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1.
A new cycad,Leptocycas yangcaogouensis sp.nov.,was found in sediments from the Late Triassic in western Liaoning,China.The pinnately compound leaves(Pseudoctenis type)are screwed in a crown on the stem top.The leaflets are linear,with parallel veins and decurrent bases on the rachis.The leaf bases are persistent.The cataphylls intermix with the leaves.The female cone is ovoid in shape.The characteristics of the new plant are more similar to those of Leptocycas gracilis,a Triassic cycad from North America,but the new species differs from L.gracilis in the size of its stem(7–8 vs.3–5 cm in diameter,respectively),leaves(length×width 100×16 vs.30×7 cm,respectively)and leaf density along the stem(4–6 vs.1–2 bases/1 cm length,respectively).Both L.gracilis and L.yangcaogouensis,having leaves of the Pseudoctenis type,show a closer relationship to the extant Dioon of Zamiaceae.The present study provides evidence for the origin of the genus Dioon,which may have come from Leptocycas plants of the Triassic.It would be assumed that the extent cycads in Zamiaceae originate from the pteridosperms in the Late Paleozoic and have evolved through the stage of L.gracilis and L.yangcaogouensis in Late Triassic,and reaching the extant Dioon.  相似文献   

2.
Investigation of plant morphological features, pollen, and habitat have been made for two shrub species from Barrow, Alaska, namely Dryas integrifoila M. Vahl and Salix rotundifolia Trautv., both of which are endemic to the Arctic floristic area. The former species has small lanceolate or plate leaves, whereas the latter has rounded leaves with distinct veins, rich in vitamin C. Both have dwarf and sprawling habits. Pollen studies showed that the pollen grains of the two species are spheroidal to sub-spheroidal or prolate. The type of aperture was tricolporate; pollen size 26.3-31.3 μm; ornamentation finely reticulate under a light microscope (LM) and strlate-reticulate under a scanning electron microscope (SEM) for D. integrafoila and finely reticulate under the LM and SEM for S. rotundifolia. Comparisons were made between the pollen from the same species from Arctic collections with those from China and Japan. Investigation of pollen morphology of tundra plants can provide significant data for comparative studies of fossil pollen and for the reconstruction of paleovegetation and paleoclimate in the Barrow area.  相似文献   

3.
The topography and wettability of the underside of English weed (Oxalis pes-caprae) leaves and of their biomimetic replicas are investigated. Polyvinyl siloxane molds were cast from the leaves and then filled with an epoxy pre-polymer to produce replicas. The particular topographical structures of leaves and replicas were evaluated by optical microscopy and Scanning Electron Microscopy (SEM) analysis. The static wettability of leaves and replicas was assessed by contact angle measurements, while the dynamic wettability was characterized by estimating contact angle hysteresis and studying the dynamic behavior of impacting water droplets. A smooth glass slip and its replica were used as control surfaces. The replica moulding method used was able to transfer the characteristic pattern of irregular 100 μm - 200 μm × 60 μm convex papillae interspersed with stomata of the original leaf to the epoxy replicas. The static contact angle of 143°± 3° and the contact angle hysteresis of 2~ indicate that the underside of the English weed leaf is close to superhydrophobic. The lower contact angles (130° ± 4°) and higher hysteresis (31°) observed for the replica when compared with the original leaves were associated to an inaccurate replication of the chemistry and structures of the three-dimensional wax projections covering the plant surface. Also, trichomes in the original leaves could not be accurately reproduced due to their flexibility and fragility. Differences in wetting behavior were also evident from droplet impact experiments, with rebound regimes prevailing in the original leaves and regimes characterized by higher adhesion and larger dissipation predominating in the replicas. Nevertheless, the morphological features of the leaf transferred to the replica were sufficient to promote a clear hydrophobic behavior of the replica when compared with the smooth epoxy reference surface.  相似文献   

