Heterotrophic plant cells of three apple cultivars, two pear cultivars, strawberry, and tomato were cultured in vitro. Cell homogenates in the presence of linolenic acid formed n-hexanal, (Z)-3-hexenal, (E)-2-hexenal, and, in one apple cultivar, (Z)-3-hexenol and its acetate. Homogenates of photomixotropic apple cv. Goldparmfine cells contained eight times more (E)-2-hexenal than homogenates of non-green cells.