Compression method for measurement of stress-relaxation properties of plant cell walls with reference to plant hormone actions

A compression method for measurement of stress-relaxation proper- ties of the cell wall of storage tissues was developed, and the stress relaxation for the cell wall of Jerusalem artichoke tuber tissue was found to be represented by the equation S = b p · log ( t + T mp ) ( 1 + t p t + T mp ) t + T mp t p ( t + T op ) ( 1 + t p t + T op ) t + T op t p + c p where S is stress, t is time and b_p, T_op, T_mp and c_p are constants. A synthetic auxin, 2,4-dichlorophenoxyacetic acid, induced cell wall loosening represented by a decrease in T_op prior to the induction of expansion growth. Auxin and gibberellin synergistically stimulated the increase in b_p and the decrease in c_p in 2–3 days.