4.
The choice of a suitable species to translate pollution signals into a quantitative monitor is a fundamental step in biomonitoring plans. Here we present the results of three years of biomonitoring at a new coal power plant in central Italy using three different aquatic and terrestrial wildlife species in order to compare their reliability as sentinel organisms for genotoxicity. The comet assay was applied to the common land snail Helix spp., the lagoon fish Aphaniusfasciatus, and the green frog Rana esculenta sampled in the area potentially exposed to the impact of the power station. The tissue concentration of some expected pollutants (As, Cd, Ni, Pb, Cr) was analysed in parallel samples collected in the same sampling sites. The three species showed different values in the comet assay (Tail Intensity) and different accumulation profiles of heavy metals. Aphanius fasciatus showed an increasing genotoxic effect over time that paralleled the temporal increase of the heavy metals, especially arsenic, and the highest correlation between heavy metals and DNA damage. Helix spp. showed levels of damage inversely related to the distance from the source of pollution and in partial accordance with the total accumulation of trace elements. On the contrary, Rana esculenta showed a low capability to accumulate metals and had inconsistent results in the comet test. The fish appeared to be the most efficient and sensitive species in detecting chemical pollution. Overall, both the fish and the snail reflected a trend of increasing pollution in the area surrounding the power plant across time and space [Current Zoology 60 (2): 308-321, 2014].  相似文献   

5.
A new kind of marattialean raches are reported from the coal balls in Coal Seam No.7 in the upper part of the Taiyuan Formation (early Early Permian) from Taiyuan, Shanxi, China and are assigned to the genus Stipitopteris Grand'Eury (Psaroniaceae). The present specimens are different from all six reported species of the genus, and are therefore proposed as a new species: Stipitopteris shanxiensis. The raches of the new species are generally dorsi-ventrally flattened. The main raches usually exhibit scales of different forms on their surface. Beneath the epidermis is a zone of parenchymatous cells, some of which contain tannin-like contents. Inside this is a zone of small sclerenchymatous cells. Inward are the ground tissue and vascular bundles. The vascular bundles are continuous and are in two circles: the outer circle assumes a transversely elliptical shape with the gap and pinna trace, and the inner circle assumes a shallow C.shape with inrolled ends. The ground tissue located at the inner side of the vascular bundle is composed of thicker-walled parenchymatous cells. The cells of the ground tissue are vertically elongated in longitudinal sections. Subordered raches are smaller and have simpler structures than the main raches. The parenchyma zone beneath the epidermis is thinner, usually one to two cells wide and the sclerenchyma zone is usually absent. The scales are poorly developed and there is only one C-shaped vascular bundle. The new species is comparable to the crosiers of Psaroniaceae of the Euramerican Flora in some aspects, for example, it has a dorsi-ventrally flattened rachis and scales on the surface of the rachis. However, the other features and the preservative conditions of the present specimens indicate that they are not crosiers, but fully developed or mature raches. The new species is the first well-studied anatomically-preserved rachis of Psaroniaceae from the Cathaysian Flora and bears significance not only in understanding the anatomy and taxonomy of Psaroniaceae in the Cathaysian Flora, but also in the relationship between the Euramerican Flora and the Cathaysian Flora.  相似文献   

6.
7.
Chemical investigation of the organic solvent extract of Cretaceous Ginkgo coriacea Florin leaves by liquid chromatography-mass spectroscopy (LC-MS) and gas chromatography-mass spectrometry (GC-MS), analogous to those from extant leaves of Ginkgo biloba L., led to the detection of a group of natural flavonoids and other volatiles. The similarity of the chemical constituents in these two species of Ginkgo suggest that the secondary metabolism of extant G. biloba is close to that of the Cretaceous species. The remaining natural products may be one explanation why the leaves of the Cretaceous G. coriacea have been preserved morphologically in fossilization. The detection of flavonoids suggests that the leaves of G. coriacea experienced a mild post-depositional environment during their fossilization. This appears to be the oldest occurrence of flavonoids in plant fossils.  相似文献   

