Ethane production by homogenates of Phaseolus vulgaris L. cv. Harvester was studied. The precursor of ethane was identified as linolenic acid. The liberation of ethane was optimum at pH 4.2 and was highest from homogenates of leaves and apical buds. When roots were homogenized in linolenic acid solution, ethane and ethylene production were stimulated. In corn root homogenates, ethylene biosynthesis was stimulated nearly 8-fold by linolenic acid. The enzyme responsible for ethane production from oat root homogenates was soluble and had a high molecular weight.