The role of lipases in the germination of dormant apple embryos.

Changes in the activity of alkaline and acid lipases were studied during the culture of embryos isolated from dormant apple (Pyrus malus L.) seeds. Light and treatment with gibberellins (GAs) and with AMO-1618, an inhibitor of GA biosynthesis, influenced the activity of both enzymes.

Gibberellins and the photosensitivity of isolated embryos from non-stratified apple seeds.

The phytochrome system is responsible for the photosensitivity of dormant, isolated apple embryos in culture. Maximum photosensitivity occurs on the second day of culture and it is unaffected by gibberellins (GAs) in concentrations below 10(-4)M. Higher concentrations of GA decrease the photosensitivity.