title: Phonolic components of the primary cell wall and their possible rôle in the hormonal regulation of growth.
abstract: The insoluble cell wall polymers of cultured spinach cells contained esterified ferulic acid at 2-5 mg g(-1) dry weight. Gibberellic acid (GA3, 10(-11)-10(-6) M) promoted the expansion of these cells and simultaneoulsy suppressed peroxidase secretion, reduced the activity of cellular phenylanine ammonia-lyase and favoured the accumulation of wall-esterified ferulate and of extracellular soluble phenolic aglycones. When growth was prevented with 0·7 M sorbitol, GA3 still evoked the phenolic and peroxidase effects. It is suggested that peroxidase restricts growth by rigidifying the cell wall in two ways: (a) covalently by catalysing the conversion of feruloyl side-chains into diferuloyl cross-links and (b) non-covalently by catalysing the conversion of soluble phenolics into hydrophobic quinones (or polymers). GA3 is hypothesised to prevent this rigidification by inhibiting peroxidase secretion.
authors: Botanical Laboratories, University of Leicester, LE1 7RH, Leicester, U.K..
authors: S C
authors: SC
authors: Fry