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101.
Conclusion The greater tolerance of Dayton to A1 can be explained by a longer resistance of the plasmalemma towards A1 stress. Whether a stronger mucigel production could be resonsible for increased A1 tolerance has to be examined in more detail.  相似文献   
102.
Summary The critical theory of evolution was developed by a group of scientists working together with Wolfgang F. Gutmann at the Senckenberg-Research-Institute in Frankfurt am Main. Gutmann worked at Senckenberg for 37 years. In this time he presented 247 contributions which are distributed over 47 periodicals and books. The ideas that were developed by Gutmann and his colleagues were innovative and pathbreaking for morphology and evolutionary biology. The large number of his morphological publications is indicative of the wide field that was opened up by the concepts of constructional morphology. As some of his colleagues have suggested, constructional morphology as an engineering approach to the study of organisms (i. e., engineering morphology) may replace the traditional concepts of morphology and anatomy and provides the observational base for the historical reconstruction of evolutionary pathways. Constructional morphology as a quasi-engineering approach can be the morphological pendant to the contemporary molecular approaches to biology, as it can provide the necessary morphological basis for the interpretation of the results of molecular studies in the light of evolution.  相似文献   
103.
Intraspecific Variation in Cryptocaryon irritans   总被引:10,自引:0,他引:10  
ABSTRACT. Intraspecific variation in the ciliate Cryptocaryon irritans was examined using sequences of the first internal transcribed spacer region (ITS-1) of ribosomal DNA (rDNA) combined with developmental and morphological characters. Amplified rDNA sequences consisting of 151 bases of the flanking 18 S and 5.8 S regions, and the entire ITS-1 region (169 or 170 bases), were determined and compared for 16 isolates of C. irritans from Australia, Israela and the USA. There was one variable base between isolates in the 18 S region nd 11 variables indicate that Australian C. irritans isolates from estuarine (Moreton Bay) and coral reef (Heron Island) environments are distinct. The Heron Island isolate was genetically closer to morphologically dissimilar isolates from Israel (1.8% divergence) and USA (2.3 % divergence) than it was to the Moreton Bay isolates. Three isolates maintained in our laboratory since February 1994 originated from the same source. During this time the sequence of the isolates from wild fish in Moreton Bay remained unchanged. These genetic differences indicate the existence of a founder effects in laboratorty populations of C. irritans . The genetic variation found here, combined with known morphological and developmental differences, is used to characterise four strains of C. irritans .  相似文献   
104.
Phyllagathis tuberculata King and two closely allied new species,P. magnifica A. Weber andP. stonei A. Weber, are described and illustrated. Within the genus, these species form a distinct and isolated group which is restricted to Peninsular Malaysia.P. tuberculata occurs in Perak (probably confined to G. Bujang Melaka),P. magnifica andP. stonei are found in the mountains on the Pahang/Selangor border (Genting Highlands, Gombak valley). The distinctive characters of the three species are listed and some general information relating to inflorescence morphology, tubercle anatomy, fruit structure and seed dispersal is provided.  相似文献   
105.
Summary The Ca, Mg, S, Mn and Cu contents in leaves ofCoffea canephora trees selected in 64 plots under a 4×4×2 NPK trial were determined after seven years of fertilizer application. It was observed that NPK applications increased Mn uptake, P application increased the uptake of Cu, Ca and S while application of N and K did not enhance the uptake of Cu, Mg, Ca and S. It was shown that as a result of NPK applications, Ca and Mg had become deficient in coffee leaves, which corroborates earlier findings based on soil analysis.  相似文献   
106.
 Nuclear ribosomal (ITS) DNA sequence data from representatives of eleven out of 12 genera previously included in Thlaspi sensu lato were analyzed to elucidate relationships within the former genus Thlaspi sensu lato. Sequences from Thlaspi segregates Noccaea, Masmenia, Callothlaspi, Kotschyella, Microthlaspi, and Noccidium were added to the existing data sets, and only some Thlaspi sensu lato segregates formed a monophyletic group. The recently renamed genus Pseudosempervivum, formerly part of the genus Cochlearia, has been shown to be closely related to this group as well. Microthlaspi consists of three independent lineages of which Microthlaspi umbellatum is closely related to Neurotropis. The Thlaspi s.str. taxa including the type species T. arvense, are closely related to Peltaria and Alliaria and they represent a monophyletic group. Kotschyella and Noccidium, which were also integrated into Thlaspi s.l. are not closely related to any Thlaspi lineage. Therefore, we suggest major taxonomical changes which are not in agreement with concepts based on morphological data. Our ITS based phylogeny demonstrates that subtribe Thlaspidinae comprises some additional genera such as Teesdalia, Peltaria, and Alliaria, the latter two even previously classified in other tribes than tribe Lepidieae. Received August 15, 2000 Accepted January 30, 2001  相似文献   
107.
