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The anatomical and histological structure of the stomach was examined in François' leaf monkeys (Presbytis francoisi). The stomachs consisted of three parts, the saccus, the tubus gastricus and pars pylorica, and had well-developed taeniae and many haustra. The cardiac gland region occupied the saccular forestomach and the anterior half of the tubus gastricus, while the fundic gland region occupied the posterior half of the tubus gastricus. The pyloric gland region occupied the entire pars pylorica. In the mucosa of the cardiac gland region, villus-like processes were observed. The mucosae of the cardiac and pyloric gland regions contained not only neutral mucins but also acid mucins.  相似文献   

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This paper describes the leaf anatomy of Sabal mauritiiformis (Karst.) Griseb. & H. Wendl., Sabal mexicana Mart. and Sabal yapa Wright ex Becc., three of the four most representative species of the Yucatán Península, in Mexico. These species are locally used: in the roofing of traditional homes, as food (fruits and apical buds), and in the production of hats, brooms and handicrafts. Leaf samples were collected in secondary growth of lower montane rainforest in the state of Quintana Roo and in two home gardens in the state of Yucatán. Herbarium samples were obtained, and samples of blade and petiole were fixed in formaline-acetic acid-alcohol. Cross incisions were made on the blade and petiole, and were dyed with safranin and toluidine blue O. The results show that S. mauritiiformis and S. yapa are morphologically alike: both are tall, slim palm trees; the leaf in S. mauritiiformis is a shorter palm-like structure compared with the other two species. The shape of the main nerve, as seen in cross section, is rectangular in the three species. The hastula in the three species is acuminate and adaxial. The foliar anatomic structure is similar in the three species, although there are some differences. The adaxial an abaxial epidermis of the blade consist of one layer and, superficially, the anticlinal walls are straight; the stomata are intercostal, of the tetracytic type, present on both surfaces in S. mexicana and S. yapa and only on the abaxial surface on S. mauritiiformis. The hypodermis is one layer thick in S. yapa and in S. mexicana and two layers thick in S. mauritiiformis. In the three species the palisade parenchyma consists of several undefined strata as the cells are similar-in shape and size--to the cells in the spongy parenchyma, so there is no marked difference between these strata and the spongy parenchyma seems almost continuous. Both fibrous and vascular bundles are distributed between the hypodermis and the palisade parenchyma; the fiber bundles can be found towards the abaxial surface while the vascular and fiber bundles are located towards the adaxial surface. The fibers, in the three species, are elongated, with the pointed tips, undivided and unseptated. One to three wide vessels of metaxilem can be seen in the vascular bundles, those in S. yapa being the widest in diameter. The vascular bundles are surrounded by thick fiber sheaths which come in pairs. The anatomic structure of the petiole is similar to that of the blade, and is characterized by the many vascular and fiber bundles dispersed in the parenchymatous tissue, and which are very resistant. The histological structure of the blade and petiole reflects strength and flexibility, qualities which make these plants adequate in the construction of roofs for rural housing and other buildings.  相似文献   

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Soils contaminated with hydrocarbons and others contaminants (heavy metals, PCBs, PAHs) were recently discovered in the banks of the Saint-François and Massawippi rivers. The aim of this study is to attempt to date the contamination events using dendrochronological and dendrochemical methods. For this study, dendrochronology is used to indicate the age of trees, identify the morphological growth anomalies, and provide the geochemical profile timeframe, with dendrochemistry used specifically to identify metal element concentrations in the growth rings of the selected specimens. Sampling for the two types of analysis was done on the banks of the Saint-François River in Windsor and Richmond, where the level of hydrocarbon contamination in the soil profiles is among the highest. Core samples were taken from three red ash (Fraxinus pennsylvanica Marsh.) and dendrochemical analyses were done on the tree rings (191 samples). Dendrochemistry was successfully used to determine that there were heavy metals in the rings, and also to estimate the date of the contamination events by using tree-ring wood. Several contamination events were identified through the presence of lead and other metal trace elements (As, Cd, Cu, Ni, and Zn) in the xylem of the trees analyzed at the selected sites. This suggests that various contaminants were transported by the river on several occasions and deposited on floodplains during successive floods. The atmospheric fallout must also be considered as the other source of pollutants recorded in the trees.  相似文献   

