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1.
One flowering specimen of Ophrys bertolonii (s. str.) — a plant with a Circum-Adriatic distribution and hitherto unknown in other regions — was found on 7th May 2010 in the vicinity of Kunadacs (Central Hungary; N 47°00′ E 19°17′). The nearest known populations of this Mediterranean plant inhabit the Adriatic coast (ca. 450 km away) in Croatia, therefore this new occurrence represents a significant long distance dispersal event. The circumstances of the occurrence argue against introduction, but we can not decide now whether this new appearance is temporary or permanent. The permanent establishment of this strictly entomophilous plant requires the presence of its specific pollinator in the close neighbourhood of the habitat. However, no pollination was observed on the three flowers of the plant until 9th May, and one day later the stem had disappeared most likely due to grazing. Whatever the long-term fate of the plant is, this discovery represents a significant long distance (jump) dispersal event, and testifies to the dispersal ability of Ophrys species. Additionally, the appearance of a mature Adriatic plant in Central Europe fits well into the currently observed, climate change driven northward expansion of European orchids, therefore this finding most likely reflects a growing Mediterranean-like climatic influence in the region.  相似文献   

2.
Post-establishment spread of invasive species is a major determinant of their impact, but the spatial pattern and temporal rhythm of secondary spread are often poorly known or understood. Here we examine the spread of the European rockweed Fucus serratus over 1,500 km of shoreline after its initial discovery in Pictou, Nova Scotia (Canada) in 1868. Building upon earlier periodic surveys, we document the current distribution of this invader and provide a historic analysis of the invasion, including the integration of the recently-detected multiple introductions from Europe. The initial spread was rapid in the southern Gulf of St. Lawrence (6.0 km year−1), likely due to both natural spread in a favorable environment and the extensive regional shipping traffic at the time which linked Pictou to several key ports in eastern Canada and northeast USA. Later spread, especially along the Atlantic coast of Nova Scotia, was slower (recently 0.9 km year−1), but included several major jumps (~50–500 km), undoubtedly due to human-mediated transport. Although the spatial extent of the invasion has increased over the past 140 years, it has experienced several remarkable events: apparent local extinctions of northern satellite populations, a major retraction (100–150 km) along the northwestern limits of its continuous range, and stalled invasions at several points and times during its southward progression. Distributional data suggest that this invader is excluding congeners in shallow zones and possibly kelp species in deeper zones. Genetic data from one contact zone showed hybridization with native F. distichus but no evidence for introgression in migrating F. serratus. Hybridization and several other reproductive traits likely contribute to the competitive dominance of the invader in this environment.  相似文献   

3.
Three morphological characters were used to depict the position of the hybrid zone between two species of house mice,M. musculus Linnaeus, 1758 andM. domesticus Schwarz et Schwarz, 1943, across a vast area covering countries of the former Yugoslavia, Albania, Bulgaria and Greece. Quantitative approach based on a morphological index (MI), resembling the hybrid index widely used in allozyme-based genetic studies, was used. The zone crosses Slovenia south of the Sava River, and then follows the Dinaric Mts to Montenegro and northern Albania. Contrary to many previously published results, the zone was found to run parallel with northern borders of Albania and the former Yugoslavian Macedonia, about 150 km north of the Greek border, thus giving its course rather “shallow” appearance at this part of the Balkan Peninsula.  相似文献   

4.
Here we present the first observation of the impact of the invasive Caulerpa racemosa var. cylindracea on native photophilic sponge species in the Adriatic Sea, with special focus on Sarcotragus spinosulus. Caulerpa racemosa var. cylindracea is able to completely overgrow the sponge, developing an exceptionally thick canopy with a maximum measured density of 1,887 m of stolons m−2 and 40,561 fronds m−2. Necrosis of the sponge surface was significantly correlated with the algal dry biomass, frond number and stolon length. Dense algal canopy, penetration of the algal stolon and rhizoids into the sponge oscula and covering of the ostiae probably diminishes the seawater circulation through the sponge and consequently results in its smothering and even death. We suggest that chemotropism is the reason why C. racemosa penetrates the sponge oscula and establishes such dense canopy on the sponge.  相似文献   

