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Gravity sensing in oat coleoptiles: scatter in growth orientation under different g ‐conditions
Author(s) -
JOHNSSON A.,
CHAPMAN D. K.,
BROWN A.,
JOHNSONGLEBE C.,
KARLSSON C.,
HEATHCOTE D. G.
Publication year - 1993
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.1993.tb00495.x
Subject(s) - coleoptile , avena , gravitropism , physics , gravitational acceleration , logarithmic scale , chemistry , mathematics , botany , biology , gravitation , biochemistry , classical mechanics , arabidopsis , mutant , gene , acoustics
Dark‐grown oat seedlings depart from the expected vertical orientation, suggesting that the coleoptile is less responsive to the lateral component of a gravitational stimulus than would be expected. This phenomenon was studied by investigating the gravitropic curvatures of oat ( Avena sativa L. cv. Seger) coleoptiles at 10 g and over a range of longitudinally applied centripetal accelerations up to 19·4g. In most experiments, the plants were grown and observed at a particular g ‐level throughout the experiment. Time‐lapse video recordings permitted studies of the scatter, measured as the variability of the plants' angle from the vertical (or root mean square value, RMS). The coleoptiles' heights at the end of the experiments were not significantly altered under the centrifugation. Scatter increased with plant age and decreased with increasing g. It decreased in an almost linear fashion as a function of the logarithm of the g ‐acceleration. In a series of experiments, the g ‐level was changed from 10 g to a higher test g ‐acceleration. The scatter was then reduced within half an hour after the g ‐transition. It is pointed out that the experiments confirm that the scatter is g ‐related but that it was not predicted quantitatively by present theories of the oat coleoptile's gravitropic response kinematics.