Spring drought is becoming a frequently occurring stress factor in temperate forests. However, the understanding of tree resistance and resilience to the spring drought remains insufficient. In this study, European beech (Fagus sylvatica L.) seedlings at the early stage of leaf development were moderately and severely drought stressed for 1 month and then subjected to a 2-week recovery period after rewatering. The study aimed to disentangle the complex relationships between leaf gas exchange, vascular anatomy, tree morphology and patterns of biomass allocation. Stomatal conductance decreased by 80 and 85% upon moderate and severe drought stress, respectively, which brought about a decline in net photosynthesis. However, drought did not affect the indices of slow chlorophyll fluorescence, indicating no permanent damage to the light part of the photosynthetic apparatus. Stem hydraulic conductivity decreased by more than 92% at both drought levels. Consequently, the cambial activity of stressed seedlings declined, which led to lower stem biomass, reduced tree ring width and a lower number of vessels in the current tree ring, these latter also with smaller dimensions. In contrast, the petiole structure was not affected, but at the cost of reduced leaf biomass. Root biomass was reduced only by severe drought. After rewatering, the recovery of gas exchange and regrowth of the current tree ring were observed, all delayed by several days and by lower magnitudes in severely stressed seedlings. The reduced stem hydraulic conductivity inhibited the recovery of gas exchange, but xylem function started to recover by regrowth and refilling of embolized vessels. Despite the damage to conductive xylem, no mortality occurred. These results suggest the low resistance but high resilience of European beech to spring drought. Nevertheless, beech resilience could be weakened if the period between drought events is short, as the recovery of severely stressed seedlings took longer than 14 days.
- MeSH
- Fagus * MeSH
- Photosynthesis MeSH
- Plant Leaves MeSH
- Droughts * MeSH
- Seedlings MeSH
- Water MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The vaginal rings research is almost exclusively focused on rings for human medicine, although the dosage form offers improvement of therapeutic effect in other mammals as well. This contribution studied an effect of varying dimension parameters (diameter 20, 30 or 40 mm; height 3, 4 or 5 mm; width of annulus 5, 7.5 or 10 mm) on mechanical properties and dissolution behaviour of silicone vaginal rings with constant drug amount, intended for use in dogs. Results showed that altering dimensions influenced mechanical properties (compressive force, tensile strength and resistance of removal thread), in vitro drug release and water uptake. The removal thread resistance was increasing with increasing height and width. Compression force was higher for the rings with smaller diameter. The total drug release was increasing with decreasing height and rising diameter, surface area and water uptake during dissolution test. The initial dissolution rate was slower for the rings with higher width. As the best candidate for use in model dog subjects, the ring with 30 mm diameter, 3 mm height and 7.5 mm width was found. These drug-free vaginal rings were further tested in in vivo safety study. The results did not show any major deviation from the physiological conditions. Graphical abstract.
- MeSH
- Contraceptive Devices, Female * MeSH
- Mechanical Phenomena MeSH
- Tensile Strength MeSH
- Dogs MeSH
- Solubility MeSH
- Toxicity Tests MeSH
- Drug Liberation MeSH
- Animals MeSH
- Check Tag
- Dogs MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
During the growing season, trees allocate photoassimilates to increase their aboveground woody biomass in the stem (ABIstem). This 'carbon allocation' to structural growth is a dynamic process influenced by internal and external (e.g., climatic) drivers. While radial variability in wood formation and its resulting structure have been intensively studied, their variability along tree stems and subsequent impacts on ABIstem remain poorly understood. We collected wood cores from mature trees within a fixed plot in a well-studied temperate Fagus sylvatica L. forest. For a subset of trees, we performed regular interval sampling along the stem to elucidate axial variability in ring width (RW) and wood density (ρ), and the resulting effects on tree- and plot-level ABIstem. Moreover, we measured wood anatomical traits to understand the anatomical basis of ρ and the coupling between changes in RW and ρ during drought. We found no significant axial variability in ρ because an increase in the vessel-to-fiber ratio with smaller RW compensated for vessel tapering towards the apex. By contrast, temporal variability in RW varied significantly along the stem axis, depending on the growing conditions. Drought caused a more severe growth decrease, and wetter summers caused a disproportionate growth increase at the stem base compared with the top. Discarding this axial variability resulted in a significant overestimation of tree-level ABIstem in wetter and cooler summers, but this bias was reduced to ~2% when scaling ABIstem to the plot level. These results suggest that F. sylvatica prioritizes structural carbon sinks close to the canopy when conditions are unfavorable. The different axial variability in RW and ρ thereby indicates some independence of the processes that drive volume growth and wood structure along the stem. This refines our knowledge of carbon allocation dynamics in temperate diffuse-porous species and contributes to reducing uncertainties in determining forest carbon fixation.
