The first Pleistocene fossil records of Urtica kioviensis Rogow. (Urticaceae) and Potamogeton sukaczevii Wieliczk. (Potamogetonaceae) in the British Isles

Vegetation History and Archaeobotany - Seeds of the extant Urtica kioviensis Rogow. (Urticaceae) and endocarps of the extinct Potamogeton sukaczevii Wieliczk. (Potamogetonaceae) were recorded in...     

Pollen Morphology of Impatiens L. (Balsaminaceae) and Its Taxonomic Implications

Two forms of pollen morphology of Impatiens L. (Balsminaceae) have been described before: 3-colpate and 4-colpate pollen grains. Pollen grains of 13 species of Impatiens on Mt. Omei were examined under SEM for the first time and both forms were observed here, which imply the diversity of species in this region. Of the two forms, 3-colpate one is quite similar to that of the genus Hydrocera Blume (Balsaminaceae) in external morphology. This relation also exists between the 3-colpate pollen group and Hydrocera in habit, habitat, and distribution, etc. It is supposed that the group with 3-colpate pollen type is a natural one, and may have a close relationship with Hydrocera. The pollen morphology is of important significance in classification of the taxa and evaluation of systematic position in the fami-ly balsaminaceae.     

鹅掌楸属种间杂种与亲本花粉壁的超微结构的比较观察

以杂种鹅掌楸及其亲本中国鹅掌楸(Liriodendron chinense)和北美鹅掌楸(L.tulipifera)为材料,研究花粉形状及花粉壁的超微结构.结果表明,杂种与亲本间花粉壁超微结构具有明显的差异,它们可作为种间及杂种与亲本的识别与区分的依据.从杂种鹅掌楸与双亲的花粉壁的纹饰的遗传关系来看,前者花粉壁表面皱疣状隆起的纹饰表明,北美鹅掌楸花粉壁纹饰特征在杂种鹅掌楸中得到充分表现.     

Environmental inferences and chironomid-based temperature reconstructions from fragmentary records of the Weichselian Early Glacial and Pleniglacial periods in the Niederlausitz area (eastern Germany)

We inferred past climate conditions from lacustrine sediments intercalated in Weichselian Early Glacial and Early Pleniglacial fluvial and aeolian sediments, exposed in two opencast lignite mines from the Niederlausitz area (eastern Germany). A chronology was established using radiocarbon and luminescence dating methods. Both lithology and chironomid fauna indicate that the former shallow lakes were situated on a floodplain. Palaeotemperature estimates calculated from the fossil chironomid-assemblages of the Early Glacial lacustrine deposit indicate mean July air temperatures of ca. 15 °C, which is in line with results derived in earlier studies from the Niederlausitz area and from northwestern Europe. The Early Pleniglacial lacustrine deposits consist of an organic-rich gyttja, intercalated with sand and silt lenses. The chironomid-assemblages show that a shallow meso- to eutrophic lake was present at the study site, and chironomid-inferred palaeotemperature estimates indicate an abrupt decline in July air temperatures from 15–16 °C to ca. 13 °C. In combination with other proxies from the same record, this suggests a Dansgaard/Oeschger like climate event.     

The use of historical analogues for interpreting fossil pollen records

Modern vegetational analogues of palaeo-landscapes, which could be useful for interpreting fossil pollen assemblages, are often not available, because increased human impact all over the world has altered the vegetation, and the way in which vegetation is recorded by pollen assemblages, including changes in species composition, pollen production, dispersal and sedimentation. Historical maps, survey records and other sources may, however, provide vegetation data for periods prior to this increased human impact, and these may be compared with pollen assemblages from the same period to provide historical analogue data sets. In this paper we review the use of historical analogues in pollen analysis to describe past vegetation patterns in relation to soil properties, climate and fire regimes, and to reconstruct past land use changes, forest composition and species range limits. The methods used include qualitative interpretations, analogue matching, ordination techniques and regression. Because the historical data sources were originally created for other purposes, they may lack the precision or detail needed for quantitative analysis.      