5.
The invasive marine macroalga Sargassum muticum was recorded from Kilmore Quay, Co. Waterford, for the first time in the Republic of Ireland in 2001. It was found at several other places in that year and in subsequent years. An intensive survey was carried out from April 2003 to November 2003 to map the geographical distribution and spread of this invasive brown macroalga, and data on distribution were collected in subsequent years through 2006. This study indicated that S. muticum most probably arrived in the early or mid 1990s and has spread all around the Irish coastline colonising Co. Donegal for the first time in 2006. The results indicate that spreading is facilitated by boating and perhaps via shellfish transport. A rough rate of spread of 2–3 km year−1 has been calculated within one bay and for the Irish coastline of about 54 km year−1. Observations showed that S. muticum has been found growing in seagrass beds and in rock pools, which might have serious consequences for the biodiversity in rock pools and for the protective status of seagrass habitats. It is recommended that monitoring of S. muticum should continue, especially in areas of high amenity value and economic importance in order to observe possible effects on local flora and fauna, aquaculture, the seaweed industry and tourism.  相似文献   

6.

The opening of the Panama Canal?~?100 years ago created a migration pathway between the Caribbean Sea and the Pacific Ocean for euryhaline marine organisms that can cope with passage through 65 km of freshwater. The Atlantic Tarpon, Megalops atlanticus, a prized recreational-fishery species in its native geographic range, where it is considered “Vulnerable” by the IUCN Red List, is one species that has swum through the canal to the Tropical Eastern Pacific (TEP). Since Tarpon were first seen in the Pacific locks of the Panama Canal in the late 1930′s,?~?25 y after the opening of the canal, and large adults were subsequently observed in Panama Bay over many years, it has remained unclear whether this species has become established and is reproducing in the TEP. Here we review evidence showing that the Tarpon’s TEP geographic range now extends along?~?2600 km of the coastline (Guatemala to the Colombia/Ecuador border), and that adults are moderately common in the southern parts of that area. General ichthyoplankton surveys in the TEP over the last 50 year have not detected any Tarpon larvae. Small juveniles have been found throughout the main part of its TEP range, up to 700 km from the Panama Canal. As such fish typically are sedentary and have never been seen inside the Panama Canal, they most likely were spawned in the TEP. At present, nothing is known about the basic ecology of Tarpon in the TEP and possible effects it might have on native ecosystems there.

  相似文献   

7.
The age, growth, and population structure of the smooth clam Callista chione were determined from samples collected by hydraulic dredge and SCUBA at four locations in the eastern Adriatic during 2007 and 2008. The age of 436 clam shells was determined from internal growth lines present in shell sections, and the timing of growth line formation was ascertained from monthly collections of clams to occur between August and September when sea water temperatures were maximal. In addition, age of 30 older individuals was verified with acetate peels of polished and etched shell sections. Differences were apparent in the age structure and growth rates of clams collected from the four locations studied. Von Bertalanffy growth (VBG) curves obtained for clams from these locations were L t  = 72.4 (1−e−0.25(t − 2.68)) (Rab Island), L t  = 74.5 (1−e−0.15(t + 0.57)) (Pag Bay), L t  = 79.3 (1−e−0.34(t − 0.97)) (Cetina estuary), and L t  = 82.5 (1−e−0.11(t + 2.88)) (Kaštela Bay). The age of the clams ranged between 3 and 44 years; median clam ages were similar at three of the four locations (14, 12, and 12 years, respectively), but was significantly lower in the Cetina estuary (4 years). The VBG growth constants recorded from clams were within the range of values obtained for this species by previous authors. The observed local differences in population structure indicate different levels of exploitation and illustrate the need to establish long-term strategies for a sustainable exploitation of smooth clams in the Croatian Adriatic.  相似文献   

