Hormone Treatment Promoting Flower Formation of Clone Seed Orchard of Pinus tabulaeformis Carr.

In order to increase the quantity of female flowers and male flowers in clonal seed orchard of Pinus tabulaeformis,an experiment about the influences of different extraneous hormones of Gibberellin GA4+7,6-Benzyl Aminopurine,and Chlormequat Chloride on seed trees was set up.The results showed that the numbers of male flowers and male flowers were increased obviously by the prouer hormone treating and there were no significant differences among clones.The promoting effects of hormone on promoting female strobious were significant at different months,which was the best in June.GA4+7was the best one for promoting the quantity of female strobious 6-BA was the second and CCC was the third.GA4+7was also the best one for promoting the quantity of male strobilus.However,CCC was the second and 6-BA was the third.Moreover,there was significant difference about the effects between GA4+7 and the other two kinds of hormones for promoting the male strobious.There were significant differences about the effects of the hormones at different concentrations.For promoting female strobilus production,the most effective concentration was 500 mg/L,the concentration of 1 000 mg/L was the best for promoting male strobilus production.