Abstract: 6-8 years old Norway spruce grafting plants from 20-30 years old ortets were grown under either inductive condition, hot and dry (HD) , or non-inductive condition, cool and wet(CW). Next year after treated, 95% of the grafting plants treated under HD condition emerged male cones, 63% of them emerged female cones. While neither male nor famale cones appeared for the CW treated grafting plants. The samples for determination of gibberellins were taken two times. The interval between the two sampling occasions was 8 days. The average amount of GA, in the needles of HD treated plants increased from 6.4ng/g( fresh weight) on the first sampling occasion to 10.9ng by the second occasion, whereas decreased from 4.7ng to 2.7ng for CW treated plants(control). There was a decreasing trend of GA₄ content in both plants HD and CW treated, from 2.3ng and 3.2ng to 0.4ng and 1.7ng respectively. The contents of GA_S and GA₁ was less and only examined in few samples so that any relation between contents of them and flowering was found. The analytical results of GAS contents and its metabolism have been discussed in this paper.

Key words: Gibberellins, Flowering, Norway spruce