Gibberellins in mature apple seeds - contaminants?

Evidence is presented that gibberellins A4 and A7, previously identified (Sinska, I., Lewak, St., Gaskin, P., MacMillan, J., Planta 114, 359-364, 1973) in extracts of mature apple (Pyrus malus L.) seeds, were present primarily as contaminants. The facts supporting this conclusion are: a) the ratio of GA4 to GA7 was similar to that of a standard mixture; b) the concentrations were extremely high; and c) the ratio of GA4 to GA7 did not change during stratification, as had been reported when extracts were bioassayed (Sinska, I., and Lewak, St., Physiol. Vég. 8, 661-667, 1970).