Prof. Dr. H. Chr. Weber
Diploma Thesis:1974 Gießen
Doctoral Thesis: 1976 Gießen
Habilitation: 1982 Ulm
Professor of Botany: 1982 Marburg
- Other publications of group members
- Diploma Theses
- State examination Theses
- Members of the group
- Research report Dr. S. Imhof
Our group works on structural aspects of parasitic and mycotrophic vascular plants. Parasitic vascular plants are investigated with special regard to phylogenetic progressions as well as ecological and economical problems in agriculture and forestry caused by their mode of life. Aside of economical and ecological concern our research on mycotrophy also comprises systematic and phylogenetic aspects. Recently, a special interest is posed on the Flora of the Maltese Islands. We try to asses the floristic diversity, including evaluation, distribution, ecology, and structures of plant interactions.
Arbuscule, a characteristic feature of the vesicular-arbuscular mycorrhiza, in a root of Zea mays
Anatomical structure of a Pedicularis palustris haustorium (cross section) attacking a host root (longitudinal).
Some questions we address are:
- What different types of parasitic and mycotrophic mode of life can be distinguished and how can we line such types with respect to evolutionary progression, are there relevant features elucidating the systematic relations of plant groups?
- How can we improve cultivation, including pest management, using our knowledge
- How many and which plant species are found on the Maltese Islands?
Which are endemic? Where are vulnerable hot spots with highest priority
for nature conservation?
More information, including many descriptive
pictures, are available at our Website
Cliffs of Gozo with the National Plant of Malta Palaeocyanus crassifolius
Palaeocyanus crassifolius with a chameleon,
introduced in the Maltese Islands from Africa
Gworgwor, N. A. and H. Chr. Weber (2004): The effect of arbuscular mycorrhiza (AM) fungi on the control/management of Striga hermonthica in Sorghum. Proc. 8th Int. Parasitic Weeds Symp., Durban (SA), 2004, p. 35.
Wu, W. Y., H. Chr. Weber, and S. Imhof (2004): Morphogenesis and structure of hairs of Tetrapanax papyriferus (Hook.) K.Koch (Araliaceae). Beitr. Biol. Pflanzen, 73: 213-221.
Weber, H. Chr. (2004): Wild Plants of Malta. P.E.G. Ltd., Malta
Weber, H. Chr. (in press): Ornamental Plants of Malta. P.E.G. Ltd., Malta
Weber, H. Chr. and B. Kendzior (in press): Flora of the Maltese Islands - A Field Guide. Margraf Publishers GmbH, Weikersheim
Other publications of group members
Franke, T., L. Beenken, M. Döring, A. Kocyan and R. Agerer (2004): Mycorrhizal Specificity in the Myco-heterotrophic Genus Afrothismia (Burmanniaceae; tribe: Thismieae). 17th Annual Meeting 2004 "Biodiversity, and dynamics in tropical ecosystems" of the Society for Tropical Ecology, Bayreuth (Germany), February 18 - 20.
Döring, M., D. Ewald and P. Müller (2005): Intracellular occurrence of bacteria in root hairs of Eleutherococcus sieboldianus (Makino) Koidz. plantlets. Symposium on Mechanisms of cellular compartmentalization SFB 593, Marburg (Germany) April 6 - 8.
