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36 results on '"Hellwig, Frank H."'

7. Index

Author

Hellwig, Frank H and BioStor

Published
1990

11. Editorial

Author

Hellwig, Frank H.

Published
1999

19. Investigations on rhizome-morphology and growth strategies of geophytes of the Göttingen Forest

Author

Meyer, Karsten and Hellwig, Frank H.

Subjects
ddc:580
Abstract

Das Rhizomwachstum von sieben Pflanzenarten des Göttinger Waldes wurde untersucht. Dabei wurden Wachstumszeiten, Wuchsformen und phänologische Entwicklung festgestellt. Aus den Daten wurde auf die Wachstumsstrategien der Arten geschlossen und die oberirdische Entwicklung mit dem Rhizomwachstum verglichen. Es konnte festgestellt werden, daß das Rhizomwachstum kurz nach Beginn der Blattentfaltung einsetzt. Ab diesem Zeitpunkt liefert die Photosynthese der Blätter genügend Kohlenhydrate zum Aufbau neuer Rhizomabschnitte. Bei den sieben untersuchten Arten konnten drei verschiedene Wachstumsstrategien festgestellt werden. Früh blühende Arten folgen der Dominanzstrategie, um Licht monopolisieren zu können. Arten fleckenhafter Habitate folgen der Explorationsstrategie, die flexibel auf veränderte Umweltbedingungen reagieren kann. Spät blühende Arten folgen der unspezialisierten pragmatischen Strategie. The rhizome growth of seven plant species of the Göttingen Forest was investigated. The growth period, growth form and phenological development were determined. From that data-base, the growth strategies of the species were evaluated and the above-ground development was compared with the rhizome growth. It was found that the rhizome growth began during the first stages of leaf expansion. From this point photosynthesis produces sufficient carbohydrates for the construction of new rhizome segments. Three different growth strategies could be determined fot the seven species investigated. Early-flowering species follow a dominance strategy to monopolize light. Species of patchy habitats follow an explorative strategy which could react flexibly to changing environmental conditions. Late flowering species follow an unspecialized, pragmatic strategy.

Published
2017

20. Untersuchungen zur Rhizommorphologie und Wachstumsstrategie von Geophyten des Göttinger Waldes

Author

Meyer, Karsten, Hellwig, Frank H., Meyer, Karsten, and Hellwig, Frank H.

Abstract

Das Rhizomwachstum von sieben Pflanzenarten des Göttinger Waldes wurde untersucht. Dabei wurden Wachstumszeiten, Wuchsformen und phänologische Entwicklung festgestellt. Aus den Daten wurde auf die Wachstumsstrategien der Arten geschlossen und die oberirdische Entwicklung mit dem Rhizomwachstum verglichen. Es konnte festgestellt werden, daß das Rhizomwachstum kurz nach Beginn der Blattentfaltung einsetzt. Ab diesem Zeitpunkt liefert die Photosynthese der Blätter genügend Kohlenhydrate zum Aufbau neuer Rhizomabschnitte. Bei den sieben untersuchten Arten konnten drei verschiedene Wachstumsstrategien festgestellt werden. Früh blühende Arten folgen der Dominanzstrategie, um Licht monopolisieren zu können. Arten fleckenhafter Habitate folgen der Explorationsstrategie, die flexibel auf veränderte Umweltbedingungen reagieren kann. Spät blühende Arten folgen der unspezialisierten pragmatischen Strategie., The rhizome growth of seven plant species of the Göttingen Forest was investigated. The growth period, growth form and phenological development were determined. From that data-base, the growth strategies of the species were evaluated and the above-ground development was compared with the rhizome growth. It was found that the rhizome growth began during the first stages of leaf expansion. From this point photosynthesis produces sufficient carbohydrates for the construction of new rhizome segments. Three different growth strategies could be determined fot the seven species investigated. Early-flowering species follow a dominance strategy to monopolize light. Species of patchy habitats follow an explorative strategy which could react flexibly to changing environmental conditions. Late flowering species follow an unspecialized, pragmatic strategy.