8.
North American oak species, with their characteristic strong episodic seasonal shoot growth, are highly problematic for clonal micropropagation, resulting in the inability to achieve a stabilized shoot multiplication stage. The potential for initiating and proliferating shoot cultures derived from Quercus alba, Q. bicolor and Q. rubra explants was investigated, and a micropropagation method for these species was developed. Branch segments from 6 to 7-year-old trees were forced-flushed and the forced shoots were used as source of explants for culture initiation. A consistent shoot multiplication stage was achieved, in 13 of the 15 genotypes established in vitro, although marked differences occurred in explants from different genotypes/species. The control of efficient shoot multiplication involved the culture of decapitated shoots in a stressful horizontal position on cytokinin-containing medium with a sequence of transfers within a 6-week subculture cycle, which was beneficial to overcoming the episodic character of shoot growth. During each subculture cycle, the horizontally placed explants were cultured on media containing 0.2 mg l−1 benzyladenine (BA) for 2 weeks with two successive transfers (2 weeks each) to fresh medium with 0.1 mg l−1 BA, giving a 6-week subculture cycle. The general appearance and vigor of Q. alba and Q. bicolor shoot cultures were improved by the inclusion of both 0.1 mg l−1 BA and 0.5 mg l−1 zeatin in the medium used for the second transfer within the 6-week subculture cycle. Addition of AgNO3 (3 mg l−1) to the shoot proliferation medium of Q. rubra had a significant positive effect on shoot development pattern by reducing deleterious symptoms, including shoot tip necrosis and early senescence of leaves. The three species showed acceptable in vitro rooting rates by culturing microcuttings in medium containing 25 mg l−1 indolebutyric acid for 48 h with subsequent transfer to auxin-free medium supplemented with 0.4% activated charcoal. Although an initial 5-day dark period generally improved the rooting response, it was detrimental to the quality of regenerated plantlets. However, activated charcoal stimulated not only the rooting frequencies, but it also enhanced plant quality, as evidenced by root, shoot and leaf growth.  相似文献   

9.
The southeastern border of the European Alps is not well resourced with high-resolution climate proxies and experiences a distinct climatic regime from the northern and western Alpine zones. Here, we present new high-resolution climatic proxies (AD 1907–2006) from ring widths and stable carbon (δ13C), non-exchangeable hydrogen (δ2H) and oxygen (δ18O) isotope ratios of cellulose extracted from Larix decidua tree rings, growing at the forest limit in the southeastern European Alps (Slovenia). δ13C, δ2H and δ18O are strongly (p < 0.001) and positively correlated with each other. June temperature has the strongest control on tree ring width (TRW), while later summer conditions (July–August) influence the stable isotope composition. All four proxies are strongly correlated (r > 0.4; p < 0.001) with summer temperature and also sunshine hours, while precipitation has less impact. A combination of TRW and δ13C provides the greatest potential for reconstructing past temperatures (June–August) with significant (p < 0.001) correlations with gridded temperatures extending across a very large part of southern and western Europe west of the Carpathian Mountains. The water isotopes (oxygen and hydrogen) record conditions in the Adriatic and Mediterranean, which are the source area for the air masses that bring precipitation to this region giving strong correlations with temperatures in southern Italy and the western part of the Balkan Peninsula. Combining proxies with different spatial and temporal signals allows the strength and spatial footprint of climate signals to be enhanced. These findings open new perspectives for climate reconstruction in the southeastern European Alps and Western Balkans.  相似文献   

10.
Gracilaria edulis, G. crassa, G. foliifera, and G. corticata are naturally occurring agarophytes of Indian waters. These agarophytes were evaluated for their agar contents using an improved process recently reported by us (US Patent 2005/0267296A1). The effect of different concentrations of NaOH in the alkali treatment was studied for optimizing the extraction conditions. These Gracilaria species of Indian waters produced agars, both native and alkali treated, with different properties confirming the heterogeneity of the agar polymers in this genera, as one would expect. Among these, G. edulis and G. crassa produced agar polymers having high gel strengths of 490 ± 8.16 and 800 ± 15.4 g cm−2, respectively, with 8% NaOH treatment as opposed the low gel strength agars that have been reported in the literature to date.  相似文献   

