Premium
Influence of Auxin on Young's Modulus in Stems and Roots of Pisum and the Theory of Changing the Modulus in Tissues
Author(s) -
Burströum H. G.,
Uhrströum Inger,
Olausson B.
Publication year - 1970
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1970.tb08898.x
Subject(s) - auxin , pisum , elongation , sativum , epicotyl , biophysics , plant stem , botany , elastic modulus , modulus , etiolation , chemistry , materials science , biology , composite material , hypocotyl , biochemistry , ultimate tensile strength , gene , enzyme
The effect of auxin on elastic extensibility has been investigated by means of the resonance frequency melhod in Pisum, sativum . The time lag for the decrease in Young's modulus E, caused by IAA, was between 2 and 3 minutes in etiolated stem internodes. The time lag for growth was about 7 minutes. The measurements of E in root segments were only qualitative owing to the structural characteristics; IAA decreases E in roots as it does in stems, but only in the region where IAA is assumed to enhance elongation. The connexion between elastic modulus and growth is discussed with reference to other investigations. The assumption has been made that a decrease in elastic modulus indicates a change in the cell wall which in some way is conducive to growth (induction of elongation). The theoretical possibilities of changing E have been discussed with reference to the formula for water fluxes. Both a change in a cell wall properly and a change in the cytoplasmic permeability are able to cause a change in E in the same way as auxin does. An early action of auxin must be located in the cell‐wall‐plasmalemma region.