Climatic constraints on tree growth mediate an important link between terrestrial and atmospheric carbon pools. Tree rings provide valuable information on climate-driven growth patterns, but existing data tend to be biased toward older trees on climatically extreme sites. Understanding climate change responses of biogeographic regions requires data that integrate spatial variability in growing conditions and forest structure. We analyzed both temporal (c. 1901-2010) and spatial variation in radial growth patterns in 9,876 trees from fragments of primary Picea abies forests spanning the latitudinal and altitudinal extent of the Carpathian arc. Growth was positively correlated with summer temperatures and spring moisture availability throughout the entire region. However, important seasonal variation in climate responses occurred along geospatial gradients. At northern sites, winter precipitation and October temperatures of the year preceding ring formation were positively correlated with ring width. In contrast, trees at the southern extent of the Carpathians responded negatively to warm and dry conditions in autumn of the year preceding ring formation. An assessment of regional synchronization in radial growth variability showed temporal fluctuations throughout the 20th century linked to the onset of moisture limitation in southern landscapes. Since the beginning of the study period, differences between high and low elevations in the temperature sensitivity of tree growth generally declined, while moisture sensitivity increased at lower elevations. Growth trend analyses demonstrated changes in absolute tree growth rates linked to climatic change, with basal area increments in northern landscapes and lower altitudes responding positively to recent warming. Tree growth has predominantly increased with rising temperatures in the Carpathians, accompanied by early indicators that portions of the mountain range are transitioning from temperature to moisture limitation. Continued warming will alleviate large-scale temperature constraints on tree growth, giving increasing weight to local drivers that are more challenging to predict.
- MeSH
- Pinus * MeSH
- Climate Change MeSH
- Forests MeSH
- Picea * MeSH
- Temperature MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
A new species of the recently erected genus of proteocephalid cestodes, Synbranchiella Arredondo, Alves and Gil de Pertierra, 2017 , is described based on specimens found in the mountain mullet, Dajaus monticola (Bancroft, 1834), from Costa Rica. The new species is placed in Synbranchiella because of the cortical position of the genital organs (typical of the former subfamily Monticelliinae); a robust scolex (lacking a metascolex) having a dome-shaped apex and biloculate suckers (lacking free posterior margins); vitelline follicles in 2 narrow lateral bands; a vagina always anterior to the cirrus-sac; and a genital pore that is markedly pre-equatorial, i.e., close to the anterior margin of proglottids. The new species, Synbranchiella megacirrus, differs from the type and only other species of the genus, Synbranchiella mabelae Arredondo, Alves and Gil de Pertierra, 2017 , that infects the marbled swamp eel, Synbranchus marmoratus Bloch, 1795, in Argentina by the absence of preporal vitelline follicles (present in S. mabelae); a well-developed, large, elongate vaginal sphincter (small and ring-like in S. mabelae); and a large cirrus-sac relative to the proglottid size (cirrus-sac length is on average 48% of the proglottid width in S. megacirrus vs. 31% in the latter species). This is the first adult tapeworm reported from mountain mullet and the first record of the genus outside of South America, thereby greatly extending the range of distribution of species of Synbranchiella.
