Lateral Root Morphology as an Expression of Sweetgum Seedling Quality
Abstract:Sweetgum seedlings from four open pollinated mother trees were grown in nursery beds infested with one of four vesicular-arbuscular mycorrhizal (VAM) fungi, and with available soil P levels (Bray II) adjusted to 50 ppm. Comparable beds had no VAM fungi present but had their available soil P levels adjusted to about 75, 100, 200, and 300 ppm. When lifted, the seedlings were placed in one of three morphological grades based upon number of permanent lateral roots exceeding 1 mm in diameter: Grade 1 seedlings had more than six roots; grade 2 between four and six roots; grade 3 had fewer than four roots. Approximately 50 percent of all seedlings fell within the inferior root grade 3 classification. Nursery mycorrhizal condition and phosphorus fertilization had no affect upon lateral root morphology of seedlings from the four seedlots. No significant biological differences in seedling heights were observed among the different root grades at lifting but root collar diameter (RCD) varied significantly among the grades in order: grade 1 > grade 2 > grade 3. One year after outplanting, effects of root grade were significant for both height and RCD: grade 1 > grade 2 > grade 3. Early first year seedling dieback and first year survival varied significantly among grades. Dieback percentages for grades 1, 2, and 3 were 41, 67, and 89 percent; survival averages for grades 1, 2, and 3 were 79, 67, and 51 percent. These data suggest that number of lateral roots on a sweetgum nursery seedling is an indicator of probable performance after outplanting. Forest Sci. 32:595-604.
Document Type: Journal Article
Affiliations: Principal Silviculturist, USDA Forest Service, Institute for Mycorrhizal Research and Development, Forestry Sciences Laboratory, Athens, GA 30602
Publication date: September 1, 1986
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- Forest Science is a peer-reviewed journal publishing fundamental and applied research that explores all aspects of natural and social sciences as they apply to the function and management of the forested ecosystems of the world. Topics include silviculture, forest management, biometrics, economics, entomology & pathology, fire & fuels management, forest ecology, genetics & tree improvement, geospatial technologies, harvesting & utilization, landscape ecology, operations research, forest policy, physiology, recreation, social sciences, soils & hydrology, and wildlife management.
Forest Science is published bimonthly in February, April, June, August, October, and December.
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