Idaho's population of Pacific dogwood (Cornus nuttallii Audubon) has declined. Propagation of disease-resistant clones would be useful to horticulturists and conservation biologists. In vitro-derived microshoots, incubated for 1 month on woody plant medium supplemented with 6.04 mm calcium gluconate and 4.44 μm benzyladenine, produced an average of 3.1 axillary microshoots per explant. Up to 62% of the elongated microshoots had rooted ex vitro 5 weeks following a 4.5%IBA talc dip. Plantlets resumed shoot growth within 2 months of acclimatization, and 70% survived after 1 year. This protocol is more rapid and efficient than propagation by layering or rooting the difficult-to-root stem cuttings of this species. Chemical names used: 2,3,4,5,6-pentahydroxy-caproic acid (calcium gluconate), benzyladenine (BA), 3-indolebutyric acid (IBA).

Application. Coating the interior walls of seedling containers with cupric carbonate produces seedlings of three western conifer species with more lateral roots in the upper portion of the root plug one season after outplanting. These seedlings develop a more natural root system which may improve seedling stability and growth.Abstract. Containers deform seedling root systems and have a potential to inhibit tree growth after outplanting. Ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa), western white pine (Pinus monticola Dougl. ex D. Don), and Douglas-fir (Pseudotsuga menziesii vat. glauca (Beissn.) Franco) were grown in containers coated with latex paint containing different concentrations of cupric carbonate and outplanted in a forest. Treatment effects on seedling growth and root morphology were determined after one growing season in the field. Seedling height was unrelated to treatment and stem diameter was not significantly affected (p ~< 0.05). New root growth in the upper portion of the root plug was significantly increased (p ~< 0.05). The optimal concentration of cupric carbonate for seedling root growth in the upper portion of the root plug was estimated by multiple regression.

-Prior to sowing seeds, three controlled-release fertilizers (fast release (FR), moderate release (MR) and slow release (SR)) were incorporated into the growing media at rates of 0.8, 1.6 or 3.2 g as supplements to nursery supplied soluble fertilizer to grow containerized ponderosa pine (Pinus ponderosa Doug. ex Laws) seedlings in the greenhouse. At lifting, the stem diameter, height and total mass of fertilized seedlings ranged from 14 to 29%, 15 to 22%, and 39 to 100% larger than those of the unfertilized seedlings, respectively. FR provided more balanced nutrients than did MR or SR. The root growth potentials of ponderosa pine treated with 3.2 g of MR or SR were much lower than those of other treatments, indicating that a 3.2 g rate of MR or SR was too high for the seedlings. The estimated best dosages for maximum caliper and height growth were 0.8, 2.2 and 2.0 g for FR, MR and SR fertilizers, respectively. Pinus ponderosa

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Douglas-fir (Pseudotsuga menziesii var. glauca) ponderosa pine (Pinus ponderosa var. ponderosa), and western white pine (Pinus monticola) where chemically root pruned with cupric carbonate (CuCO3) during greenhouse production. The interior walls of Styroblock 4A® and Ray Leach® pine cell containers (each 66 cm³) were coated with latex paint containing CuCO3 at concentrations of 0, 30, 100, or 300 g/l. Seedlings were potted after one growing season, initiating a standard root growth potential test (Duryea 1984). The number and length of new roots more than 1 cm in length were measured. Seedling root systems increased in total root number and length, especially in the upper segments of the root plug, as a result of chemical root pruning. Seedling height and caliper were unaffected by the cupric carbonate treatments during the production phase, and a latex paint carrier did not decrease seedling growth. West. J. Appl. For. 4(1):15-17, January 1989.