Karl H. Hasenstein
1976 B.S. (Biology) University of the Saarland, Germany
1977 M.S. (Biology) University of the Saarland, Germany
1982 Ph.D. (Plant Physiology) University of the Saarland, Germany
My research interests include gravitational biology, the effect of phytohormones, function of the plant cytoskeleton and plant environment interactions.
Gravitational Biology: Our ill-fated Space Shuttle Experiment on Board STS-107 was designed to test the gravisensing mechanism in plants. Despite the tragedy of this experiment we determined that the graviperception mechanism apparently depends on the extent of (mechano)stimulation. We study the perception step using High Gradient Magnetic Fields (HGMF) , which repel strong diamagnetic substances such as starch. The diamagnetic properties of starch permits intracellular displacement by HGMF. The resulting root curvature allows the analysis of the magnitude of displacement, force-equivalents and more.
My research also aims to decipher regulatory functions and pathways of phytohormones, especially auxin and abscisic acid. Hormone (auxin) transport is a likely pathway for intercellular communication and regulation in response to varius stimuli. Especially valuable in studying these internal communication systems are gravitropically induced plant movements, because they allow (at least in roots) an independent evaluation of receptor-transduction- and response-sites and/or pathways. Studies on gravitropism are useful for many aspects of growth regulation, especially the involvement and response of the cytoskeletal elements due to changes in external factors e.g. light, osmotic conditions, or mechanical manipulation. Using confocal microscopy we study the behavior of microtubules and actin filaments after exposing roots to specific treatments. Structural studies are supplemented by our capability to analyze the content of several phytohormones/ growth regulators using state-of-the-art gas-chromatography coupled with mass-spectroscopy (GC-MS).
Plant movements are not limited to growth movements such as gravi-curvature but include fast, typically turgor mediated, movements. I am interested in one such movement, namely the contraction of staminal filaments in thistles. This work involves the use of a pressure probe, analyzing carbohydrate composition, and anatomical features and is designed to understand the visco-elastic properties of plant tissue.
My research is funded through NASA, NSF and DOE.
Your interest in this type of research will certainly be stimulated when you look at some other web sites, for example:
Life Sciences Program at NASA and
Astrobiology or
American Society of Gravitational and Space Research
Mass Spectrometry on the Internet
Feel free to contact me at this address:
Karl H. Hasenstein, Department of Biology, PO Box 42451, Lafayette, LA 70504 or
hasenstein@louisiana.edu, Telephone: (337) 482-6750