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INFLUENCE OF THE TONIC EFFECT OF GRAVITATION AND AUXIN ON CELL ELONGATION AND POLARITY IN ROOTS
Author(s) -
Burström H. G.
Publication year - 1969
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1969.tb09714.x
Subject(s) - elongation , auxin , biology , shoot , cell division , polarity (international relations) , botany , tonic (physiology) , darkness , root hair , biophysics , apical cell , gravitropism , microbiology and biotechnology , cell , arabidopsis , biochemistry , neuroscience , mutant , materials science , ultimate tensile strength , metallurgy , gene
The influence of a longitudinal (tonic) gravitational force and of auxin on the pattern of growth and cell polarity has been studied on intact roots of wheat seedlings. A klinostat technique was used for controlling gravitation. Growth in length was evaluated as cell division activity, rate of cell elongation (μ/h) and duration of elongation (h). Exogenous auxin (1‐NAA) increases the rate of cell elongation in all concentrations tested (10 −8 — 3 × 10 −7 m ) and shortens the time of elongation with increasing concentration. It promotes rate of cell elongation in roots as it does in shoots. It also accentuates the polar insertion of root hairs and their growth. The tonic effect of gravitation resembles that of an increase in auxin both in light and darkness. The results are discussed in relation to plagiotropic growth of roots, root growth promotions by auxin, and the difference between root and shoot growth.