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Summary The Seroe Domi Formation is a 350 m-thick sequence of Neogene marine limestones and silicilastic sandstones cropping out on the leeward coast of Cura?ao, Netherlands Antilles. Integrated analyses of lithofacies, biostratigraphy, geochemistry and Sr isotope model age analyses indicate that Seroe Domi Formation has experienced three major episodes of limestone diagenesis and dolomitization (Dolomites I, I′, and II) that have taken place after successive Mio-Plio-Pleistocene depositional and subaerial exposure events (Subunits 1, 2, and 3). Subunit 1, the lowermost 30 to 100 m of the Seroe Domi Formation, is composed of interbedded coralgal grainstone gravity flows, pelagic wackestones, and allochthonous blocks deposited in Middle Miocene deep-water (>500 m) fore-reef and carbonate slope environments. Subunit 2, the uppermost 250 m of the Seroe Domi Formation, consists of coralgal packstones with basement-derived siliciclastic sands that were deposted in shallowing fore-reef to reef-front environments during the Late Miocene to Pliocene. Subunit 3 siliciclastic sandstones were deposited during the Early Pleistocene within erosional cavities in the Subunit 2 limestones, and are overlain by Late Pleistocene Quaternary Limestone Terraces. The petrography, distribution and geochemistry of Dolomites I, I′ and II indicate that they were precipitated from seawater-freshwater mixing zone fluid environments. Dolomite rhombs and meteoric calcite cements within biomolds illustrate that the host Seroe Domi Formation limestones were subaerially exposed prior to each dolomitization event. Dolomite I (δ18O = +1.04 to +2.46% PDB; δ13C = −2.55 to −6.79 PDB;87Sr/86Sr=0.708866 to 0.708915; Zn=0 ppm; Cu=0 ppm) was precipitated from mixtures of seawater with isotopically-depleted freshwater during the late Middle Miocene. Dolomite I′ (δ18O = +2.08 to +3.55 PDB, δ13C = −1.53 to 1.69 PDB,87Sr/86Sr=0.708981−0.709030; Zn=0 ppm; Cu=0 ppm) was also precipitated from mixtures of seawater with isotopically-depleted freshwater, but during late Late Miocene. In contrast, Dolomite II (δ18O = +2.69 to +3.51 PDB; δ13C = −0.34 to +1.53 PDB;87Sr/86Sr=0.708954 to 0.709088; Zn=20 ppm; Cu=20 ppm) precipitated from late Early Pliocene mixtures of seawater with isotopically-depleted freshwater that had derived Zn, Cu, and less-radiogenic Sr from basalts comprising the Cura?ao basement.  相似文献   

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The diet of juvenile and adult twaite shad was studied at a number of freshwater and estuarine sites in the rivers Severn and Wye and in the coastal waters of Cardigan Bay (West Wales). In the Severn estuary and in the freshwater reaches of the Severn and Wye, adult twaite shad consumed little during their pre-spawning migration. In the Severn Estuary post-spawning adults were present during the summer months where they fed actively on mysids, gammarids and shrimps. Mysids dominated the diet of the adults caught in coastal waters during the autumn. The diet of one year old twaite shad was studied in the Severn Estuary. In May the one year olds from the lower estuary consumed mainly gammarids. During the summer months, this age-class moved into the inner estuary where they fed predominantly on mysids.The larvae and juveniles (age 0+) fed mainly on chironomid larvae and pupae and Simuliidae larvae, while in fresh water. In the estuary copepods, cladocerans and mysids dominated the diet of the juveniles. There was some suggestion of an increase in prey size during their period of residency in the estuary. The contrasting distribution of the juveniles in two river systems is discussed in relation to the effects of channelization.  相似文献   

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This is the first record of the presence of the medically important genus Lutzomyia Fran?a in the Department of Guainía, Colombia. Sand flies were collected biting humans in the surroundings of the urban area of the Municipality of Inírida. Three Lutzomyia species were taxonomically identified as L. davisi (Root), L. olmeca bicolor Fairchild & Theodor, and L. antunesi (Coutinho). Additionally, Brumptomyia mesai Sherlock is cited for the first time in the Caribbean Coast of Colombia based on specimens collected with a modified CDC light trap in the Reserva Forestal Protectora Serranía de Coraza y Montes de María, Department of Sucre.  相似文献   

