Platanus Species Research Articles

Effects of climate change on Platanus flowering in Western Mediterranean cities: Current trends and future projections

Ornamental trees can reduce some of the negative impacts of urbanization on citizens but some species, such as Platanus spp., produce pollen with high allergenic potential. This can exacerbate the symptomatology in allergic patients, being a public health problem. Therefore, it would be relevant to determine the environmental conditions regulating the flowering onset of the Platanus species. The aims of this study were to use aerobiological records for modelling the thermal requirements of Platanus flowering and to make future projections based on the effects that climate change could have on it under several possible future scenarios. This study was conducted in Badajoz and Malaga, two Western Mediterranean cities with different climate conditions. In the first step, several main pollen season definitions were applied to the aerobiological data and their onset dates were compared with in situ phenological observations. The main pollen season definition that best fitted the Platanus flowering onset was based on the 4th derivative of a logistic function. This definition was used as a proxy to model the thermal requirements of the Platanus flowering onset by applying the PhenoFlex statistical framework. The errors obtained by this model during the external validation were 3.2 days on average, so it was fed with future temperature estimations to determine possible future trends. According to the different models, the flowering onset of Platanus in Badajoz will show heterogeneous responses in the short and medium term due to different balances in the chilling-forcing compensation, while it will clearly delay in Malaga due to a significant delay in the chilling requirement fulfilment. This may increase the chances of cross-reactivity episodes with other pollen types in the future, increasing its impact on public health.

Assessment of the Relationships Between Leaf Characteristics with Air Pollutants: A Case Study on Oriental Plane (Platanus orientalisL.) and Caucasian Hackberry (Celtis caucasicaWilld.)

AbstractBackgroundPlants are sensitive to air pollution by altering their vital processes such as growth or photosynthesis. Leaf characteristics reflect the adaptive mechanism of plants to their environment. This mechanism is demonstrated through changes in anatomical, morphological, and physiological characteristics relative to environmental changes.MethodsSamples were taken from 2 species ofPlatanus orientalisL. andCeltis caucasicaWilld. in 10 urban forests of Tehran, Iran. In each study area, 50 leaves were collected from different directions of the canopy of each tree, and their area was measured by a leaf area meter instrument in a laboratory. Leaf moisture and specific leaf area (SLA) were also calculated. The data of air pollutants were obtained from the nearest pollution measurement stations to each study location.ResultsThe average percentage of moisture forP. orientalisandC. caucasicawas calculated as 49.6% and 41.9%, respectively. The averages of SLA were estimated 9.2 and 6.5 cm2/g, respectively. The average leaf area was 36 and 6.04 cm2, respectively. The correlation between quantitative variables of leaf (leaf area and SLA) and air pollutant appeared in both study species, only there was a significant negative relationship between leaf area and O3. This relationship was stronger inC. caucasica(R2= −0.78).ConclusionThe results of this research showed that both species showed similar behavior against air pollutants, butC. caucasicashowed more reaction.

Interlaboratory Performance of a Real-Time PCR Method for Detection of Ceratocystisplatani, the Agent of Canker Stain of Platanus spp.

Ceratocystis platani (CP), an ascomycetous fungus, is the agent of canker stain, a lethal vascular disease of Platanus species. Ceratocystis platani has been listed as a quarantine pest (EPPO A2 list) due to extensive damage caused in Southern Europe and the Mediterranean region. As traditional diagnostic assays are ineffective, a Real-Time PCR detection method based on EvaGreen, SYBR Green, and Taqman assays was previously developed, validated in-house, and included in the official EPPO standard PM7/14 (2). Here, we describe the results of a test performance study performed by nine European laboratories for the purpose of an interlaboratory validation. Verification of the DNA extracted from biological samples guaranteed the high quality of preparations, and the stability and the homogeneity of the aliquots intended for the laboratories. All of the laboratories reproduced nearly identical standard curves with efficiencies close to 100%. Testing of blind-coded DNA extracted from wood samples revealed that all performance parameters—diagnostic sensitivity, diagnostic specificity, accuracy and reproducibility—were best fit in most cases both at the laboratory and at the assay level. The previously established limit of detection, 3 fg per PCR reaction, was also validated with similar excellent results. The high interlaboratory performance of this Real-Time PCR method confirms its value as a primary tool to safeguard C. platani-free countries by way of an accurate monitoring, and to investigate the resistance level of potentially canker stain-resistant Platanus genotypes.