The influence of hybridization on epidermal properties of birch species and the consequences for palaeoclimatic interpretations

The Fennoscandian birch population primarily consists of Betula nana, B. pendula and B. pubescens ssp. czerepanovii, the Mountain birch. Frequent hybridization between the Mountain birch and B. nana generates a wide range of genotypic and phenotypic plasticity in the subarctic birch zone of Fennoscandia. Phases of subarctic conditions prevailed during the Late Glacial in large parts of NW Europe, and palynological as well as macrofossil analysis provide some evidence for the occurrence of birch hybrids during these intervals. Leaves from genetically controlled specimens of Betula pendula, B. pubescens ssp. czerepanovii, B. nana and the hybrids B. pubescens ssp. czerepanovii × nana and B. nana × pubescens ssp. czerepanovii are investigated for their specific characteristics of the epidermis morphology. Frequency and size of epidermal cells and stomata reveal a close affinity of both hybrids to B. nana and allow a differentiation of the intermediate forms between B. nana and the Mountain birch. With respect to palaeoatmospheric CO₂ reconstructions based on stomatal index, epidermal analysis shows that a possible occurrence of hybrids in fossil leaf assemblages has no profound consequences for combined species records. However, the significant differences observed in B. nana demand the separation of this species. A comparison of the cuticle properties of B. pendula and B. pubescens from Finnish Lapland and leaf material from The Netherlands reveals a divergence of the stomatal index that may be due to differences in day light length.     

中国蓼科萹蓄属植物花粉形态及其分类意义

利用扫描电镜研究了中国萹蓄属(Polygonum) 13种、1变种、1变型植物的花粉形态.结果表明,中国萹蓄属植物的花粉粒为长球形或超长球形,具三孔沟,外壁纹饰可分为4种类型(1)花粉粒表面具细网状纹饰;(2)花粉粒表面具颗粒纹饰;(3)花粉粒表面仅两端具颗粒纹饰,其余部分光滑;(4)花粉粒表面仅沟间区两端肩部光滑,其余部分具颗粒纹饰.根据花粉形态类型,结合该属植物的习性、叶柄基部及花柄上关节的有无、花柱和柱头的数目以及瘦果形态等特征,参照前人的研究处理意见,将中国萹蓄属植物划分为4个组,即小灌木组section Fruticulosae (Boiss.) F.Z.Li et Y.T.Hou,stat.& comb.nov.、萹蓄组section Polygonum、丝茎萹蓄组section Pseudomollia Boiss.和铁马鞭组section Plebeia Tzvel..     

A Systematic and Evolutionary Study of Zizania L. (Gramineae) Pollen Morphology

This paper deals with pollen morphology of Zizania L. and its relatives. A total of 7 genera, 13 species, 3 varieties and 1 form were examined under light microscope and scanning electron microscope. The results are as follows: 1. The genus Zizania belongs to tribe Oryzeae as shown by pollen characters, i, e. subspheroidal to ovoid in shape, monoporate, exine two-layered, with minute granules under LM. 2. The evolutionary trend of these taxa seems to be from minute granules free (Zizania latifolia, Z. texana, Zizaniopsis milicea and Oryza sativa) to minute granules aggregated in a group of 2-4 (many) (Zizania aquatica, Z. palustris, Leersia hexandra etc.). The genus Zizania may be derived from the ancient stock which has also given rise to the genus Oryza, and therefore parallel evolution may have taken place in Oryzeae, i. e. from perennial species to annual species in Zizania in one line, and from the genus Oryza to Leersia, Chikusichloa etc. in the other. 3. The characters of pollen morphology under LM and SEM support the division of the genus, Zizania into 4 species, 2 subspecies in the world, i. e. Z. latifolia (Griseb.) Turcz. ex Stapf, Z. texana Hitchc., Z. aquatica subsp. aquatica, Z. aquatica subsp. brevis (Fassett) S. L.Chen, Z. palustris subsp. palustris, and Z. palustris subsp. interior (Fassett) S. L. Chen.     