Published
2017

21. Ausprägung wichtiger Eigenschaften für die generative Vermehrung einer gartenbaulichen Modell-Kultur unter dem Einfluss von Genotyp und Umwelt

Author

George, Eckhard, Hellwig, Frank H., Engels, Christof, Ghanem, Ghofran, George, Eckhard, Hellwig, Frank H., Engels, Christof, and Ghanem, Ghofran

Abstract

Die vorliegende Arbeit prüft bei der gärtnerischen Modell-Kultur Cyclamen den Einfluss des Genotyps (interspezifische Hybriden) auf generative Merkmale sowie bei C. persicum `Melody´ den Einfluss von Kultivierungsmaßnahmen wie die Besiedelung der Wurzeln durch einen symbiontischen Pilz (Piriformospora indica) in Kombination mit einem differenzierten Phosphor-Angebot auf vegetative und generative Merkmale: (1) Pflanzendurchmesser, (2) Blühzeitpunkt und Blütenanzahl, (3) Anzahl Samenanlagen pro Fruchtknoten, (4) Vitalität von Pollen und Samenanlagen, (5) Mikrosporogenese, (6) Befruchtungsvorgang (Pollenschlauchwachstum, Anteil Fruchtknoten mit Pollenschläuchen, Anzahl Pollenschläuche im Griffel und Penetration der Pollenschläuche in die Micropyle), (7) abortierte Blüten nach der Bestäubung (8) Samenbildung und (9) Samenanzahl., The present paper investigates Cyclamen as an horticultural model-culture. A main Focus is on the characteristics of the Cyclamen genotype, notably with interspecific hybrids. Further, Cyclamen persicum cv. served as a model to analyse effects on parameters of pollination, seed development and number of ovules per ovary, which are caused by a root colonization of the seed bearer with the symbiotic fungus Piriformospora indica (Piri) in combination with a differentiated phosphorus supply. In this regard, plant diameter, flowering time and flower number, the viability of pollen and ovules, the microsporogenesis, the growth of pollen tubes, the seed formation and the seed count were considered among important parameters of pollination and seed development.

Published
2011

32. A new test of phylogenetic model fitness addresses the issue of the basal angiosperm phylogeny

Author

Goremykin, Vadim V. and Hellwig, Frank H.

Subjects
*PHYLOGENY, *ANGIOSPERMS, *GENOMES, *DNA
Abstract

Abstract: We readdress the issue of phylogeny of the basal extant angiosperms employing a source previously not systematically investigated, specifically, the non-coding sequences of cpDNA. Comparison of trees with and without grasses or the outgroup (Pinus) in our analyses revealed no rearrangements in tree topology that might be expected if LBA were distorting the position of the magnoliids. For each model applied, irrespective of whether monocots or ANITA members appeared basally divergent, the orchid Phalaenopsis assumed the same position on the trees with the reduced taxon set as did the branch bearing the orchid plus the grasses in the full alignment. However, our new test of model fitness revealed a different flaw influencing the placement of monocots, which is related to model mis-specification. This flaw similarly affects the full alignment and the alignment with grasses removed. In both cases the models favouring a relatively derived position for the monocots and basal placement of the branch of Amborella plus Nymphaea provide better overall prediction of the observed data structure. In the view of apparent unsuitability of the bootstrap method for large data sets, our novel test provides a new means of exploring conflicts caused by systematic errors in phylogenetic analyses. [Copyright &y& Elsevier]

Published
2006
Full Text
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33. The systematic position of Pachyglossaand Clasmatocolea(Jungermanniopsida: Lophocoleaceae) inferred from nrDNA ITS sequences and morphology

Author

Hentschel, Jörn, Feldberg, Kathrin, Zündorf, Hans-Joachim, Hellwig, Frank H., Schneider, Harald, and Heinrichs, Jochen

