Research themes


Teaching activities

PD Dr Wolfgang Schmidt 



Max-Planck Institute for 
Limnology (Plön), 
Department of Tropical 

Max-Planck Institute for 
Chemistry (Mainz), 
Department of 

University Bonn, 
Ecophysiology of 
Plants - Institute of Botany

Instituto National de 
Pesquisas da Amazônia 
(INPA) at Manaus (Brasil)

Bundesanstalt für 
Züchtungsforschung an 
Institut für 

Humboldt-Universität Berlin,
AG Angewandte Botanik


Research activities 

The central aim of our work is to search for the mechanistic basis of adaptive processes in terrestrial plants to adverse soil conditions and to understand the regulation of acclimatory processes in response to environmental changes. Research is focused on the regulation of iron homeostasis, stimulus-induced epidermal cell differentiation, and on adaptations of trees from the Central Amazon floodplain to flooding stress. 
Iron levels in plants are controlled by various parallel but, at least partly, separate pathways. The role of inter-organ signaling in coordinating the responses of root cells (expression and subcellular localization of membrane bound enzymes, and structur changes such as the formation of transfer cells, root hairs and cluster roots) to the plants`s demand is investigated by means of immunocytochemical labeling and in situ hybridization in hormone-related mutants and in mutants with de-regulated Fe uptake.
The role of putative signal transmitters in the induction of the various responses to Fe deficiency is also studied. A further point of interest is the identification of iron responsive elements (IREs) and iron responsive element binding proteins (IRPs). Root epidermal cells can differentiate into hair or non-hair cells, often in a well-defined, predictable pattern. This pattern is affected by various abiotic stimuli, such as sub-optimal supply of the essential nutrients iron and phosphate. We are investigating the signal pathways leading to alterations in epidermal patterning by screening mutants in Arabidopsis that are unable to induce the phenotypes characteristic of phosphate-deficient plants. The isolation of genes involved in the translation of environmental signals to changes in epidermal cell specification in the aging primary root should help to understand the molecular basis underlying the adaptation of plants to adverse soil conditions. 
Low oxygen levels in the rhizosphere, caused by waterlogging or complete submergence, is a serious environmental stress that affects plant productivity and distribution in natural habitats. The Central Amazon floodplain is one of the largest inundation areas in the world. Plants of the inundation forests are subjected to flooding periods for up to ten months with an average amplitude of about ten meters. The monomodal flood pulse causes an annual change between relatively dry and oxic conditions and prolonged flooding, causing drastic changes in the bioavailability of nutrients, oxygen levels, and concentration of phytotoxins. By using morphological, physiological, biochemical, and molecular approaches, we are trying to add insights in the adaptations that have evolved in flood-tolerant trees to overcome the long flooding periods. 


Selected puplications
Schikora A, Schmidt W. 2001. Iron stress-induced epidermal cell fate is regulated independently from physiological acclimations to low iron availability. Plant Physiology 125: 1679-1687
Schmidt W, Schikora A. 2001. Different pathways are involved in phosphate and iron stress-induced alterations of root epidermal cell development. Plant Physiology 125: 2078-2084
Pich A, Manteuffel R, Hillmer S, Scholz G, Schmidt W. 2001. Fe homeostasis in plant cells: Does nicotianamine play multiple roles in the regulation of cytoplasmic Fe concentration? Planta 213:967-976
Schikora A, Schmidt W. 2002. Formation of transfer cells and H+-ATPase expression in tomato roots under P and Fe deficiency. Planta 215: 304-311
Schmidt W, MichalkeW, Schikora A. 2003. Proton pumping by tomato roots. Effect of Fe deficiency and hormones on the activity and distribution of plasma membrane H+-ATPase in rhizodermal cells. Plant, Cell & Environment 26: 361-370
De Simone O, Haase K, Müller E, Junk W, Hartmann K, Schreiber L, Schmidt W. 2003. Apolasmic barriers and oxygen transport properties of hypodermal cell walls in roots from four Amazonian tree species. Plant Physiology 132: 206-217
Schmidt W. 2001. From faith to fate. Ethylene signaling in morphogenic responses to P and Fe deficiency. Journal of Soil Science and Plant Nutrition 164: 147-154
Schmidt W. 2003. Iron solutions: acquisition strategies and signaling pathways. Trends in Plant Science 8: 188-193