Moderate to Elevated Atmospheric CO2 During the Early Paleocene Recorded by Platanites Leaves of the San Juan Basin, New Mexico

AbstractThroughout the Phanerozoic, estimated CO2 levels from CO2 proxies generally correlate well with independent estimates of temperature. However, some proxy estimates of atmospheric CO2 during the Late Cretaceous and early Paleocene are low (<400 ppm), seemingly at odds with elevated sea surface temperature. Here we evaluate early Paleocene CO2 by applying a leaf gas‐exchange model to Platanites leaves of four early Paleocene localities from the San Juan Basin, New Mexico (65.66–64.59 Ma). We first calibrate the model on two modern Platanus species, Platanus occidentalis and P. × acerifolia, where we find the leaf gas‐exchange model accurately predicts present‐day CO2, with a mean error rate between 5% and 14%. Applying the model to the early Paleocene, we find CO2 varies between ∼660 and 1,140 ppm. These estimates are consistent with more recent CO2 estimates from boron, leaf gas‐exchange, liverwort, and paleosol proxies that all suggest moderate to elevated levels of CO2 during the Late Cretaceous and early Paleocene. These levels of atmospheric CO2 are more in keeping with the elevated temperature during this period.

A PILOT STUDY OF SENSITIZATION TO PLANE TREE POLLEN IN SOFIA, BULGARIA

Purpose: Platanus pollen is a serious cause of asthma, allergic rhinitis and conjunctivitis in many European countries. The aim of the present pilot study is to investigate the sensitization to 3 different plane tree species in a group of patients with pollinosis. Materials and methods: 21 patients were surveyed - 11 men and 10 women. A skin prick test was performed with a set of allergens: Grass pollen mix; Betulaceae pollen mix; Platanusorientalis; Platanusacerifolia; Platanusoccidentalis. Results: 95% of patients are sensitized to grass pollen, with moderate positive skin reactions predominating. 86% have a co-sensitization to tree pollens also, particularly to the birch tree family. Only 3 (14%) of the studied patients showed slight positive skin tests to the studied plane tree allergens, with no significant difference in sensitization to studied Platanus species (p>0,05). Conclusion: At present, the sensitization to different Platanus species is not comparable to that of grass or birch pollen. However, it will be necessary to conduct new long-term, large-scale studies to prove whether Platanus pose a real threat to people in urban areas. The results of this interdisciplinary study are important both for clinical allergologists and for landscape architects and ecologists involved in the planning and management of urban green infrastructure.

Morphology and Systematic Affinities of Platanus dissecta Lesquereux (Platanaceae) from the Miocene of Western North America

Premise of research. Platanus leaves are common and readily recognized in Miocene floras across western North America, but different philosophies have been used to distinguish species from these fossil occurrences, and their relationships to modern Platanus have remained uncertain.Methodology. Fossils were studied under reflected light, transmission and epifluorescence microscopy, and microcomputed tomography (μ-CT). Morphological characters used to distinguish extant species of Platanus were applied to collections of Miocene Platanus from California, Oregon, Washington, and Idaho.Pivotal results. We provide an emended diagnosis for P. dissecta Lesquereux with new characters from stipule morphology and epidermal anatomy, and we review the distribution of this species among many localities in the Miocene of western North America. We designate a lectotype for P. dissecta and place P. bendirei (Lesquereux) Wolfe and other subsequently established names in synonymy. Fossil inflorescences, infructescences, and dispersed achenes found associated with P. dissecta are described as P. emryi sp. n.Conclusions. We determine that P. dissecta conforms to Platanus subg. Platanus in its enlarged petiole bases and lobed laminae but differs from modern Platanus species in that its associated capitula are borne on thicker axes, which we infer to have been longer than those of extant species. We find that P. dissecta bears close similarity to P. orientalis, P. racemosa, and P. gentryi and infer that it may have belonged to the Pacific North American/European clade within Platanus subg. Platanus that contains these three extant species and is readily distinguished from the eastern North American/Central American clade containing P. occidentalis and P. mexicana.