8.
We describe a new species from the family Salamandridae from northeastern Hunan Province of China based on morphological and molecular genetic evidences.The new species,Tylototriton liuyangensis,is a member of the T.asperrimus group,and shares a number of similarities with T.wenxianensis and T.broadoridgus.The dorsal surface of the new Tylototriton species is completely black,with nodule-like warts distributed evenly along the lateral margin of dorsal body,and there is no transverse striae between the warts.There are several diagnostic characters of the new species that differ from those of T.wenxianensis and T.broadoridgus as follows:(1)the interorbital space(IOS)is comparatively wide;(2)there is a bony ridge present on the dorsal head surface,running along the upper eyelids;(3)the space between axilla and groin(AGS)is comparatively large,with the mean male AGS approximately equal to 50%of the snout-vent length(SVL)and the mean female AGS being 53%of SVL;and(4)there is a small genital armature on the anterior angle of labial folds present inside the anal fissure of adult males during the breeding season.The result from the molecular phylogenetic analysis of the genus Tylototriton(including the type specimen of the new species)based on the complete DNA sequence of the mitochondrial ND2 gene(1035 bp)indicated that the new species was similar to T.wenxianensis,T.dabienicus,and T.broadoridgus,but formed an independent clade.This result was consistent with the morphological analysis above,supporting that the Liuyang Population represented a distinct species.  相似文献   

9.
Pachystoma is a small orchid genus of some four species ranging from India and southern China through Indochina, Malaysia and Indonesia to the Philippines, New Guinea and Caledonia. The type specimen of this new species was found in the herbarium of the Royal Botanic Garden, Edinburgh (E) mixed with unidentified specimens of Eulophia during the senior author's visit there late in June of 2001. Many specimens of Pachystoma, as well as some of Eulophia, lack leaves probably due to the similarity of their leaves to those of some kinds of sympatric grasses, such as Imperata, and therefore being overlooked (Schlechter 1914), or the absence of leaves during the period of flowering. In these cases, some species of Pachystoma were said to be saprophytic, and others misidentified as belonging to Eulophia.Acknowlegment The senior author wants to express his sincere thanks to the Kadoorie Farm & Botanic Garden for a grant to visit and study the orchid collections in European herbaria, to the curators of E for making the specimens available, to Dr. Y. Z. Wang for his kind help, and to Mrs. Cai Su-qing for preparing the drawing of this new species.  相似文献   

10.
Aims Leaf size, as one of the easier measured plant morphological traits, reflects response and adaptation of plants to environment and indicates functions and processes of ecosystem. When measuring leaf size (the leaf area, LA) on the field, the common accepted practice considers that the number of leaves picked off is often 10–20. However, what is the optimal number of leaves remains unknown. In this study, we attempt to determine how many leaves should be investigated when the leaf size of a tree is measured. Methods This study selected two dominant tree species (Schima superba, Ss and Liquidambar formosana, Lf) from a broadleaved evergreen and deciduous mixed forest in Jinhua Mountain of Zhejiang Province, eastern China. On the basis of sampling (>2 500 leaves for each tree) in five classes of the diameter of breast height (DBH) of tree species and at six directions for each individual, variations of LA in the two tree species are statistically analyzed. The optimal number of leaves, which can mostly represent the common leaf size feature, is further investigated. Important findings Mean LA of the evergreen tree Ss was smaller than that of the deciduous tree Lf. The former was (41.60 10.88) cm2 (16.74–100.80 cm2) and the latter was (57.65 19.35) cm2 (11.31–129.51 cm2). LA of Lf was significantly related to the DBH, but LA of Ss was not. LA of both trees in the middle DBH class (15–20 cm) was not significantly different from their means. LA of two trees have no significant correlations with the sampling directions, but LA at the east, west and bottom had no significant relationships with their means. Considering the representativeness and practicality in the field sampling, the priority of selecting leaves can target the bottom direction of middle diameter mature trees. Random sampling analysis indicated that, the optimal number of leaves for tree LA measurement is species specific. The optimal number of leaves for Ss is 40 and for Lf is at least 170, respectively. Therefore, when measuring leaf area in a forest community, the optimal sampling number of leaves should not be limited to 10–20 leaves. Under sufficient labor, material and time, more leaves should be measured. © Chinese Journal of Plant Ecology.  相似文献   