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《Journal of bryology》2013,35(4):288-295
Abstract

This contribution is a result of collaborative work based on the fieldwork organized during a workshop of the Tropical Bryology Group on Mascarene bryophytes in September 2008, and also from previous unpublished records of the authors. We add 35 new taxon records (17 mosses and 18 liverworts) as well as five other interesting records for Réunion Island (Mascarene Archipelago). Grimmia austrofunalis Müll. Hal., Sphagnum magellanicum Brid. subsp. magellanicum, Didymodon tectorum (Müll. Hal.) K. Saito, Anastrophyllum revolutum Steph. and Lejeunea exilis (Reinw. et al.) Grolle are reported for the first time for Africa. Syrrhopodon vardei L. T. Ellis, Ceratolejeunea papuliflora Steph. and Xylolejeunea grolleana (Pócs) X.-L. He & Grolle, previously known as endemic from Madagascar, are here recorded for Réunion. The latter species is also illustrated with SEM pictures.  相似文献   

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The implications for fish populations of long- (multi-decadal, 1919–2007), medium- (inter-annual) and short- (seasonal, daily) term variations in water temperatures and levels were examined in the St. Lawrence River (SLR). The effects of the seasonal thermal regime of the SLR and its tributaries on the thermal budgets of resident and migrating fish were contrasted. Over the 1919–2007 period, the mean annual water level in Montreal declined significantly; for a discharge of 8,000 m3 s−1, levels dropped steadily by about 3.6 cm year−1 between 1955 and 1982, coinciding with the period of major shoreline alteration and channel excavation. Between 1960 and 2007, the annual water temperature of the SLR rose by 1.3°C (0.027°C year−1); none of the 10 coldest years and six of the 10 warmest years were observed since 1981. Temperature differences between the warmest and coolest years were greatest in spring and fall (by about 2.5°C); fish growing season (>5°C) was longer by 5 weeks and represented 20% more degree-days for the warmest years. In comparison with its tributaries, SLR water was slower to warm up in the spring but remained warmer in the fall: fish migrating seasonally between water masses could thus enhance or reduce their thermal budgets by 1–2°C daily. Northern pike recruitment years (year-class strength index [YCSI] values above the time series median) were best with June water levels >4.9 m IGLD85 (International Great Lakes Datum of 1985), combined with June air temperatures >18.6°C. For yellow perch, water temperatures >16.2°C in June alone explained six out of the eight best recruitment years in the time series. Conversely, an episode of massive carp mortality in 2001 exemplifies the inherent risk of using shallow flooded habitats for spawning when rapidly dropping levels coincide with hot, sunny weather. The effects of water temperature and level, singly and in combination, thus appear to be critical variables in determining successful fish recruitment in shallow riparian areas—areas which constitute the most important yet the most elusive fish spawning and nursery habitats.  相似文献   

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Summary Mussel populations in the Kerguelen Islands constitute an excellent model in which to study genetic differentiation, because of the exceptional geographic position of the islands with consequent very low external gene flow, the variety of biotopes that they occupy and their abundance there. Enzyme polymorphism and the electrophoretic variability of some loci have been studied in four populations of Mytilus desolationis Lamy 1936 and in four other populations of Aulacomya ater regia Powell 1957. In both species 67% of the loci were polymorphic. The electrophoretic variability of ACP-2, LAP-1, LAP-2, PGI and PGM in M. desolationis populations, and of ACP-2, LAP-1, LAP-2 and MDH in A. ater regia populations was analyzed by correspondence analysis. For M. desolationis the four populations studied were found to be heterogeneous; four loci contribute clearly to this differentiation. The populations from sheltered and exposed areas were distinguishable on the basis of the allelic frequencies of LAP-1 and LAP-2. The allelic frequencies of PGI and PGM allow further differentiation of the populations. For A. ater regia the four populations studied were distinguishable on the basis of the allele frequencies of ACP-2 and LAP-1 and the differences could not actually be related to their environmental conditions.  相似文献   

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