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Home → Publications → National Nursery Proceedings → 1988 → Effect of Paclobutrazol on Conifer Seedling Morphology and Field Performance

Effect of Paclobutrazol on Conifer Seedling Morphology and Field Performance

Paclobutrazol, an inhibitor of gibberellin biosynthesis, significantly reduced the growth of jack pine, red pine, and eastern larch bareroot nursery seedlings. Application in August prior to the final complete year in the nursery was more effective than application in April of the final complete year. In many cases, the higher concentrations of paclobutrazol (10 20 mg/plant) retarded root growth as well as shoot growth, and retarded first year growth in the field. One treatment (red pine, 5 mg/tree, applied in April) resulted in a 20% reduction in seedling height, 33% increase in root dry weight, and 35% reduction in shoot:root ratio, without carryover effects to the field. Further work is needed to optimize the shoot and root growth responses to paclobutrazol and to control its persistence in the soil.


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Author(s): W. J. Rietveld

Publication: National Nursery Proceedings - 1988

Event: Combined Meeting of the Western Forest Nursery Associations
1988 - Vernon, CAN