A Bioassay for Alfalfa Saponins Using the Fungus, <i>Trichoderma viride</i> Pers. ex Fr.¹

Abstract

Extracted alfalfa saponins and leaf meal extracts from alfalfa influenced the growth rate of some fungi more than others. Of seven fungi whose growth rate was studied on media to which different concentrations of extracted alfalfa saponins or Leeben, a commercial saponin, were added, only Trichoderma viride was fonnd highly sensitive at concentrations below 1 mg of saponin per milliliter of medium. A correlation coefficient of —0.952** was found between the growth of T. viride on 2% potato‐dextrose‐agar containing leaf meal extracts from 36 F 1 and S 1 plant families and saponin percentage. This, together with a correlation coefficient of —0.922** between the growth of T. viride on media containing leaf meal extracts from individual alfalfa plants and saponin percentage, suggests the use of T. viride for bioassays for saponins.