Effect of Different Cytokinins on Ethylene Production by Mung Bean Hypocotyls in the Presence of Indole‐3‐Acetic Acid or Calcium Ion

Abstract
Kinetin has been shown to act synergistically with indole‐3‐acetic acid (IAA) or calcium ion (Ca2+) to stimulate ethylene production. Several commercially available cytokinins (kinetin, kinetin‐riboside, benzyladenine, benzyladenine‐riboside, isopentenyladenine, isopentenyladenine‐riboside, and zeatin) as well as noncytokinin bases (adenine and xanthine) were administered to mung bean (Phaseolus aureus Roxb.) hypocotyls to study their effects, alone or in combination with IAA or Ca2+, on ethylene production. In the presence of IAA or Ca2+, all cytokinins tested synergistically stimulated ethylene production and were as effective or nearly as effective as kinetin. Noncytokinin bases (adenine and xanthine) were, however, inactive in this system.