Abstract

The phylogeny of living and fossil snakes is assessed using likelihood and parsimony approaches and a dataset combining 263 morphological characters with mitochondrial (2693 bp) and nuclear (1092 bp) gene sequences. The ‘no common mechanism’ (NCMr) and ‘Markovian’ (Mkv) models were employed for the morphological partition in likelihood analyses; likelihood scores in the NCMr model were more closely correlated with parsimony tree lengths. Both models accorded relatively less weight to the molecular data than did parsimony, with the effect being milder in the NCMr model. Partitioned branch and likelihood support values indicate that the mtDNA and nuclear gene partitions agree more closely with each other than with morphology. Despite differences between data partitions in phylogenetic signal, analytic models, and relative weighting, the parsimony and likelihood analyses all retrieved the following widely accepted groups: scolecophidians, alethinophidians, cylindrophiines, macrostomatans (sensu lato) and caenophidians. Anilius alone emerged as the most basal alethinophidian; the combined analyses resulted in a novel and stable position of uropeltines and cylindrophiines as the second‐most basal clade of alethinophidians. The limbed marine pachyophiids, along with Dinilysia and Wonambi, were always basal to all living snakes. Other results stable in all combined analyses include: Xenopeltis and Loxocemus were sister taxa (fide morphology) but clustered with pythonines (fide molecules), and Ungaliophis clustered with a boine‐erycine clade (fide molecules). Tropidophis remains enigmatic; it emerges as a basal alethinophidian in the parsimony analyses (fide molecules) but a derived form in the likelihood analyses (fide morphology), largely due to the different relative weighting accorded to data partitions.  相似文献   
108.
 Isozyme markers and morphological characters were studied in four populations of Sphagnum capillifolium and S. quinquefarium. Recombinant plants were found in three populations, where the two species occur sympatrically. All recombinants possessed different haplotypes and combinations of morphological characters, which show that they are results of independent hybridization events. Strongly male-biased sex ratios were found for Sphagnum capillifolium in all populations where it grew sympatrically with S. quinquefarium. Most of the recombinants were also male fertile. These observations suggest that S. quinquefarium is the female parent in the primary crosses and in subsequent backcrosses. Received September 3, 2001; accepted March 16, 2002 Published online: November 7, 2002 Addresses of the authors: Nils Cronberg (e-mail: Nils.Cronberg@sysbot.lu.se), Department of Systematic Botany, Lund University, S?lvegatan 37, SE-223 62 Lund, Sweden. Rayna Natcheva (e-mail: renimoss@iph.bio.bas.bg), Institute of Botany, Bulgarian Academy of Sciences, 23 Acad. G. Bonchev Str., 1113 Sofia, Bulgaria.  相似文献   
109.
 Variation of 80 multistate morphological characters and isozymes encoded by 13 loci among 23 vetch species of the type subgenus of the genus Vicia in comparison with V. dumetorum, V. pisiformis and V. sylvatica of the subgenus Cracca is described and analyzed with cladistic parsimony and phenetic neighbour-joining methods by using two different ways of coding. Morphological analyses showed the subgenus Vicia monophyletic and revealed subgroups in a general agreement with traditionally recognized sections, except showing V. faba nested within section Narbonensis and ambiguity in the position of V. lathyroides and V. bithynica. Parsimony analysis of orthozymes as presence/absence characters revealed in the subgenus two basic monophyletic clades: 1) V. faba and three species of the section Peregrinae, V. michauxii, V. aintabensis and V. peregrina, in one subclade linked with species of the Narbonensis and Hyperchusa sections together with V. pisiformis of subgenus Cracca in a second subclade; 2) species belonging to sections Vicia, Sepium, Pseudolathyrus and Lathyroides together with V. sylvatica of the subgenus Cracca. Neighbour-joining analysis of orthozymes revealed the same two basic groups, differing only in the relative position of some species in subclusters. Both isozyme analyses showed paraphyly of the subgenera Vicia and Cracca. Parsimony analysis of orthozymes as character states of isozymes yielded a largely unresolved strict consensus cladogram of 209 most parsimonious trees, and reweighting of characters failed to produce a stable tree. Phylogenetic congruence and discordance among morphological and isozyme analyses, coding ways, homoplasy and weighting of characters are discussed. Received November 20, 2001 Accepted January 31, 2002  相似文献   
110.
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