IAA oxidase, peroxidase, and barrier zone formation in red maple

Abstract

Wounding the cambium of red maple {Acer rubrum L.) altered peroxidase lsoenzymes and enhanced the activities of peroxidase and indole-3-acetic acid oxidase in homogenates of adjacent cambial tissue. Four separate experiments were conducted, in May and July in each of two successive years. Wounds made m July caused greater increases in enzyme activity than those made in May. Alterations in peroxidase lsoenzyme pattern were consistent for all experiments. These changes are lntrepretable as aspects of the molecular regulation of barrier zone formation.

Verticillium wilt caused by Verticillium dahliae in woody plants with emphasis on olive and shade trees

“…Wall 4 is the strongest and referred to as the Bbarrier zone^that is produced by cambial activity after injury or infection of the existing xylem, and separates the tissue present at the time of infection from new, uninfected tissue (Shigo 1984). It has been reported that, shifts in enzymes and growth regulators in the vascular cambium result in the formation of barrier zone (Shigo 1984;Shigo and Dudzik 1985;Smith and Shortle 1990;Tippett and Shigo 1981). Also a waxy layer of suberin may be synthesized at the boundary between healthy and infected sapwood (Pearce 1990).…”