排序方式: 共有73条查询结果,搜索用时 15 毫秒
31.
Xoaquín Moreira Luis Sampedro Rafael Zas Alejandro Solla 《Trees - Structure and Function》2008,22(6):771-777
Changes in resource availability and biotic and abiotic stress may alter the defensive mechanisms of pine trees. The effect
of fertilisation on the resin canal structure of Pinus pinaster seedlings established in two trials in NW Spain, one attacked by Hylobius abietis and the other non-attacked, was studied. The leaders of 50 plants were destructively sampled and the resin canal density,
the canal area and its relative conductive area in the phloem and xylem were assessed. Experimentally increased nutrient availability
significantly decreased resin canal density in the phloem of the seedlings in the two analysed trials, where unfertilised
seedlings presented up to 30% more resin canal density than the fertilised seedlings (mean value ± SEM = 0.32 ± 0.02 resin
canals mm−2 in the fertilised plants versus 0.45 ± 0.04 resin canals mm−2 in the control plants). Fertilisation had no effect on the resin canal system in the xylem, but significantly increased tracheid
size. Significant differences of resin canals among sites were observed mainly in the xylem; the resin canal density was 1.7-fold
greater in the attacked site than in the non-attacked site. The similar structure of phloem resin canals in both sites supports
that phloem resin canals are constitutive mechanisms of defence in P. pinaster, whereas xylem resin canals would be constitutive mechanisms but also inducible mechanisms of resistance following the attack
of pine weevils or bark beetles.
XM and LS equally contributed to this paper. 相似文献
32.
Rüdiger Felix Solla 《Plant Systematics and Evolution》1878,28(10):331-334
Ohne Zusammenfassung 相似文献
33.
Dr. R. F. Solla 《Plant Systematics and Evolution》1891,41(10):340-345
Ohne Zusammenfassung 相似文献
34.
Dr. R. F. Solla 《Plant Systematics and Evolution》1889,39(1):60-69
Ohne Zusammenfassung 相似文献
35.
Dr. Solla 《Plant Systematics and Evolution》1884,34(10):381-379
Ohne Zusammenfassung 相似文献
36.
37.
Rüdiger Felix Solla 《Plant Systematics and Evolution》1879,29(11):341-353
Ohne ZusammenfassungZum Schlüsse kann ich nicht umhin, Herrn Prof. J. Wiesner, über dessen Anregung und mit dessen freundlicher Hilfe vorliegende kleine Arbeit zu Stande gebracht wurde, sowie Herrn Universitäts-Assistenten Dr. K. Mikosch, für oft bewiesene Zuvorkommenheit meinen wärmsten Dank auszusprechen. 相似文献
38.
Shane R. de Solla Kim J. Fernie Glenn C. Barrett Christine A. Bishop 《Biodiversity and Conservation》2006,15(11):3481-3497
Many acoustic surveys have been initiated to monitor anuran populations in North America. We used the Ontario Backyard Frog
Survey to examine temporal and spatial trends, from 1994 to 2001. Our data suggest that there have been no consistent trends
in site occupancy during this time period, but there were some differences among years. Both American toads and northern leopard
frogs were more prevalent in 1995 than in 1994. Similarly, species richness was higher in 1995 and 1996 compared to most other
years. Individual populations of species, however, often were not stable. Extinction and colonization rates varied among species,
and ranged from 1.5 to 19.5% per year, and site occupancy was negatively correlated with extinction rates. Daily detection
probabilities were often quite low, and were primarily driven by the perceived calling intensity. We recommend: (i) that monitoring
programs attempt to preserve common survey routes, despite heavy turnover of volunteers, (ii) calling surveys be timed to
maximize detection probabilities, and (iii) analyses based upon landscape features and GIS approaches should be used to determine
localized changes in site occupancy or species richness. 相似文献
39.
Yuri Costa Sarno Neves Victor Augusto Camarinha de Castro-Lima Davi Jorge Fontoura Solla Vivian Simone de Medeiros Ogata Fernando Linhares Pereira Jordana Machado Araujo Ana Catharina Seixas Nastri Yeh-Li Ho Maria Cristina Chammas 《PLoS neglected tropical diseases》2021,15(7)
BackgroundYellow fever (YF) is a hemorrhagic disease caused by an arbovirus endemic in South America, with recent outbreaks in the last years. Severe cases exhibit fulminant hepatitis, but there are no studies regarding its late-term effects on liver parenchyma. Thus, the aim of this study was to determine the frequency and grade of liver fibrosis in patients who recovered from severe YF and to point out potential predictors of this outcome.Methodology/Principal findingsWe followed-up 18 patients who survived severe YF during a recent outbreak (January-April 2018) in Brazil using ultrasound (US) with shear-wave elastography (SWE) at 6 months after symptoms onset. No patient had previous history of liver disease.Median liver stiffness (LS) was 5.3 (4.6–6.4) kPa. 2 (11.1%) patients were classified as Metavir F2, 1 (8.3%) as F3 and 1 (8.3%) as F4; these two last patients had features of cardiogenic liver congestion on Doppler analysis. Age and cardiac failure were associated with increased LS (p = 0.036 and p = 0.024, respectively). SAPS-3 at ICU admission showed a tendency of association with significant fibrosis (≥ F2; p = 0.053). 7 patients used sofosbuvir in a research protocol, of which none showed liver fibrosis (p = 0.119).Conclusions/SignificanceWe found a low frequency of liver fibrosis in severe YF survivors. US with SWE may have a role in the follow up of patients of age and / or with comorbidities after hospital discharge in severe YF, a rare but reemergent disease. 相似文献
40.
María Vivas Cláudia Nunes Manuel A. Coimbra Alejandro Solla 《Trees - Structure and Function》2014,28(2):373-379