test and antibody titers to KLH revealed no differences between horses fed corn or fish oil. Based on these studies, dietary polyunsaturated fatty acids modulate the inflammatory response of horses. Both fatty acid supplements increased production of the proinflammatory cytokine TNF-alpha, whereas only corn oil increased production of the proinflammatory eicosanoid PGE2 by LPS-stimulated BALF cells. It is possible that fish oil, because it did not increase production of PGE2, could have value in the treatment of equine recurrent airway obstruction or other equine inflammatory diseases. 相似文献