Studies in seed dormancy : VI. The effects of growth retardants on the gibberellin content and germination of chilled seeds of Corylus avellana L.

The germination at 20°, of hazel seeds which had been chilled, was significantly inhibited by 10(-4) M solutions of ABA and of five substances which are considered to be inhibitors of gibberellin synthesis, namely CCC, AMO 1618, Phosphon D, B-995 and C-011. When the endogenous gibberellins were extracted from chilled seeds which had been held at 20° for 7 days in the presence of 10(-4) M solutions of three of the most effective inhibitors of germination (Phosphon D, B-995 and C-011) it was found that gibberellin accumulation had been substantially inhibited. It is postulated that the inhibition of gibberellin synthesis inhibits the germination of previously chilled hazel seeds.