Evidence for an Ethylene Requirement to Reduce Soaking Injury in Bean Seeds and the Beneficial Effect of Heavy Metals

In addition to CO2, low concentrations, in decreasing order of effectiveness, of Ag, Ni, Hg, Zn, Co, Pb, and Cu salts tended to reduce soaking injury in bean seeds. Their effects did not appear to be due to ethylene antagonism. The CO2 effect was not related to it lowering the pH of the soaking solution. Soaking injury was aggravated by L-a-(2-aminoethoxyvinyl) glycinehydrochloride (AVG) and 2,5-norbornadiene (NBD) and this effect was reversed by ethrel. Soaking in the presence of an ethylene absorbant Hg(CIO4)2 increased injury. The beneficial effect of CO2 was diminished by NBD and this was reversed by ethrel. Ethrel and ethylene tended to decrease soaking injury. Injurious treatments resulted in less ethylene release by soaked seeds than beneficial treatments. It is concluded that ethylene does not cause soaking injury but appears to be partially required for its prevention.