11.
A hyperthermophilic heterotrophic archaeon (strain WB1) was isolated from a thermal pool in the Washburn hot spring group of Yellowstone National Park, USA. WB1 is a coccus, 0.6–1.2 μm in diameter, with a tetragonal S-layer, vacuoles, and occasional stalk-like protrusions. Growth is optimal at 84°C (range 64–93°C), pH 5–6 (range 3.5–8.5), and <1 g/l NaCl (range 0–4.6 g/l NaCl). Tests of metabolic properties show the isolate to be a strict anaerobe that ferments complex organic substrates. Phylogenetic analysis of the 16S rRNA gene sequence places WB1 in a clade of previously uncultured Desulfurococcaceae and shows it to have ≤96% 16S rRNA sequence identity to Desulfurococcus mobilis, Staphylothermus marinus, Staphylothermus hellenicus, and Sulfophobococcus zilligii. The 16S rRNA gene contains a large insertion similar to homing endonuclease introns reported in Thermoproteus and Pyrobaculum species. Growth is unaffected by the presence of S0 or SO4 2−, thereby differentiating the isolate from its closest relatives. Based on phylogenetic and physiological differences, it is proposed that isolate WB1 represents the type strain of a novel genus and species within the Desulfurococcaceae, Thermogladius shockii gen. nov., sp. nov. (RIKEN = JCM-16579, ATCC = BAA-1607, Genbank 16S rRNA gene = EU183120).  相似文献   

12.
Some species are adapting to changing environments by expanding their geographic ranges. Understanding whether range shifts will be accompanied by increased exposure to other threats is crucial to predicting when and where new populations could successfully establish. If species overlap to a greater extent with human development under climate change, this could form ecological traps which are attractive to dispersing individuals, but the use of which substantially reduces fitness. Until recently, the core nesting range for the Critically Endangered Kemp's ridley sea turtle (Lepidochelys kempii) was ca. 1000 km of sparsely populated coastline in Tamaulipas, Mexico. Over the past twenty‐five years, this species has expanded its range into populated areas of coastal Florida (>1500 km outside the historical range), where nesting now occurs annually. Suitable Kemp's ridley nesting habitat has persisted for at least 140 000 years in the western Gulf of Mexico, and climate change models predict further nesting range expansion into the eastern Gulf of Mexico and northern Atlantic Ocean. Range expansion is 6–12% more likely to occur along uninhabited stretches of coastline than are current nesting beaches, suggesting that novel nesting areas will not be associated with high levels of anthropogenic disturbance. Although the high breeding‐site fidelity of some migratory species could limit adaptation to climate change, rapid population recovery following effective conservation measures may enhance opportunities for range expansion. Anticipating the interactive effects of past or contemporary conservation measures, climate change, and future human activities will help focus long‐term conservation strategies.  相似文献   

13.
Capabilities of cellulase production, using delignified bioprocessings of medicinal and aromatic plants, viz. citronella (Cymbopogon winterianus) and Artemisia annua (known as marc of Artemisia) and garden waste (chiefly containing Cynodon dactylon), by the six species of Trichoderma were comparatively evaluated. Among the members of Trichoderma studied, T. citrinoviride was found to be the most efficient producer of cellulases along with a high level of β- glucosidase (produced 102.4 IU g−1 on marc of Artemisia; 101.33 IU g−1 on garden waste; 81.86 IU g−1 on distillation waste of citronella and 94.77 IU g−1 on pure cellulose). Although T. virens was noticed to be the minimal enzyme producer fungus, it interestingly could not produce complete cellulase enzyme complex on any test waste or pure cellulose, except on marc of Artemisia, where it produced all three enzymes of the complex. Immediate reduction in pH was also noticed during fermentation in the case of pure polymer (cellulose) by all tested fungi, while it was delayed with delignified agrowastes. The pH profile varied with the substrate used as well as with individual species of Trichoderma. On the other hand, no alteration in pH with any species of Trichoderma was noticed when grown on marc of A. annua, which might be due to the buffering capacity of this marc.  相似文献   