Transcriptome sequencing, molecular markers, and transcription factor discovery of Platanus acerifolia in the presence of Corythucha ciliata

The London Planetree (Platanus acerifolia) are present throughout the world. The tree is considered a greening plant and is commonly planted in streets, parks, and courtyards. The Sycamore lace bug (Corythucha ciliata) is a serious pest of this tree. To determine the molecular mechanism behind the interaction between the London Planetree and the Sycamore lace bug, we generated a comprehensive RNA-seq dataset (630,835,762 clean reads) for P. acerifolia by sequencing both infected and non-infected leaves of C. ciliata using the Illumina Hiseq 4000 system. We assembled the transcriptomes using the Trinity De Novo assembly followed by annotation. In total, 121,136 unigenes were obtained, and 80,559 unigenes were successfully annotated. From the 121,136 unigenes, we identified 3,010,256 SNPs, 39,097 microsatellites locus, and 1,916 transcription factors. The transcriptomic dataset we present are the first reports of transcriptome information in Platanus species and will be incredibly useful in future studies with P. acerifolia and other Platanus species, especially in the areas of genomics, molecular biology, physiology, and population genetics.

Changes in Gene Expression and Metabolite Profiles in Platanus acerifolia Leaves in Response to Feeding Damage Caused by Corythucha ciliata.

The sycamore lace bug, Corythucha ciliata (Say) is a highly invasive pest insect that feeds on sycamore trees (Platanus spp.) worldwide. The interaction between Platanus species and this insect pest has not yet been studied at the molecular level. Therefore, a recent study was conducted to compare the gene expression and metabolite profiles of Platanus acerifolia leaves in response to C. ciliata feeding damage after 24 and 48 h. We employed high throughput RNA sequencing (RNA- seq) to identify a total of 2,828 significantly differentially expressed genes (DEGs) after C. ciliata feeding. In addition, 303 unigenes were found to be up-regulated at both time points. Moreover, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that monoterpenoid biosynthesis, the linoleic acid metabolism pathway, and alpha- linolenic acid metabolism were the most prominent pathways among the DEGs. Further analysis of the metabolite profiles showed that nine metabolites were significantly different before and after C. ciliata damage. In addition, we analyzed DEGs detected in the P. acerifolia and C. ciliata interaction using Mapman. The terpene synthase gene family was also identified. We suggest that the results obtained from DEGs and metabolite analysis can provide important information for the identification of genes involved in the P. acerifolia–C. ciliata interaction, which might be necessary for controlling C. ciliata efficiently.

Increasing Incidence of Pediatric Eosinophilic Esophagitis in the Southwest of Madrid, Spain.

The incidence of eosinophilic esophagitis is unknown in our area. The aim of our study was to determine the incidence of eosinophilic esophagitis and its possible association with the most frequent absolute annual pollen counts. A descriptive retrospective multicenter observational study was designed to calculate the incidence of eosinophilic esophagitis in children aged under 15 years in the southwest region of Madrid, Spain in 2002-2013 (data were provided by the Statistics Institute of Madrid). We collected data on age, sex, clinical presentation, and date of endoscopic diagnosis. Relative risk (RR) was estimated (Stata v.11) using negative binomial regression models to assess the association between incidence and pollen counts (provided by Subiza Clinic). The study population comprised 254 patients (192 male [75.6%], aged 0.5-14.99 years). The clinical presentation was esophageal impaction in 23.6%, dysphagia in 22%, gastroesophageal reflux-like symptoms in 44.9%, and other findings in 9.4%. The annual incidence from 2002 to 2013 per 100 000 children aged <15 years per year was, respectively, 0.81, 1.5, 0.37, 3.17, 3.07, 4.36, 6.87, 7.19, 8.38, 9.05, 9.14, and 9.68. The incidence of eosinophilic esophagitis increased by an average of 19% annually (RR, 1.19; 95%CI, 1.14-1.25; P<.001). In the overall analysis, the relationship between incidence and absolute annual and monthly counts during the pollen seasons of the respective pollen types was analyzed only for Platanus species, which had an RR >1 (1.17 and 1.06, respectively) (P<.05). The incidence of diagnosis of pediatric eosinophilic esophagitis increased by an average of 19% annually. No significant association was found between incidence and pollen counts, except for a weak association with Platanus species.

