Through the inter-transferring with flower-induction and vegetative bud-induction medium, the critical period of floral differentiation in the decapitated seedlings of cucumber was founded to be the 5~6 th day after culture (3~4 th day after decapitation). The results of changes of endogenous hormone contents at early stage of floral differentiation in cotyledonary nodes of cucumber seedlings after decapitation were as follows: The contents of IAA and ZT in cotyledonary nodes of the cucumber seedlings withi...