14.
Recently recruited urchins from the same brood, but with different initial sizes, may respond differently to similar environmental factors. The aim of this study was to assess and compare the effects of starvation and diet on the survival, growth rates in size and weight, and gonad index among small and large sub-adult purple sea urchins, Strongylocentrotus purpuratus. Small urchins ranged from 7.3 to 7.8 mm and large urchins from 11.8 to 14.1 mm (test diameters). Two independent experiments were performed. In the first experiment, sea urchins were fed during 22 weeks on Egregia menziesii (ad libitum) and for only 1 day month−1 (starved condition). Feeding regime significantly affected survival, somatic growth rate in size and weight, and gonad index, with higher means in the ad libitum treatments than in starving conditions. A recurrent cannibalism event by conspecifics occurred in small sea urchins under starving conditions. In the second experiment, sea urchins were fed during 13 weeks ad libitum with four diets: kelp (E. menziesii), coralline algae (Bossiella orbigniana), eelgrass (Phyllospadix scouleri) and a mixed diet of the three species. Survival was not affected by diet or urchin size, but diet significantly affected somatic growth rate in size and weight and gonad index. Kelp promoted the highest growth rate (2.23 ± 0.21 mm month−1), the mixed diet produced an intermediate growth (1.26 ± 0.21 mm month−1), while the lowest values corresponded to coralline algae and the eelgrass (0.30 ± 0.12 and 0.10 ± 0.03 mm month−1, respectively, means ± SE). The mean growth rate of small urchins (averaging all diets) was higher than in large specimens (1.17 ± 0.37 and 0.77 ± 0.28 mm month−1, respectively).  相似文献   

15.
The Arctogadus glacialis is endemic to the Arctic Ocean and its apparently disjunct circumpolar distribution range from the Siberian coast through the Chukchi Sea and the Canadian Arctic to the shelf off NE Greenland. Records of A. glacialis are scarce in the European Arctic and here we present all available and reliable records of the species in the area. Altogether, 296 specimens of A. glacialis are reported from 53 positions in the European Arctic during the period 1976–2008. The specimens were registered off Iceland and the Jan Mayen Island, northwest and northeast of Svalbard, northeast in the Barents Sea, and south and east off Franz Josef Land. The additional records show that A. glacialis display a circumpolar and more continuous distribution than described before. In the European Arctic, A. glacialis has been caught at 155–741 m depth with the highest abundance at 300–400 m. We therefore suggest that A. glacialis is more associated to the continental shelves surrounding the Arctic Ocean than previously thought. The length–weight relation of A. glacialis is similar across the European Arctic.  相似文献   

16.
A TaqMan quantitative real-time polymerase chain reaction (qPCR) assay was developed for the detection and enumeration of three Pseudomonas species belonging to the mendocina sublineage (P. oleovorans, P. pseudoalcaligenes, and P. oleovorans subsp. lubricantis) found in contaminated metalworking fluids (MWFs). These microbes are the primary colonizers and serve as indicator organisms of biodegradation of used MWFs. Molecular techniques such as qPCR are preferred for the detection of these microbes since they grow poorly on typical growth media such as R2A agar and Pseudomonas isolation agar (PIA). Traditional culturing techniques not only underestimate the actual distribution of these bacteria but are also time-consuming. The primer–probe pair developed from gyrase B (gyrB) sequences of the targeted bacteria was highly sensitive and specific for the three species. qPCR was performed with both whole cell and genomic DNA to confirm the specificity and sensitivity of the assay. The sensitivity of the assay was 101 colony forming units (CFU)/ml for whole cell and 13.7 fg with genomic DNA. The primer–probe pair was successful in determining concentrations from used MWF samples, indicating levels between 2.9 × 103 and 3.9 × 106 CFU/ml. In contrast, the total count of Pseudomonas sp. recovered on PIA was in the range of <1.0 × 101 to 1.4 × 105 CFU/ml for the same samples. Based on these results from the qPCR assay, the designed TaqMan primer–probe pair can be efficiently used for rapid (within 2 h) determination of the distribution of these species of Pseudomonas in contaminated MWFs.  相似文献   