The Pollen Morphology in Relation to the Taxonomy and Phylogeny of Fagaceae

The present paper deals with the pollen morphology of 103 species belonging to sixgenera-Castanea, Castanopsis, Lithocarpus, Quercus, Fagus and Trigonobalanus in threesubfamilies-Castaneoideae, Quercoideae and Fagoideae. All pollen grains were examinedunder light microscope and scanning electron microscope, and those of some species were ex-amined under transmission electron microscope. The results may be summarised as follows:1. Pollen morphology of Fagaceae, seems to support division of the family into threesubfamilies. Fagoideae, Castaneoideae and Quercoideae.2. Four types of pollen grains are recognized in Fagaceae:1) Fagus-type (representative genus: Fagus): pollen granis are oblate-sphaeroidal,(31.5-39.9) x (35.7 46.2) μm in size, 3(-4)-colporate, peritreme or goniotreme, granulate-ornate under LM., granulate or verrucate under SEM.2) Trigonobalanus-type (T. doichangensis): pollen grains are suboblate-sphaeroidal,(23.1-29.4) ×(25.2-29.4) μm in size, 3-colporate, goniotreme, obscurely granulate-ornateunder LM, densely granulate or verrucate under SEM.3) Quercus-type (Quercus): pollen grains are subspheroidal-subprolate, (21-44.3)× (16.8-39.9) μm in size. 3-colporoidate (-3-colpate), peritreme, crassgranulate or finely-gra-nulate under LM, tuberculate verrucate or spinate under SEM.4) Castanea-type (including Castanea, Castanopsis, Lithocarpus): Pollen grains areprolate-supraprolate, (14.7-23.1)×(10.5-16.8)μm in size; 3-colporate, peritreme, obscu-rely ornate or subpsilate, under LM, rugulose, striate-rugulate or crass-striate under SEM.3. Pollen grains of Cyclobalanopsis age very similar to those of Quercus, and there-fore we support the treatment of Cyclobalanopsis as a subgenus of Quercus.4. On the basis of shape, type of aperture and exine structure, pollen of Trigonobalanusis distinguishable from those of the other genera in Fagaceae and it may be a new type of Fagaceae;5. On the basis of pollen morphology, morphological characters and geological stratification a scheme of phylogeny of Fagaceae is here presented.     

Continental molluscs of the fossil site Sandelzhausen (Miocene; Upper Freshwater Molasse from Bavaria) and their value for palaeoecological assessment

The continental mollusc fauna of Sandelzhausen (Southern Germany, Early/Middle Miocene, MN5) is presented and shown to consist of 66 snail and 3 bivalve taxa. Previous ecological interpretations were partly based on poorly preserved material and are shown to be erroneous. Within a series of quantitative samples, ecologically four mollusc communities can be distinguished (two each for terrestrial and freshwater molluscs), highly indicative of ecological conditions and changes in the landscape surrounding the fossil site as well as the locality itself. Open scrub-lands with temporary waters, as indicated by forms such as Granaria and the dominance of lymnaeids, are steadily replaced with damp forests with abundant litter and rotting wood surrounding a perennial lake with small tributaries. These more favorable conditions are indicated by an overall increase of mollusc diversity, rising abundance of planorbids, and presence of restricted forms such as Drepanotrema (intolerant to droughts) as well as certain forest dwellers such as Gastrocopta and hygromiids. Molluscs are highly sensitive to environmental changes, which is reflected in the fossil record of Sandelzhausen.      

Identification of cultivated Pandanus and Colocasia in pollen records and the implications for the study of early agriculture in New Guinea

Pollen records from the island of New Guinea, spanning the last 60 000 years, show a vegetation system sensitive to global climate change and strongly influenced by anthropogenic activity. The evidence for anthropogenic activity in pollen diagrams has focused on indirect indicators such as forest clearance, burning and increases in arable weeds. Tracing individual cultivars has proven to be very difficult as the major cultivated plants, in this case dominated by root crops, have low pollen production, are insect-pollinated or are harvested before flowering occurs. The identification of some cultivars is further restricted by limited information on pollen morphology. The pollen morphology of selected species from two genera (Pandanus and Colocasia), known to include important cultivated species, have been studied. Five pollen taxa are recognised after examination by light microscopy and scanning electron microscopy. It is shown that these can be easily distinguished on the broad criteria of pollen class, grain size and size of echini. The taxonomic and dispersal characteristics of the pollen morphology of these taxa are discussed and the implications of improved identification of cultivated species in late Quaternary pollen records are considered.     

