Studies on the growth and indole-3-acetic acid and abscisic acid content of Zea mays seedlings grown in microgravity.
Measurements were made of the fresh weight, dry weight, dry weight-fresh weight ratio, free and conjugated indole-3-acetic acid, and free and conjugated abscisic acid in seedlings of Zea mays grown in darkness in microgravity and on earth.  Imbibition of the dry kernels was 17 h prior to launch.  Growth was for 5 d at ambient orbiter temperature and at a chronic accelerational force of the order of 3 x 10(-5) times earth gravity.  Weights and hormone content of the microgravity seedlings were, with minor exceptions, not statistically different from seedlings grown in normal gravity.  The tissues of the shuttle-grown plants appeared normal and the seedlings differed only in the lack of orientation of roots and shoots.  These findings, based upon 5 d of growth in microgravity, cannot be extrapolated to growth in microgravity for weeks, months, and years, as might occur on a space station.  Nonetheless, it is encouraging, for prospects of bioregeneration of the atmosphere and food production in a space station, that no pronounced differences in the parameters measured were apparent during the 5 d of plant seedling growth in microgravity.
Schulze
A
A
Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824-1312.
Jensen
P J
PJ
Desrosiers
M
M
Buta
J G
JG
Bandurski
R S
RS
D000040:Abscisic Acid / Q000032:analysis; D005875:Gibberellins / Q000032:analysis; D007210:Indoleacetic Acids / Q000032:analysis; D009929:Organ Size; D010937:Plant Growth Regulators / Q000032:analysis*; D013026:Space Flight; D014893:Weightlessness; D003313:Zea mays / Q000737:chemistry* / Q000254:growth & development*
D005875:Gibberellins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid; D000040:Abscisic Acid