17.
Thailand border market is where the local Thais, Cambodians, Laotians, and Burmeses exchange their goods and culture at the border checkpoints. It is considered to be the source of aerial disease transmission especially for foreigners because it is always very crowded with people from all walks of life. Unhealthy air quality makes this area high risk of spread of airborne diseases. This study assessed airborne concentrations of bacteria and fungi in a border market to improve exposure estimates and develop efficient control strategies to reduce health risk. The density and distribution of airborne bacteria and fungi were investigated in the Chong Chom border market in Surin Province, Thailand. Eighteen air sampling sites were taken from outdoors and various work environments including indoor footpaths, wooden handicraft shops, electronic shops, the secondhand clothing shops, and fruit market areas. Exposed Petri plate method and liquid impinger sampler were used for sampling at the breathing zone, 1.5 m above the floor level, during weekend and holiday. Meteorological factors such as relative humidity, temperature, and light intensity were collected by portable data logger. The relative humidity was 67–73%, and temperature 29–33°C, and light varied between 18 and 270 Lux m−2. Gram-positive and Gram-negative bacteria were found at a mean value of 104 CFU m−3, and airborne fungi of 103 CFU m−3 were recorded. The highest concentration of culturable airborne microorganisms was found along the indoor footpath (9.62 × 104 CFU m−3 and 750.00 CFU/plate/h for impingement and sedimentation methods, respectively), the fruit market area (7.86 × 104 CFU m−3 and 592.42 CFU/plate/h for impingement and sedimentation methods, respectively), and the secondhand clothing shop (4.59 × 103 CFU m−3 and 335.42 CFU/plate/h for impingement and sedimentation methods, respectively) for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The lowest concentration of Gram-positive bacteria, Gram-negative bacteria, and fungi was found only at the outdoor area at 1.53 × 104 CFU m−3, 0.93 × 104 CFU m−3 and 0.80 × 103 CFU m−3 by means of impingement method and 136.67 CFU/plate/h, 69.25 CFU/plate/h, and 62.00 CFU/plate/h by means of sedimentation methods for Gram-positive bacteria, Gram-negative bacteria, and fungi, respectively. The most frequently present airborne bacteria were identified as Bacillus, Corynebacteria, Diplococcus, Micrococcus, Acinetobacter, Alcaligenes, Enterobacter, and spore former rods. Acremonium, Aspergillus, Cladosporium, Penicillium, and Sporotrichum were the most frequently found aerosol fungi genera. The distribution of airborne microorganisms correlated with relative humidity and light factors based on principal component analysis. In conclusion, the border market is a potential source of aerial disease transmission and a various hazards of bioaerosols for workers, consumers, sellers, and tourists. The bioaerosol concentration exceeded the standard of occupational exposure limit. Many major indicators of allergenic and toxigenic airborne bacteria and fungi, Acinetobacter, Enterobacter, Pseudomonas, Cladosporium, Alternaria, Aspergillus, and Penicillium, were found in the various market environments.  相似文献   

