Growth and ecophysiology of wide intraspecific balsam poplar (Populus balsamifera L.) hybrids
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Ryan, Natalie Marie
issued: 2015-10-24T06:57:51
issued: 2015
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: The widespread species Populus balsamifera L. exhibits large intra-specific variation in photosynthetic rates and phenology. Northern populations have a tendency towards higher photosynthetic carbon assimilation rates (An) than trees from the south. However, because bud set occurs earlier in northern trees they accomplish far less height growth than do southern trees. Assuming that there are no physiological constraints to combining high An and long growing season, the progeny of intra-specific crosses between northern and southern populations may accomplish more growth in one growing season than their parents (i.e., heterosis). High performing F₁s could be used for a variety of agroforestry projects. Full reciprocal crosses were conducted between individuals from two northern (N) and two southern (S) populations found at the extremes of the P. balsamifera range. Representative selections of progeny and parental material were planted in a greenhouse and in the field and characters including shoot elongation rate, photosynthetic rates, stomatal conductance (gs), water-use efficiency (WUE) leaf mass per area (LMA), internal conductance (gm) in a greenhouse and phenology in the field were evaluated. Although the F₁ families did not display any evidence of heterosis, photosynthetic rates and phenology were uncorrelated in the NxS families, suggesting an uncoupling of traits. Additionally, a number of individuals which possessed a combination of high growth potential and late growth cessation (bud set) were observed and could be useful for a variety of potential deployment areas. The high An in northern populations has been partially attributed to gm, and appears to be a consequence of leaves with greater LMA, which have an increased mesophyll surface area available for carbon uptake. WUE was also correlated with LMA, suggesting that in facilitating CO₂ diffusion for carbon assimilation an increase in gm over an increase in gs provides a clear advantage in not promoting …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/54956
note: GROWTH AND ECOPHYSIOLOGY OF WIDE INTRASPECIFIC BALSAM POPLAR (POPULUS BALSAMIFERA L.) HYBRIDS by Natalie Marie Ryan BSc. with Specialization in Environmental Biology, University of Alberta, 2009 A THESIS SUMBITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Forestry) The University of British Columbia (Vancouver) October 2015  Natalie Marie Ryan, 2015ii Abstract The widespread species Populus balsamifera L. exhibits large intra-specific variation in photosynthetic rates and phenology. Northern populations have a tendency towards higher photosynthetic carbon assimilation rates (An) than trees from the south. However, because bud set occurs earlier in northern trees they accomplish far less height growth than do southern trees. Assuming that there are no physiological constraints to combining high An and long growing season, the progeny of intra-specific crosses between northern and southern populations may accomplish more growth in one growing season than their parents (i.e., heterosis). High performing F1s could be used for a variety of agroforestry projects. Full reciprocal crosses were conducted between individuals from two northern (N) and two southern (S) populations found at the extremes of the P. balsamifera range. Representative selections of progeny and parental material were planted in a greenhouse and in the field and characters including shoot elongation rate, photosynthetic rates, stomatal conductance (gs), water-use efficiency (WUE) leaf mass per area (LMA), internal conductance (gm) in a greenhouse and phenology in the field were evaluated. Although the F1 families did not display any evidence of heterosis, photosynthetic rates and phenology were uncorrelated in the NS families, suggesting an uncoupling of traits. Additionally, a number of individuals which possessed a combination of high growth potential and late growth cessation (bud set) were observed and could…
has type: Thesis/Dissertation
date issued: 2015-11
is shown at: 10.14288/1.0166758
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivs 2.5 Canada
rights URI: http://creativecommons.org/licenses/by-nc-nd/2.5/ca/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/54956