Reproductive Development in Loblolly Pine. Ii. The Effect of Age, Gibberellin Plus Water Stress and Out‐of‐phase Dormancy on Long Shoot Growth Behavior

The effects of age from seed, out‐of‐phase dormancy, and gibberellin treatment with water stress on the reproductive and vegetative development of the long shoot terminal bud were observed. Scions of different ages were grafted onto 1‐yr‐old rootstocks, and the younger scions grew more and produced fewer strobili than older ones. Out‐of‐phase dormancy promoted both male and female flowering at all ages, but the older scions responded better. Gibberellin4/7 plus water stress promoted development of female strobili only. Treatments that promote flowering also increase the size of the resting bud. It is proposed that treatment effects promoting flowering appear to fall into two categories: 1) Those which promote the formation of a resting bud, and 2) those which affect the subsequent development of resting buds which have the potential to develop strobili.