A new species of Platanus from the Cenomanian (Upper Cretaceous) in eastern Heilongjiang, China

The stratigraphic division and sequence of the Upper Cretaceous sediments in eastern Heilongjiang Province, China, have been ambiguous and controversial, mainly due to a lack of biostratigraphically useful fossils and related radiometric dating. A new species of angiospermous fossil plant, Platanus heilongjiangensis sp. nov., from Qitaihe in eastern Heilongjiang has been found in sediments conformably above which zircons from a rhyolitic tuff has been dated by U–Pb radiometric methods as 96.2 ± 1.7 Ma, indicating that the Upper Houshigou Formation is of Cenomanian age. This discovery not only provides new data to improve our stratigraphic understanding of the Houshigou Formation, but also shows that Platanus flourished in the early Late Cretaceous floras of the region. This new study also indicates active volcanism taking place in the eastern Heilongjiang region during the Cenomanian of the Late Cretaceous.

First records of the sycamore lace bug, Corythucha ciliata (Say), in Greece

In late August 1988, the author noticed the presence of Corythucha ciliata (Say) (Hemiptera: Tingidae) in many plane trees of the following locations of northwestern Greece: 1) City of Kastoria, on 22.VIII.1988, along the coastal road of the city’s peninsula in Lake Orestias. Along this road, trees near the Panaghia Mavriotissa church were heavily infested, while trees further away were less so. Infested trees were also noticed along the quay of the northern end of the city. 2) Zagori, Epirus, on 24. VIII.1988, on the banks of the river Voidomatis, where the river meets the road between the villages Aristi and Papingo. The degree of infestation varied between adjacent trees. 3) Zagori, Epirus, on 25.VIII.1988, the single plane tree in the middle of the square of the village Eptahori. 4) City of Yannina, on 26. VIII. 1988, several single trees in the Kastro section of the city and also trees along the banks of the lake bordering the city. As heavily infested were recorded trees having most of their leaves chlorotic in the largest part of their laminae. On the underside of leaves that could be reached from the ground live adults, exuviae of immature stages and dark sports typical of excrement and of oviposition sites of Tingidae were found. On certain leaves more than 10 live adults per leaf were counted in Kastoria and Yannina. The identity of the species was determined by the author on adult specimens from Kastoria preserved dry and in ethanol. The fact that the infested locations were tens of kilometers apart and at considerably differ ent altitudes, leads to the conclusion that C. ciliata must have crossed the Greek northwest­ern border not less than two years ago. It is suspected that the insect entered Greece by natural spread from neighboring Albania. Examination by the author of plane trees in towns and villages of the Pella and Kilkis prefectures near the Yugoslavian border, showed no infestation. C. ciliata is of nearctic origin. In the northeastern and northwestern United States it is a pest of sycamore, Platanus occidentalis L., which is its preferred host plant, but also feeds on ash, hickory and also on mulberry. In Europe the host plants of preference are Platanus X acerifolia (Afton) Willd. and P. orientalis L., while such other broad-leaved trees as Brussonetia pap•rifera and ash are also reported as able to support the insect. The insect entered Europe and was noted first in Italy in 1964. Its spread was rather rapid, so that by 1986 it had spread to all the regions of Italy. In 1976 chemical control tests against it were re­ported from Hungary. Its presence in Yugoslavia was reported in 1972, in France in 1977, in Spain in 1981, in Switzerland in 1983 and in Austria in 1984. It is considered one of the three most important insects infesting the leaves of plane trees in Italy and generally very destructive. The adult insect is approximately 3 to 3.5 mm long and has reticulate front wings and reticulate expansions of the pronotum. The pronotum is yellowish, largely expanded on the sides which are transparent, and has a median vesicated process. The front wings are subquadrangular and have a proximal vesica which is globular and more or less smoky to­wards its internal margin. Two to three generations per year have been reported in Italy, same as in the northeastern United States. Hibernation takes place in the adult stage, mostly under loose bark at the basal part of the trunk or in other protected places nearby. In spring, the adults move to the young leaves, where they lay their eggs on the under side of the blade where the immature stages feed and develop and the long-lived adults re­main feeding and reproducing. The feeding punctures cause chlorosis which starts from the basal part of the leaf and may expand to almost the whole leaf. On the underside of leaves, where the insect lives in colonies, there are usually numerous small dark spots. Heavily infested species of Platanus, in addition to extensive yellowing, may undergo premature leaf drop. In Italy and especially in urban areas, C. ciliata continues to cause concern because of the weakening of plane trees which predis­poses them to attacks by other enemies. There is no doubt that the spread of C. ciliates in Greece will also be fairly rapid. The authorities should take advantage of the extensive work done in Italy, to further develop effective and ecologically sound control measures. Determining the resistance to the insect of Plalanus stock available in Greece should be among the projects to be encouraged.

