title: Recent results of the joint ESA-DARA/IBMP experiments Biokosmos "Seeds".
abstract: Comparison of experimental data obtained from short (SDEF) and long duration exposure flights (LDEF) have recently led to results which will be significant for longer and/or repeated sojourn of man in space. Under orbital conditions biological stress and damage are induced in test subjects by cosmic radiation, especially the high energetic, densely ionizing component of heavy ions. Plant seeds were successful model systems for a biotest in studying the physiological damages and mutagenic effect caused by ionizing cosmic radiation in particular stem cells. Dosimetrically, the subdivision into charge- and Let-groups reveals the contribution of the intermediate group (LET = 350-1000 MeV/cm) due to the medium heavy ions (Z = 6-10). Their relative contribution increases with the lower inclination of the orbit of LDEF-1; on the other hand, the total fluence becomes higher with longer duration of the flight. The observed endpoints of the biological radiation damage hint at a correlation with particle dose rate rather than with the dose; additionally, data on shielding effects inside and outside the space craft and its exposure were gained from the different SDEF- and LDEF-missions.
authors.affiliation: Botanical Institute, J.W. Goethe University, Frankfurt am Main, Germany.
authors.forename: A R
authors.initials: AR
authors.lastname: Kranz
authors.forename: K E
authors.initials: KE
authors.lastname: Gartenbach
authors.forename: V V
authors.initials: VV
authors.lastname: Shevchenko
authors.forename: E
authors.initials: E
authors.lastname: Schopper
authors.forename: B
authors.initials: B
authors.lastname: Baican
authors.forename: J U
authors.initials: JU
authors.lastname: Schott
authors.forename: R
authors.initials: R
authors.lastname: Seltz
authors.forename: C
authors.initials: C
authors.lastname: Heilmann
authors.forename: D
authors.initials: D
authors.lastname: Dudkin
authors.forename: N
authors.initials: N
authors.lastname: Nefedov
authors.forename: Y
authors.initials: Y
authors.lastname: Potapov
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000528:radiation effects*; D003359:Cosmic Radiation; D004307:Dose-Response Relationship, Radiation; D005118:Extraterrestrial Environment; D018525:Germination / Q000528:radiation effects*; D018499:Linear Energy Transfer; D016296:Mutagenesis; D011834:Radiation Monitoring / Q000295:instrumentation; D012062:Relative Biological Effectiveness; D012639:Seeds / Q000528:radiation effects*; D018030:Silver Compounds; D013026:Space Flight / Q000295:instrumentation*; D018531:Spacecraft / Q000295:instrumentation*
chemical_list: D018030:Silver Compounds; C037548:silver chloride