18.
A recent study concerning the reproductive biology of the garfish (Belone belone, L. 1761) has been carried out in the eastern part of the Adriatic Sea along the Croatian coastline. Specimens of the fish (N = 3,393) were collected over a 6-year period (2003–2008). Their length varied between 20.8 and 75.4 cm (mean ± SD = 38.3 ± 7.94). Female garfish were dominant in larger length groups being most apparent during the resting phase of sexual cycle and in the peak of the spawning period, occurring in April and May. The sexual ratio of all specimens was m/f = 0.98. Males were prevalent in March—at the beginning of the highest spawning activities. Fifty percentage of the garfish population sexually matured at 28.5 cm of total length. Males and females reached their sexual maturity at 28.0 and 31.5 cm of total length, respectively. Spawning began in January peaking during March to May. According to their maturity stages, gonad weight and the gonadosomatic index, males began to spawn one month earlier (April) than females (May). The mean batch fecundity of garfish was 1,242.46 ± 843.64 of matured oocytes per ovary. Matured oocyte diameters ranged from 1.223 to 4.283 mm with the mean value of 2.269 ± 0.332 mm.  相似文献   

19.
Population dynamics and zonation of the amphipods Bathyporeia pilosa and B. sarsi, co-occurring on some beaches, were studied through monthly sampling of eight cross-shore transects along the Belgian coast (October 2003–October 2004). Their biomass and production were assessed for the first time. Abundance and biomass of B. pilosa were ten times higher along western ultra-dissipative transects than along slightly more reflective, eastern transects. For B. sarsi (less prominent), differences between the two westernmost transects (2–5× higher) and all others were observed, whereas P/B ratio was comparable for all. B. pilosa could reach two times higher abundance and biomass and higher levels of production (max B. sarsi = 7,580 g m−2 y−1; max B. pilosa = 16,040 g m−2 y−1), while the species was nearly absent from the eastern transects. Continuous reproduction and recruitment with three relative peaks of the latter (February, July, October) were observed. Fecundity showed parallel temporal variation for both species, peaking in February and September–October. Interestingly, the July relative “recruitment” peak could not be explained by relative abundance of gravid females or fecundity, but was probably caused by adult mortality. Both species displayed comparable gonad production (B. pilosa: P g  = 0.73 mg/ind year; B. sarsi: P g  = 0.71 mg/ind year), but B. pilosa produced fewer yet larger embryos. Peak abundances were found at 436 ± 25 SD cm (B. pilosa) and 357 ± 40 SD cm (B. sarsi) above MLLWS, corresponding to a 40–62 m cross-shore distance between the peaks of both species. The occupied cross-shore range was larger for B. sarsi than for B. pilosa (35–54 m), for females than for males (15–23 m), and for adults than for juveniles of B. pilosa (5–8 m). Both species displayed many comparable life history features. Differences in abundance and biomass may be related to beach morphodynamics and zonation.  相似文献   

20.
Family Chenopodiaceae is an intriguing lineage, having the largest number of C4 species among dicots, including a number of anatomical variants of Kranz anatomy and three single-cell C4 functioning species. In some previous studies, during the culture of Bienertia cycloptera Bunge ex Boiss., carbon isotope values (δ13C values) of leaves deviated from C4 to C3−C4 intermediate type, raising questions as to its mode of photosynthesis during growth in natural environments. This species usually co-occurs with several Kranz type C4 annuals. The development of B. cycloptera morphologically and δ13C values derived from plant samples (cotyledons, leaves, bracts, shoots) were analyzed over a complete growing season in a salt flat in north central Iran, along with eight Kranz type C4 species and one C3 species. For a number of species, plants were greenhouse-grown from seeds collected from the site, in order to examine leaf anatomy and C4 biochemical subtype. Among the nine C4 species, the cotyledons of B. cycloptera, and of the Suaeda spp. have the same respective forms of C4 anatomy occurring in leaves, while cotyledons of members of tribe Caroxyloneae lack Kranz anatomy, which is reflected in the δ13C values found in plants grown in the natural habitat. The nine C4 species had average seasonal δ13C values of −13.9‰ (with a range between species from −11.3 to −15.9‰). The measurements of δ13C values over a complete growing season show that B. cycloptera performs C4 photosynthesis during its life cycle in nature, similar to Kranz type species, with a seasonal average δ13C value of −15.2‰. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

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