Sycamore Tree Lace Bug (Corythucha ciliataSay) (Hemiptera: Tingidae) Reaches Africa

In February 2014 colonies of a large and conspicuous lacebug (Fig. 1A) were collected from the undersides of the leaves of London plane trees (Platanus x acerifolia) in the suburb of Newlands, Cape Town, South Africa. Infected leaves could easily be identified by their characteristic bronzed appearance (Fig. 1B). The lace bugs were subsequently identified as Corythucha ciliata (Say) using keys to North American Corythucha species (Mead 1989) and economically important tingids of the world (Stonedahl et al. 1992). Corythucha species have high host-specificity, whilst C. ciliata is the only lace bug known to feed on Platanus species (sycamores) - this association is thus considered to be diagnostic for the species (CABI 2014). C. ciliata has a broad native range across the eastern parts of North America and Canada, where it is largely monophagous on Platanus (sycamore) trees, with P. occidentalis being its main host. However, it also occurs on Platanus hybrids, and in invasive parts of its range feeds on P. orientalis and P. x acerifolia (the hybrid between P. occidentalis and P. orientalis (CABI 1984).

Characterization of protein expression of Platanus pollen following exposure to gaseous pollutants and vehicle exhaust particles.

Being major ornamental street trees, species of Platanus are widely planted in the Shanghai urban area. A great deal of allergenic Platanus pollen is released from the trees and suspended in the atmosphere during its flowering season, ultimately causing allergic respiratory diseases. Few papers have focused on the distribution of this type of pollen and its expression of allergenic proteins. In order to investigate any differences in protein expression in Platanus pollen following exposure to gaseous and particulate pollutants, a special apparatus was designed. Exposure condition (such as temperature, humidity, and exposure time) of Platanus pollen and gaseous pollutants can be simulated using of this apparatus. Fresh Platanus orientalis pollen, pollutant gases (NO2, SO2, NH3), and typical urban ambient particles (vehicle exhaust particles, VEPs) were mixed in this device to examine possible changes that might occur in ambient airborne urban pollen following exposure to such pollutants. Our results showed that the fresh P. orientalis pollen became swollen, and new kinds of particles could be found on the surface of the pollen grains after exposure to the pollutants. The results of SDS-PAGE showed that five protein bands with molecular weights of 17–19, 34, 61, 82, and 144 kDa, respectively, were detected and gray scale of these brands increased after the pollen exposure to gaseous pollutants. The two-dimensional gel electrophoresis analysis demonstrated that a Platanus pollen allergenic protein (Pla a1, with a molecular weight of 18 kDa) increased in abundance following exposure to pollutant gases and VEPs, implying that air pollutants may exacerbate the allergenicity of pollen.

Plastid DNA sequencing and nuclear SNP genotyping help resolve the puzzle of central American Platanus.

Recent research on the history of Platanus reveals that hybridization phenomena occurred in the central American species. This study has two goals: to help resolve the evolutive puzzle of central American Platanus, and to test the potential of real-time polymerase chain reaction (PCR) for detecting ancient hybridization. Sequencing of a uniparental plastid DNA marker [psbA-trnH((GUG)) intergenic spacer] and qualitative and quantitative single nucleotide polymorphism (SNP) genotyping of biparental nuclear ribosomal DNA (nrDNA) markers [LEAFY intron 2 (LFY-i2) and internal transcribed spacer 2 (ITS2)] were used. Based on the SNP genotyping results, several Platanus accessions show the presence of hybridization/introgression, including some accessions of P. rzedowskii and of P. mexicana var. interior and one of P. mexicana var. mexicana from Oaxaca (= P. oaxacana). Based on haplotype analyses of the psbA-trnH spacer, five haplotypes were detected. The most common of these is present in taxa belonging to P. orientalis, P. racemosa sensu lato, some accessions of P. occidentalis sensu stricto (s.s.) from Texas, P. occidentalis var. palmeri, P. mexicana s.s. and P. rzedowskii. This is highly relevant to genetic relationships with the haplotypes present in P. occidentalis s.s. and P. mexicana var. interior. Hybridization and introgression events between lineages ancestral to modern central and eastern North American Platanus species occurred. Plastid haplotypes and qualitative and quantitative SNP genotyping provide information critical for understanding the complex history of Mexican Platanus. Compared with the usual molecular techniques of sub-cloning, sequencing and genotyping, real-time PCR assay is a quick and sensitive technique for analysing complex evolutionary patterns.