D. Ewald and M. Döring (2005): Investigations concerning the formation of somatic embryos in Eleutherococcus sieboldianus (Makino) Koidz. (Araliaceae). COST 843 and COST 851 Joint Meeting, Stara Lesna(Slovakia) June 28 - 3 July
F. Grolig, M. Döring, and P. Galland (2005). Gravisusception by buoyancy: a mechanism ubiquitous among fungi? Protoplasma (submitted)
Enke, Neela: "Morphologische und anatomische Untersuchungen an Conopholis americana (L.) Wallr. (Orobanchaceae)"
Pohris, Carina: "Strukturelle Untersuchungen der Mycorrhiza an Polygala-Arten”
Rath, Magnus: „Morphologisch - anatomische Untersuchung von Sabatia grandiflora (Gray) Small und Eustoma exaltatum (L.) Salisb. (Gentianaceae) unter besonderer Berücksichtigung ihrer Mycorrhiza“
State examination Theses
Palm, Holger: "Strukturelle Untersuchungen an den unterirdischen Organen von Oxalis pes-caprae (Oxalidaceae)"
Members of the group
Matthias Döring (PhD Student)
Katharina Dörr (Technician)
Dr. Stephan Imhof (Assistant)
Bernd Kendzior (Assistent)
Dr. Johanna Knappe (Guest Scientist)
Florian Lemmer (Diploma Student)
Holger Palm (State Examination Student)
Carina Pohris (Diploma Student)
Magnus Rath (Diploma Student)
Ulf Sewe (Diploma Student)
Prof. Dr. Hans Christian Weber (Group Leader)
Wu Wenying (PhD Student)
AG Spezielle Botanik
Research report Dr. S. Imhof
Dr. S. Imhof
Study of Biology in Marburg and St. Petersburg/Florida
Diploma Thesis:1994 Marburg
Doctoral Thesis: 2000 MarburgPostdoc since: 2002
Plants are green and autotrophic - usually. If this is not the case, because there is no evidence for saprophytic abilities in vascular plants, neither bryophytes or even in algae, these plants are either parasitic or myco-heterotrophic. Both nutritional strategies are fascinating deviations from the normal mode of life in plants whereas myco-heterotrophy is subject of my research.
Myco-heterotrophic plants (MHP) are achlorophyllous, hence non-photosynthetic, and are entirely depend on mycorrhizal fungi for their carbon supply. Despite this obvious abnormality, very little was known on the subterranean structures and mycorrhizal colonization in MHP, except for some temperate achlorophyllous orchids and Monotropaceae. Own research on Burmanniaceae, Gentianaceae and Triuridaceae have revealed complex mycorrhizal colonization patterns, considerably differing from mycorrhizas in autotrophic plants (see Fig. 1) Parts of the plant body are designed to harbour the essential fungus without harming it, but others quickly digest the hyphae. This compartmentation allows a sustained benefit from the fungus for the plant even with only a few external fungal penetrations. Especially because the perceptive surface of many MHP is low due to root/rhizome reductions (see Fig. 2), and, therefore, the probability for an appropriate fungal penetration is decreased, these adaptations are likely to be ecologically essential.
The structural diversity of mycorrhizas among MHP is tremendous: in ten different myco-heterotrophic species investigated nine distinct mycorrhizal pattern were found. Evolutionary progression lines with the trend towards increased efficiency of the mycorrhiza for the plant can be inferred from some Gentianaceae and Burmanniaceae, and this may be important to understand the evolution of mycorrhiza in general.
Fig. 1 Hyphal loops, a specific character for the mycorrhiza in the achlorophyllous Afrothismia sp. (Burmanniaceae) only occurring in the exodermis of its peculiarly enlarged root bases
Fig. 2 Young stage of Voyria tenella. (Gentianaceae). The shoot just emerges from the morning-star-like root system (arrow). The root system will not increase much, carbon and nutrients are provided by the endophytic fungus
More information at my Website:
Imhof, S. (2005): Two distinct fungi colonize roots and rhizomes of the myco-heterotrophic Afrothismia gesnerioides (Burmanniaceae). Can. J. Bot. (submitted).
Imhof, S. (2005): Fundmeldungen 1196.-1200. Botanik und Naturschutz in Hessen 18: 75-77
Imhof, S. (2005): Botanik-Quiz. Ein Beitrag zum Online-Projekt 'Naturdetektive' des Bundesamtes für Naturschutz. Http://www.naturdetektive.de (unter 'E-Learning').
Imhof, S. (2004): Fundmeldungen 1128.-1133, Buchbesprechung, Website-Empfehlungen. Botanik und Naturschutz in Hessen 17: 138-140, 173-174, 179-183
Imhof, S. (2004): Morphology and development of the subterranean organs of the achlorophyllous Sciaphila polygyna (Triuridaceae). Bot. J. Linn. Soc. 146: 295-301.
Wu, W. Y., H. Chr. Weber, and S. Imhof (2004): Morphogenesis and structure of hairs of Tetrapanax papyriferus (Hook.) K.Koch (Araliaceae). Beitr. Biol. Pflanzen 73: 213-221