- MeSH
- Cestoda anatomy & histology classification MeSH
- Cestode Infections parasitology veterinary MeSH
- Fish Diseases parasitology MeSH
- Fresh Water MeSH
- Smegmamorpha parasitology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Costa Rica MeSH
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2970 dead and 4224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca. 84% of the mortality events. The extent and duration of these reductions were highly variable (1-100 years in 96% of events) due to the complex interactions among study species and the source(s) of mortality. Strong and long-lasting declines were found for gymnosperms, shade- and drought-tolerant species, and trees that died from competition. Angiosperms and trees that died due to biotic attacks (especially bark-beetles) typically showed relatively small and short-term growth reductions. Our analysis did not highlight any universal trade-off between early growth and tree longevity within a species, although this result may also reflect high variability in sampling design among sites. The intersite and interspecific variability in growth patterns before mortality provides valuable information on the nature of the mortality process, which is consistent with our understanding of the physiological mechanisms leading to mortality. Abrupt changes in growth immediately before death can be associated with generalized hydraulic failure and/or bark-beetle attack, while long-term decrease in growth may be associated with a gradual decline in hydraulic performance coupled with depletion in carbon reserves. Our results imply that growth-based mortality algorithms may be a powerful tool for predicting gymnosperm mortality induced by chronic stress, but not necessarily so for angiosperms and in case of intense drought or bark-beetle outbreaks.
Based on light and scanning electron microscopical studies, three new species of philometrids (Nematoda: Philometridae) are described from females collected in marine perciform fishes off the northern coast of Australia: Philometra gracilis n. sp. and Philometroides branchiarum n. sp. from tissues behind the gills and gill arches, respectively, of the John's snapper Lutjanus johnii (Bloch) (Lutjanidae), and Philometroides stomachicus n. sp. from the stomach wall of the blackspotted croaker Protonibea diacanthus (Lacépède) (Sciaenidae). Philometra gracilis differs from other congeners described from the Lutjanidae mainly in the presence of large caudal projections, short gravid females (28-42 mm long), the oesophageal gland extending anteriorly far anterior to the level of the nerve-ring, the site in the host and its geographical distribution. Philometroides branchiarum is mainly characterised by the possession of conspicuous, sclerotised oesophageal teeth and very short gravid females (6-8 mm long), whereas P. stomachicus can be differentiated by the body length of gravid females (85-90 mm), the length of the oesophagus (2.67 mm) representing 3% of the body length, the maximum width/body length ratio of gravid females (1:28-32), cuticular bosses densely distributed throughout the body but absent from the oesophageal region, the absence of oesophageal teeth and caudal projections, and the site in the host. The presence of P. gracilis and P. branchiarum in L. johnii and that of P. stomachicus in P. diacanthus confirm the possibility of the coexistence of more philometrid species in different sites within sympatric specimens of one and the same definitive host.
- MeSH
- Dracunculoidea anatomy & histology classification MeSH
- Species Specificity MeSH
- Microscopy, Electron, Scanning MeSH
- Perciformes parasitology MeSH
- Gills parasitology MeSH
- Animals MeSH
- Check Tag
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Australia MeSH
- Pacific Ocean MeSH
... off, grow up, break down have a try, I’ve got a bicycle make a mistake, do homework give someone a ring ... ... clock, during my lecture 96 -- 26 per cent, two and a half, divide 97 a long way, too far, length, width ...
new edition 142 s. : il.
... and Closed Shapes (Paths) 62 -- 4.1.2.04 Outline Attributes Overview 63 -- 4.1.2.05 Outline (Line) Width ... ... Overview 196 -- 5.2.5.2 Single Pie Chart 197 -- 5.2.5.3 Pie Charts with Detached Slices 198 -- 5.2.5.4 Ring ... ... Pie Charts 199 -- 5.2.5.5 Multiple-Pie Chart 200 -- 5.2.5.6 Multiple-Ring Pie Chart 201 -- 5.2.5.7 Paired ... ... 5.3.4 3-D AREA CHARTS 214 -- 5.3.5 3-D PIE CHARTS 215 -- 5.3.5.1 3-D Pie Charts 215 -- 5.3.5.2 3-D Ring ...
1st ed. 352 s. : il. ; 24 cm
... (Hannover): Verhalten von Thrombozytenzahl, Mean Platelet Volume und Platelet Distribution Width bei ... ... 329 -- Steinhoff, G.; Wonigeit, K.; Lauchart, W.; Ringe, B.; Kuse, E.; Pichlmayr, R. ...
Beiträge zur Infusionstherapie und klinische Ernährung ; Band 18
412 s. : il.