Late Miocene Palaeoclimate and Ecosystem Dynamics in Southwestern Bulgaria − A Study Based on Pollen Data from the Gotse-Delchev Basin

A profile 63 m thick in the Late Miocene in the Gotse-Dechev Basin (SW Bulgaria) was sampled for pollen analysis in the Kanina opencast mine. The exposed sequence comprises a basal unit with brown coal-clay cycles and clayey/siliciclastic cover layers partly representing a lacustrine facies. A total of 60 pollen samples were analysed, but quantitative data are confined to 30 polleniferous samples. The palynological analysis carried out provides data about the composition and structure of the fossil vegetation. The main vegetation type was a mixed mesophytic forest dominated by Carya, Fagus, Betula, Quercus, and Ulmus. Accessory elements included Magnolia, Corylopsis, Liquidambar, Eucommia, Zelkova, Ulmus, Pterocarya, Juglans, Engelhardia, Platycarya, Symplocos, Araliaceae, Vitaceae, Hedera, Cornus, and Ilex. Mid- and high-altitude vegetation elements Tsuga, Abies, Keteleeria, Cathaya, Picea, Cedrus are also present. Swamp vegetation with high proportion of Alnus, and minor percentages of Taxodiaceae, Cyrillaceae, Myrica, Planera, some Poaceae, Cyperaceae, and some ferns also existed. Species of Platanus, Alnus, Pterocarya, Salix, Staphylea, and Liquidambar played important roles in the riparian vegetation. The aquatic vegetation consists of Butomus, Potamogeton, Menyanthes, Sparganium, Typha and Cyperaceae. Herbaceous palaeocoenoses had a limited distribution. The climatic data reconstructed by the Coexistence Approach indicate mean annual temperatures of ca. 15.6-17.1°C. For mean annual precipitation intervals from 1096 to 1347 mm are most common. The narrowest coexistence intervals for the mean of the coldest month are 5 to 7.5°C. Summer temperatures were mainly between 24.7 and 26.4°C. The curve obtained for the means of summer temperatures illustrates some cyclic changes, partly also observed for other temperature parameters. The dynamics of the reconstructed data indicate that the climatic changes were probably cyclical. However, the presence of several unconformities in the sampled section does not allow an unambiguous interpretation of these data.

Breeding of fast growing forest tree species for biomass production in Greece

Abstract The purpose of this review is to provide a critical analysis of the literature regarding the breeding of fast growing forest tree species dedicated to biomass production in Greece and to identify future goals. The main genera employed in pertinent research which show the most promising results for operational plantations belong to Populus spp. and Platanus spp. The best poplar clone ( P. x euramericana I-455) produced 16.54 t ha −1 y −1 dry weight averaged over different experimental plantations and rotation periods, while the best clone derived from the Greek breeding program ( Populus deltoides var. missouriensis × Populus nigra var . pubescens He-X/3) produced 14.23 t ha −1 y −1 respectively. The best results of Platanus species and hybrids were at the vicinity of 10 t ha −1 y −1 . Clones selected under a combination of higher temperature and drier condition regimes reflecting the Mediterranean field conditions will be valuable in future breeding under a changing climate and increased energy needs. The high genetic diversity of the virtually unattached local genetic reserve can provide even from the initial breeding cycles great opportunities for genetic improvement and significant genetic gains.

ITS Evolution in Platanus (Platanaceae): Homoeologues, Pseudogenes and Ancient Hybridization