Ectophoma iranica sp. nov. and new hosts and records of Allophoma spp. in Iran

A survey was conducted to identify fungi associated with leaf diseases of ornamental herbs, including Christ plant, dracaena, rose geranium, rose periwinkle and treasure flower, in Ahvaz, southwestern Iran. Twenty‐five symptomatic herbs were collected and studied, which led to the isolation of seven Phoma‐like strains belonging to four taxa. These fungi were characterised based on DNA sequence data for the partial large subunit 28S nrDNA (LSU‐D1/D2), the internal transcribed spacer 1 and 2 and 5.8S nrDNA (ITS) and part of the β‐tubulin (tub2) gene regions. A multi‐locus‐based phylogeny, in combination with morphology, allowed for the identification of Allophoma hayatii, A. labilis, A. tropica and a novel species of the genus Ectophoma. Ectophoma iranica sp. nov. is morphologically and genetically distinctive from previously described species. In pathogenicity tests, the two strains of E. iranica (CBS 144681 and IRAN 3354C) caused leaf spot symptoms on leaves of Catharanthus roseus. New host plant species and records for A. hayatii, A. labilis and A. tropica are reported, plus further emended characterization of A. hayatii.     

物参属花粉形态及其分类学意义

首次报道了兰科的手参属Ｇｙｍｎａｄｅｎｉａ国产５种植物花粉形态的研究结果,并与邻近的兜被兰属Ｎｅｏｔｔｉａｎｔｈｅ花粉进行了对比研究。前者花上块形状大多不规则,少数为三棱体形;而后者花粉小块大多形状为三棱锥体形,少数形状不规则。手参属花粉外壁表面具很细微的小穿孔、皱波状,小穴和小穿孔与沟渠状纹饰共存,或沟渠状等。而兜被兰属外壁表面纹饰明显,具有５种类型：（１）小穿孔,（２）表面近光滑,（３）沟渠状     

Intervals for the assessment of measurement agreement: Similarities,differences, and consequences of incorrect interpretations

Several intervals have been proposed to quantify the agreement of two methods intended to measure the same quantity in the situation where only one measurement per method and subject is available. The limits of agreement are probably the most well‐known among these intervals, which are all based on the differences between the two measurement methods. The different meanings of the intervals are not always properly recognized in applications. However, at least for small‐to‐moderate sample sizes, the differences will be substantial. This is illustrated both using the width of the intervals and on probabilistic scales related to the definitions of the intervals. In particular, for small‐to‐moderate sample sizes, it is shown that limits of agreement and prediction intervals should not be used to make statements about the distribution of the differences between the two measurement methods or about a plausible range for all future differences. Care should therefore be taken to ensure the correct choice of the interval for the intended interpretation.     

虾塘中新生残饵的N,P营养物质溶出速率及其变化规律研究

通过实验模拟的测定结果 ,估算了新生残饵对虾塘养殖环境的可能影响程度 .结果表明 ,两种新生残饵的N、P营养物质溶出速率及其TN与TP、IP与TP比值 ,随其生成时间的延长均有较大幅度变化 ,且变化趋势相近 .贻贝新生残饵因其分解速率较快 ,故对养殖水体短期影响较大 ,但其总体影响却并不大于配合饵料 .新生残饵是对虾养殖水环境及其临近浅海环境的主要污染源 .     