Abstract

Maximum parsimony (MP) and maximum likelihood (ML) analyses of 67 nrITS sequences of various genera of the liverwort families Lophocoleaceae and Plagiochilaceae as well as Herbertaceae (outgroup) lead to a fully resolved phylogeny with the separation of Lophocoleaceae and Plagiochilaceae having a bootstrap support of 93 to 99. The monospecific genus Leptophyllopsisis placed sister to the remainder of Lophocoleaceae. Heteroscyphusis found to be monophyletic (ML) or paraphyletic (MP) with Chiloscyphus polychaetusnested in a robust subclade of Heteroscyphus. Leptoscyphusis nested in Chiloscyphusand placed sister to a clade including Chiloscyphussubgenera Chiloscyphus, Lophocoleaand Notholophocolea(Chiloscyphusclade I). Chiloscyphussubg. Connatiis placed sister to this Leptoscyphus/Chiloscyphusclade. Several accessions of Chiloscyphus, which have also been treated as genus Clasmatocoleaare nested in Chiloscyphusclade I. The generitype of Pachyglossais part of Chiloscyphusclade I and placed sister to Chiloscyphussubg. Notholophocolea. Pachyglossadiffers only by its multistratose leaves from Chiloscyphussubg. Notholophocolea. Based on morphological similarities and the outcome of the molecular investigation, Pachyglossais transferred to Chiloscyphusand Chiloscyphus polychaetusto Heteroscyphus. Five new combinations are introduced.

Published
2007
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34. Systematic position of the genera Serratulaand Klaseawithin Centaureinae (Cardueae, Asteraceae) inferred from ETS and ITS sequence data and new combinations in Klasea

Author

Martins, Ludwig and Hellwig, Frank H.

Abstract

The systematic positions of the genera Serratulaand Klaseawere investigated on the basis of nuclear ribosomal DNA internal and external transcribed spacer sequences. Klaseacomprises the major part of the species traditionally placed in Serratula. Serratulais part of a clade containing the more derived genera of Centaureinae, whereas Klaseais a basal segregate within the subtribe, possibly sister to the Rhaponticumgroup. Nikitinia, a monotypic genus whose affinities were supposed by some authors in Carduinae, by others in Centaureinae, clearly belongs to Klaseaand is sunk into synonymy of the latter. A total of six new combinations are made in Klasea.

Published
2005
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36. Ausprägung wichtiger Eigenschaften für die generative Vermehrung einer gartenbaulichen Modell-Kultur unter dem Einfluss von Genotyp und Umwelt

Author

Ghanem, Ghofran, George, Eckhard, Hellwig, Frank H., and Engels, Christof

Subjects
39 Landwirtschaft, Garten, Cyclamen persicum, Piriformospora indica, Mikrosporogenese, ovules, Flowcytometrie, Interspecific Cyclamen Hybrids, 630 Landwirtschaft, Veterinärmedizin, ddc:630, Pollenschlauchwachstum, seed set, Samenanlagen, flow cytometry, viability, pollen tube growth, Pflanzenentwicklung, ZC 65200, phosphorus fertilization, seed formation, pollen, Vitalität, Phosphor-Düngung, Interspezifische Cyclamen-Hybriden, Samenbildung, microsporogenesis, plant development, ZC 52000, Samenertrag
Abstract

Die vorliegende Arbeit prüft bei der gärtnerischen Modell-Kultur Cyclamen den Einfluss des Genotyps (interspezifische Hybriden) auf generative Merkmale sowie bei C. persicum `Melody´ den Einfluss von Kultivierungsmaßnahmen wie die Besiedelung der Wurzeln durch einen symbiontischen Pilz (Piriformospora indica) in Kombination mit einem differenzierten Phosphor-Angebot auf vegetative und generative Merkmale: (1) Pflanzendurchmesser, (2) Blühzeitpunkt und Blütenanzahl, (3) Anzahl Samenanlagen pro Fruchtknoten, (4) Vitalität von Pollen und Samenanlagen, (5) Mikrosporogenese, (6) Befruchtungsvorgang (Pollenschlauchwachstum, Anteil Fruchtknoten mit Pollenschläuchen, Anzahl Pollenschläuche im Griffel und Penetration der Pollenschläuche in die Micropyle), (7) abortierte Blüten nach der Bestäubung (8) Samenbildung und (9) Samenanzahl. The present paper investigates Cyclamen as an horticultural model-culture. A main Focus is on the characteristics of the Cyclamen genotype, notably with interspecific hybrids. Further, Cyclamen persicum cv. served as a model to analyse effects on parameters of pollination, seed development and number of ovules per ovary, which are caused by a root colonization of the seed bearer with the symbiotic fungus Piriformospora indica (Piri) in combination with a differentiated phosphorus supply. In this regard, plant diameter, flowering time and flower number, the viability of pollen and ovules, the microsporogenesis, the growth of pollen tubes, the seed formation and the seed count were considered among important parameters of pollination and seed development.

Published
2011

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