Platanaceae is an old family of angiosperms extending back to the Early Cretaceous but consisting of a single extant genus, Platanus. Species of Platanus have long been known to hybridize, and the London plane, Platanus x hispanica, is a well-known example of a hybrid species that formed in historical times. In addition, morphological studies have suggested past interspecific or interlineage hybridization and reticulation as possibly important factors in the evolution of the genus. This study aims at unravelling the complex evolutionary information contained in internal transcribed spacer (ITS) sequences. The ITS of the 35S nuclear ribosomal DNA are biparentally inherited, multi-copy markers with a high potential for resolving intrageneric relationships especially when ancient hybridization (reticulation) is involved. Phylogenetic trees, splits graphs and motif analysis are used to extract phylogenetic information from 223 cloned ITS sequences, representing ten species and varieties of Platanus. Non-pseudogenous and pseudogenous sequence motives are assessed to explain how different evolutionary modes contribute to possibly conflicting character state patterns in the ITS. It was found that putative non-functional ITS copies ('pseudogenes') form distinct groups in phylograms and splits graphs, and that pseudogenous lineages reflect ancient hybridization events conserved in the ITS. Specifically, pseudogenous clones of an 'Atlantic' North American clade share sequence motives with non-pseudogenous clones of the western ('Pacific') North American P. racemosa species aggregate. In addition, evidence was found for recent lateral gene flow as a possible factor in the evolution of the central Mexican P. rzedowskii. Broad ITS data sets that cover intra- and interindividual variability reveal past and ongoing speciation processes in Platanus. Evolutionary pathways can be visualized with splits graphs, but not with bifurcating trees.

Metacercárias de Ascocotyle (Phagicola) longa Ransom, 1920 (Digenea: Heterophyidae), em Mugil platanus, no estuário de Cananéia, SP, Brasil

Estudou-se no estuário de Cananéia, litoral do estado de São Paulo, Brasil, a presença de Ascocotyle (Phagicola) longa Ransom, 1920 (Digenea: Heterophylidae), trematódeo, em tainha (Mugil platanus, Günther, 1880). Foram realizadas amostragens a fresco e cortes histológicos em tecidos provenientes de 61 exemplares. A presença de metacercárias foi comprovada em 100% dos peixes examinados, com a seguinte distribuição: coração (21,6%), fígado (19,7%) e rins (58,6%). As alterações histológicas no tecido cardíaco foram caracterizadas pela presença de um granuloma parasitário formado por uma cápsula de tecido conjuntivo ao redor do parasita, levando a um edema generalizado. Para determinar a infecção em alevinos de tainha da espécie M. platanus, foram capturados 100 exemplares nas entradas de córregos da região estuarino-lagunar. Esses peixes foram eviscerados para a pesquisa de metacercárias pelo exame a fresco, verificando-se que 100% dos alevinos não estavam infectados.

Phylogeny and Historical Biogeography of the Genus &lt;I&gt;Platanus&lt;/I&gt; as Inferred From Nuclear and Chloroplast DNA

Abstract Phylogenetic analyses of DNA sequences of six species of Platanus were conducted to estimate species relationships and analyze biogeographic history. On the basis of a broader analysis of the third exon of the nuclear gene LEAFY, the root node for the genus was confirmed to fall between subg. Castaneophyllum (P. kerrii) and the species of subg. Platanus. Separate phylogenetic analyses of the nuclear ribosomal ITS region, the 3′ region of the second intron of LEAFY, and the chloroplast region trnT-trnL intergenic spacer provided various levels of resolution, and the combined data yielded a fully resolved set of relationships within subg. Platanus. Two major clades were identified: one with species from Europe (EUR) and western North America (WNA) (P. orientalis, P. racemosa s.l.), the other with species from eastern North America (ENA; US and Canada) and eastern Mexico (EMEX) (P. mexicana, P. occidentalis, and P. rzedowskii). Within subg. Platanus, six subclades corresponded to previously recogniz...

Leaf Cuticular Morphology Links Platanaceae and Proteaceae

The leaf cuticular morphology of extant species of Platanus was investigated using light and scanning electron microscopy. All species are shown to possess trichome bases of the same type as those commonly found in Proteaceae. Of particular significance are compound forms that consist of an annular surface scar associated with more than one underlying epidermal cell. These are found on the adaxial leaf surfaces of all species of Platanus and are also clearly evident on the abaxial surface of Platanus orientalis. This type of trichome base is therefore interpreted as the first detected nonreproductive morphological synapomorphy linking Proteaceae and Platanaceae. Also, the laterocytic, sometimes paracytic, or anomocytic arrangement of subsidiary cells in Platanus is distinct from the general state in Proteaceae, which is brachyparacytic and presumably derived. In Bellendena, possibly the most basal genus of extant Proteaceae, subsidiary cell arrangements resemble those of Platanus. These results are discussed with respect to leaf fossil records of Proteales, where it is concluded that the combination of brachyparacytic stomata and compound trichome bases is strong evidence for Proteaceae.