Staining of the Stem Tissue of Plants by Triphenyltetrazolium Chloride

Abstract

Willow twigs, from living trees and shrubs, were immersed in a 1% aqueous soln. of triphenyltetrazolium chloride (TPTZ). Sections from the same twig were heated in a test tube in a boiling bath for 15 min. All unheated sections, except for sumac and mock orange, developed a red color in the cambium layer. The sumac was very highly pigmented. The mock orange showed a rusty red circle around the pith. Heated sections showed neither browning nor reddening. Sections of maple, apple, plum, hawthorn, pine, spruce, cedar, etc., needed about 4 hrs. to develop the red color. The color appeared first in the cambium, but in the maple and apple, the color was seen around the pith as well. Considerable browning preceded the staining in most deciduous spp. Willow sections were stained in 1-2 min., followed by slow color development throughout the phloem. There was no color in the xylem or pith. It is considered that this new application of TPTZ will be of value to determine the viability of trees, shrubs, and cuttings.