Insight into the phylogeny of African Clariidae (Teleostei, Siluriformes): implications for their body shape evolution, biogeography, and taxonomy

The phylogenetic relationships among Clariidae species (Teleostei, Siluriformes) were assessed using 563 nucleotides of the cytochrome b mitochondrial gene. We included 32 Clariidae species representative of seven genera in our analysis. Hetropneustes fossilis (Heteropneustidae) and Clarotes laticeps (Claroteidae) were used as outgroups. The molecular data identified two evolutionary lineages that correspond on one hand to African species and on the other hand to Asian species. Morphological and osteological evolution in Clariidae did not follow an orthogenetic series. Species with robust body, strong ossified head, and large adipose fin were not ancestral ones and eel-like species were not phylogenetically related and represent independent adaptation to life in mud. Adaptation to life in deep water occurred two times independently in lake Tanganyika (with Dinotopterus cunningtoni) and in Lake Malawi (with Bathyclarias species). Molecular dating using a molecular clock of 1% divergence per million years and a comparison with fossils records allowed an estimate of the timing of cladogenesis within the species studied. The Clariidae family originated in Asia 50 MY ago but contemporary African and Asian studied species originated from a common ancestor that was present on the Arabian plate about 15 MY ago. Systematic implications of these results are also discussed.     

Pollen Morphology and Epidermal Characters of Leaves in Convallarieae (s. l.)

The tribe Convallarieae (sensu Krause 1930) consists of 7 genera, i.e. Convallaria, Speirantha, Reineckia, Theropogon, Tupistra, Rohdea and Aspidistra, but now generally recognized as two tribes, Convallarieae (the former 4 genera) and Aspidistreae (the rest). Observed in this work were pollen morphology of 17 species and epidermal characters of leaves of 12 species. All the 7 genera are covered in observations. Pollen grains in Convallarieae (s. str.) are all monosulcate and boat-shaped (Plate 1: A-F). The exine is rather uniformly microperforate (Plate 1: A-F); only Theropogon is exceptional in this respect: it has rugulate exine (Plate 1: O, P). Tang and Zhang (1985) have pointed out the heterogeneity of Theropogon in this tribe. Pollen morphology in the tribe Aspidistreae is widely variable. The genera Tupistra and Rohdea were shown to have monosulcate and boat-shaped pollen grains. Their exine is perforate or reticulate (Plate 1: G-N). Pollen grains in the genus Aspidistra, however, are nonaperturate and spheroidal. The exine in the genus varies from crass-rugulate, variously gemmate to tuberculate-baculate (Plate 2; A-H). The pollen morphology of Aspidistra is therefore distinctly different from that of Tupistra and Rohdea, which supports the Nakai's (1936) establishment of the tribe Rohdeae for Tupistra and Rohdea. Therefore, Krause's Convallarieae is reasonably divided into at least three tribes, Convallarieae (Speirantha, Convallaria, Reineckia and Theropogon), Aspidistreae (Aspidistra) and Rohdeae (Rohdea and Tupistra). The pollen characters of all the 7 genera are shown in Table 1. The evolutionary trends of pollen morphology (aperture and exine) in the three tribes are discussed and our major view-points are shown in Fig. 1. Observations on epidermal characters of leaves show that in the Convallarieae (s. 1.) stomatal apparatuses are all anomocytic; cuticular layer on the upper epidermis is mainly striatethickened or rather uniformly thickened (Plate 2: J--P; Plate 3: A-C, F-N), whereas in the genus Convallaria the cuticular layer is squamosely thickened (Plate 2: I; Plate 3: D, E).The epidermal characters of leaves in the 7 genera are summarized in Table 2.     

The chironomid fauna of four shallow,humic lakes and their representation by subfossil assemblages in the surficial sediments

A comparison of the present chironomid fauna of four shallow, humic lakes with the subfossils of surficial sediments is made. The chemistry and benthos of the lakes investigated varied greatly. Results indicate a reasonable correlation between biocenoses and thanatocenoses, but a marked under-representation ofProcladius is apparent. It is suggested that, at least in shallow, humic lakes,Procladius be excluded in attempts to reconstruct chironomid communities from subfossils.