title: Genotypic effects of fertilization on seedling sweetgum biomass allocation, N uptake, and N use efficiency.
abstract: Screening and selecting tree genotypes that are responsive to N additions and that have high nutrient use efficiencies can provide better genetic material for short-rotation plantation establishment. A pot experiment was conducted to test the hypotheses that (1) sweetgum ( Liquidambar styraciflua L.) families have different patterns in biomass production and allocation, N uptake, and N use efficiency (NUE), because of their differences in growth strategies, and (2) sweetgum families that are more responsive to N additions will also have greater nutrient use efficiencies. Seedlings from two half-sib families (F10022 and F10023) that were known to have contrasting responses to fertility and other stress treatments were used for an experiment with two levels of N (0 vs. 100 kg N/ha equivalent) and two levels of P (0 vs. 50 kg P/ha equivalent) in a split-plot design. Sweetgum seedlings responded to N and P treatments rapidly, with increases in both size and biomass production, and those responses were greater with F10023 than with F10022. Growth response to N application was particularly strong. N and P application increased the proportional allocation of biomass to leaves. Under increased N supply, P application increased foliar N concentration and content, as well as total N uptake by the seedlings. However, NUE was decreased by N addition and was higher in F10023 than in F10022 when P was not limiting. A better understanding of genotype by fertility interactions is important in selecting genotypes for specific site conditions and for optimizing nutrient use in forestry production.
authors.affiliation: Center for Enhanced Forest Management, Department of REnewable Resources, University of Alberta, Edmonton, Canada. scott.chang@ualberta.ca
authors.forename: S X
authors.initials: SX
authors.lastname: Chang
authors.forename: D J
authors.initials: DJ
authors.lastname: Robison
mesh_terms: D018533:Biomass; D005298:Fertility / Q000502:physiology; D005306:Fertilization / Q000502:physiology*; D005838:Genotype; D031317:Liquidambar / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism* / Q000494:pharmacology; D010758:Phosphorus / Q000378:metabolism / Q000494:pharmacology; D018514:Plant Structures / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D012621:Seasons; D036226:Seedlings / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D014197:Trees / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology
chemical_list: D010758:Phosphorus; D009584:Nitrogen