11.
12.
The carbon isotope discrimination (δ^13C) of leaves has been shown to be correlated with the transpiration efficiency of leaves in a wide range of species. This has led to δ^13C being used in breeding programs to select for improved transpiration efficiency. The correlation between δ^13C and transpiration efficiency was determined under well-watered conditions during the vegetative phase in six genotypes of lentil (Lens culinaris Medikus), six genotypes of chickpea (Cicerarietinum L.) and 10 cultivars of narrow-leafed lupin (Lupinus angustifolius L.). Biomass (dry matter) accumulation and water use (transpiration) varied among the genotypes in all three species and transpiration efficiency was 40% to 75% higher in the most efficient compared with the least efficient genotypes. However, δ^13C and transpiration efficiency were not significantly correlated in any of the species. This suggests that the δ^13C technique cannot be used in selection for transpiration efficiency in the three grain legumes (pulses) studied.  相似文献   

13.
The deposition of surface (farinose) flavonoids on aerial parts of some Primula species is a well-documented but poorly understood phenomenon. Here, we show that flavonoid deposition on the leaves and winter buds may contribute strongly to preventing freezing damage in these plants. The ice nucleation temperature of fairy primrose (Primula malacoides) leaves covered with natural flavone was approximately 6~C lower compared to those that had their flavone artificially removed. Additionally, farinose flavonoids on the leaves reduced subse- quent electrolyte leakage (EL) from the cells exposed to freezing temperatures. Interestingly, exogenous application of flavone at 4 mg/g fresh weight to P. malacoides leaves, which had the original flavone mechanically removed, restored freezing tolerance, and diminished EL from the cells to pretreatment values. Our results suggest that farinose flavonoids may function as mediators of freezing tolerance in P. malacoides, and exogenous application of flavone could be used to reduce freezing damage during sudden but predictable frost events in other plant species.  相似文献   

14.
The cheer pheasant Catreus wallichi is a globally threatened species that inhabits the western Himalayas. Though it is well established that the species is threatened and its numbers declining, updated definitive estimates are lacking, so in 2011, we conducted a survey to assess the density, population size, and threats to the species in Jhelum valley, Azad Kashmir, which holds the largest known population of cheer pheasants in Pakistan. We conducted dawn call count surveys at 17 points clustered in three survey zones of the valley, 11 of which had earlier been used for a 2002-2003 survey of the birds. Over the course of our survey, 113 birds were recorded. Mean density of cheer pheasant in the valley was estimated at 11.8±6.47 pairs per km2, with significant differences in terms of both counts and estimated density of cheer were significantly different across the three survey zones, with the highest in the Chinari region and the lowest, that is the area with no recorded sightings of the pheasants, in Gari Doppata. The total breeding population of cheer pheasants is estimated to be some 2 490 pairs, though this does not consider the actual area of occupancy in the study area. On the whole, more cheer pheasants were recorded in this survey than from the same points in 2002-2003, indicating some success in population growth. Unfortunately, increasing human settlement, fires, livestock grazing, hunting, and the collection of non-timber forest products continue to threaten the population of cheer in the Jhelum valley. To mitigate these potential impacts, some degree of site protection should be required for the conservation of cheer pheasants in Pakistan, and more effective monitoring of the species is clearly needed.  相似文献   

15.
The present paper reports in detail 12 species and varieties of trombiculid mites. Of these eight are believed to be new to science. Besides, a new genus is also created to accommodate certain species which are incompatible with other species originally found in the same genus. The 12 species and varieties are distributed in three subfamilies, and their names are as follows:  相似文献   

16.
The present paper deals with four species belonging to three genera, in which a genus (Paraletabo gen. nov.) and four species are described as new to science, a genus (Sophianus Distant) is recorded for the first time from China. The type specimens are deposited in the Department of Biology, Nankai University. The new genus and new species are briefly diangnosed as follows.  相似文献   

