Zea mays L. and Taxodium distichum L. seedlings were grown for 35 days in sand or 3:1 milled pine bark:sand media in 0.7 liter containers. Containers were painted on interior surfaces with 100 g Cu(OH)2/liter or 200 g Cu(OH)2/liter latex carrier (Spin Out™) or not. Five seedlings of each treatment combination were watered daily from 9.5 liter reservoirs with 100 ml of recycled fertilizer (20N-8.7P -16.6K. pH 6.0) solution initially containing 0.036 mg Cu/liter. Fertilizer solutions containing 0.036, 5, 10, 100, or 1000 mg Cu/liter were used to develop toxicity response curves with additional seedlings. Growth of both species in both media was increased by Spin Out treatments. Soluble Cu content of the recycled solution from Spin Out treated containers increased slightly (<1.2 mg/liter) during the experiment. Soluble Cu in leachate from Cu-treated containers ranged from 0.2 to 5 mg/liter with sand and from 0.30 to 1.2 mg/liter with bark. Soluble Cu in leachatc from non-treated containers ranged from 0.02 to 0.40 mg/liter with sand and 0.10 to 0.86 mg/liter for bark media.
Larry J. Shoemake and Michael A. Arnold
Seven half-sib families of Platanus occidentalis L., either genetically improved selections (TFS-09, TFS-24, WV-10, WV-14) or non-improved selections (Brazos-C, Brazos-D, Putnam), were grown outdoors in 2.3-L to 9.1-L containers, then transplanted in fall, spring, or summer to assess root regeneration potential (RRP) and initial (2 year) post-transplant landscape growth. TFS-09, TFS-24, Brazos-C, and Brazos-D were Texas selections, while WV-10, WV-14, and Putnam were from Tennessee and Kentucky. Generally, local half-sib families grew more rapidly than geographically distant families and some genetically improved selections grew more rapidly than non-improved selections, both in the landscape and nursery. Rapid growth of new roots and transplanted root dry matter were more consistently associated with successful transplant establishment across families than other measures of RRP. Survival was reduced after summer vs. spring or fall transplant.
Larry J. Shoemake and Michael A. Arnold
Ninety seedlings from each of seven half-sib families of sycamore (Platanus occidentalis L.) were grown to marketable size in 9.1-liter containers in College Station, Texas. Dry matter partitioning was assessed with 10 seedlings each of four half-sib families grown in 4.7-liter containers. Half-sib families included selections native to Brazos County, Texas, and Putnam County, Tenn., and four half-sib families from the Westvaco Corp. (WV) or Texas Forest Service (TFS) tree improvement programs. Families could be separated into three groups with TFS-09 attaining a significantly greater height than other families, while Brazos-D, Brazos-C, and TFS-24 were intermediate and WV-10 and WV-14 were shortest. Contrary to previous field production studies, a weak inverse correlation (R 2 = –0.19, P > 0.01) was observed between the number of cuts required to remove multiple leaders and plant height, perhaps due to episodic shoot elongation in south Texas conditions vs. a single flush in northern regions. Corrective pruning removed more dry matter from TFS-09 than from Brazos-D, Brazos-C, and Putnam seedlings. Total dry weights of TFS-09 and Brazos-C were greater than WV-14 or Putnam seedlings.
Michael A. Arnold, Larry J. Shoemake, and Mitchell W. Goyne
Transplant studies were conducted on Taxodium distichum L., Platanus occidentalis L., Quercus shumardii Buckl., Fraxinus velutina Torr., and Chilopsis linearis (Cav.) Sweet seedlings grown in 2.2- to 9.1-L black plastic containers. Effects of half-sib family selection on post-transplant root regeneration potential (RRP) and field establishment were investigated with P. occidentalis. Taxodium distichum, Q. shumardii, and P. occidentalis were used to determine seasonal variation in relationships among RRP characteristics and measures of successful transplant establishment. Post-transplant effects of avoidance of circling root development vs. remediation practices were investigated with Q. shumardii. Effects of container media composition on field establishment and RRP of container-grown plants were studied using F. velutina and C. linearis. Impacts of rotation time on RRP and field establishment were investigated with T. distichum. Rates of RRP were the measure most consistently linked to improved post-transplant shoot growth of P. occidentalis. Utilization of locally adapted genotypes and avoidance of summer transplant were important in establishment of P. occidentalis and T. distichum. Increased small diameter root regeneration was linked to reduced water stress during transplanting of Q. shumardii. Physical characteristics of the container media impacted initial post-transplant growth of F. velutina and C. linearis.
Larry J. Shoemake, Michael A. Arnold, and Fred T. Davies Jr.
A series of six experiments was conducted over eight years to investigate impacts of provenance on transplant establishment in landscapes and the role of adventitious root regeneration in differential genotypic responses during establishment of Platanus occidentalis L. Fall, spring, and summer transplants of container-grown half-sib families (HSF = seedlings derived from a single mother tree with unknown male parentage), including two selections native to Brazos County, Texas (Brazos-C, Brazos-D), one native to Cookeville, Tenn. (Cookeville), two Kentucky/Tennessee HSF from the Westvaco Corp. (WV-10, WV-14), and two Texas HSF from the Texas Forest Service tree improvement program (TFS-09, TFS-24), were established to determine field/landscape growth responses. Subsequent studies were conducted to investigate differential leaf gas exchange responses of TFS-09 and Cookeville during moderate water deficits and to determine root regeneration potential (RRP) responses of TFS-09, Brazos-C, WV-14, and Cookeville HSF following fall, spring, and summer transplant. To investigate consistency of within-family genotypic responses and to determine relationships among adventitious root initiation from shoot cuttings, RRP, and landscape establishment, five seedlings of TFS-09 and five from Cookeville HSF were clonally propagated and ramets tested under field and RRP conditions similar to those with seedling-derived plants. Regionally native HSF consistently grew taller, had larger trunk diameters, and often had greater survival during the first 3 years in the landscape than HSF not native to the region in which the studies were conducted. Rapidity of root regeneration among HFS at the time of transplant was the best root growth related predictor of successful landscape establishment. Some growth advantages were found using genetically improved HSF, but not as consistent an improvement as with the use of seedlings from regional provenances. Within-family variation in landscape performance was greater with nonregional Cookeville clones than with regional TFS-09 clones, however there was overlap among the more vigorous Cookeville clones and the least vigorous TFS-09 clones. Increased rapidity of root regeneration and drought adaptations related to leaf morphology and gas exchange characteristics may be involved in enhanced growth responses of Texas regional genotypes. No consistent relationships were found among adventitious rooting responses from shoot cuttings and subsequent RRP of the same genotypes from root tissues or their growth during the first 3 years in landscapes.