Comparison of ph Changes and Elicitor Induced Production of Glyceollin Isomers in Soybean Cotyledons

During the incubation of soybean cotyledons with Pmg-elicitor for 22 hours the pH of the diffusion droplets increases from 7.2to8.3.This pH-shift is a precondition for the formation of the typical red colour of the diffusion droplet. After inhibiting the pH-shift by the use of 100mM phosphate or Tris buffer instead of 10 mM buffer as solvent for the elicitor, the red colour is no longer formed with the exeption of 100mM Ammediol buffer. However, the normal pattern of pterocarpan induction can be measured in the absence of the red colour in the diffusion droplet.Tris and Ammediol buffers exhibited a smaller pterocarpan induction as compared to phosphate buffer as solvent for the Pmg-elicitor.