17.
The present paper deals with four species of the genus Neopodocinumoff scarabaeid beetles in China, among them Neopodocinum sinicum and N.gunnanense are new to science, the deutonymph of N. dehongense is descri-bed for the first time, and N. vanderhammeni is collected in southwestChina for the first time. The type materials are deposited in the Depart-ment of Parasitology, Guiyang Medical College.Keys to the females and malesof 6 known Chinese species of the genus Neopodocinum are appended.  相似文献   

18.
A new species, Amolops mahabharatensis sp.nov., is described from Mahabharat range(middle mountain) of Nepal. The new species is a member of the A. marmoratus group and is distinguished from its congeners using morphological and molecular data.The new species is diagnosed by having numerous warts on dorsum and flanks, dorsal body greyish olivebrown/light brown, presence of vomerine teeth series,presence of a pair of subgular vocal sacs in males and tadpole with Ⅲ:5+5/1+1:Ⅱ– labial tooth row. In addition,evidenced by the phylogenetic and morphological analyses in this study, Amolops nepalicus is shown to be a valid species. A molecular phylogenetic analysis based on 16 S ribosomal gene for six members of the A. marmoratus group suggested that the new species is sister to a clade containing A. nepalicus and A. panhai.The uncorrected genetic divergences between the new species and its closest congeners A. nepalicus, A. panhai and A. marmoratus based on 16 S rRNA gene were 10.5%,11.6%, and 8.6% respectively. The new species showed wide distribution in the Mahabharat range of Nepal.  相似文献   

19.
Nepal is located in the central part of the greater Himalayan range with a unique series of mountain chains formed by recent mountain building geological events. As one of the youngest mountains in the world it contributes to diversity of plants and also provided barriers to and corridors through which plants migrated during the ice ages. The higher altitudinal variation with the high mountains, deep river valleys and lowland plains combine with the effects of the summer monsoon and dry winter result with an extraordinary diversity of ecosystems including flora and fauna in a relatively small land area. The existing checklists for Nepal record some 6000 species of flowering plants and about 530 ferns. However, the botanical experts estimate that numbers may go up to 7000 when the poorly known remote regions are fully explored. The information on plant endemism in Nepal Himalaya is not adequately known as Nepal is still struggling to complete long awaited Flora of Nepal project. Endemic species are confined to specific areas and are the first to be affected by land use and other global changes. We sought to explore the spatial distribution of endemic plant species in Nepal in relation to the consequences associated with climatic and geologic changes over time in the region with the help of published literature. It was found that the endemism showed marked spatial variation between open moist habitat and dry inner valleys, the former with higher endemism. The updated records showed 312 flowering plant species to be endemic to Nepal with higher endemism around the elevation of 3800e4200 m at sea level. The recent human population explosion, intensified deforestation, habitat fragmentation and modern day environmental changes are posing greater threats to endemic plant in Nepal. The conservation status and threats to these peculiar species are unknown. Nevertheless, environmental degradation and high poverty rates create a potent mix of threats to biodiversity in this landscape.  相似文献   

20.
A population of Japalura from Yunnan Province, China, previously assigned to Japalura splendida, is described as a new species. The new species has been recorded between 1 138–2 500 m in the Nu River drainage between the towns of Liuku and Binzhongluo, and on the lower western slopes of the Nushan and eastern slopes of the Goaligongshan. The new species can be distinguished from other species of Japalura, except J. dymondi, by the following combination of characters: exposed tympani, prominent dorso-lateral stripes, and small gular scales. It is very similar with but differs from J. dymondi by having smooth or feebly keeled dorsal head scales, three relatively enlarged spines on either side of the post-occiput area, strongly keeled and mucronate scales on occiput area and within the lateral stripes, back of arm and leg green, higher number of dorsal-ridge scales(DS) and fourth toe subdigital scales(T4S). A principal component analysis of body measurements of adult male specimens of the new species and J. dymondi showed principal component 1 loading highest for upper arm length, fourth toe length and snout to eye length and principal component 2 loading highest for head width, head length and fourth toe length.  相似文献   

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