Adventitious rooting and physiology of stem cuttings of loblolly pine

Two separate series of experiments were conducted to develop protocols for clonal propagation of loblolly pine (Pinus taeda L.) by stem cuttings. The first series of experiments were conducted to test the efficacy of two containerized production systems on rooting percentage, root system morphology, and first year field growth of rooted stem cuttings of loblolly pine. The second series of experiments focused on the effect of the rooting environment on adventitious root formation to define a propagation protocol with broad application that stimulates rooting among several rooting environments.; In the first series of experiments, three studies were conducted to test adventitious rooting of juvenile hardwood (dormant) or softwood (succulent) stem cuttings of six unrelated full-sib families of loblolly pine in various sizes of JiffyRTM Forestry Peat Pellets or Ray Leach Conetainers(TM) and the subsequent effect on first year field growth after outplanting. Controls in all experiments were Ray Leach Super Cells filled with a medium of 2 peat: 3 perlite (v/v). After adventitious rooting in the greenhouse and 12 months of field growth, all plants, with the exception of plants produced in one Jiffy pellet size, were shorter than the controls and had less root dry weight (DW) and shoot DW. Results suggest that preplant root DW is an important predictor of first year field performance.; In the second series of experiments, six studies were conducted. Four studies investigated the influence of cutting water potential (Psi cut) on rooting of juvenile dormant and succulent stem cuttings of loblolly pine propagated under varying substrate water potentials (Psisub) and volumes of mist application (mist levels).; The final two studies of the second series of experiments investigated the relationships between mist application, vapor pressure deficit (VPD), Psi cut, and rooting percentage of dormant or succulent stem cuttings of loblolly pine. In addition, net photosynthesis at ambient conditions (A ambient) and stomatal conductance (gs) of succulent stem cuttings were measured during adventitious root formation to determine their relationship to rooting percentage. (Abstract shortened by UMI.)...