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oai:www.ideals.illinois.edu:2142/22945 2023-07-10 col_2142_5131 col_2142_16357 com_2142_5130 com_2142_16356 com_2142_8913 com_2142_8903

DeLucia, Evan H. Naidu, Shawna Lynn 2011-05-07T13:56:46Z 2011-05-07T13:56:46Z 10000-01-01 1996 The purpose of my research was to test the hypothesis that if shade-grown deciduous hardwood saplings respond positively to late-season canopy gaps, then morphological and physiological changes at both the organ and whole-plant level will result in greater carbon gain of saplings exposed to gaps relative to saplings remaining in the shade; that is, shade-developed saplings will acclimate to late-season canopy gaps. Late-season canopy gap formation was simulated by growing potted saplings in the forest understory and moving them to a naturally occurring canopy gap after leaf development was completed in the shade. A series of experiments with the same basic experimental design was conducted on up to four species of temperate deciduous hardwoods: red oak (Quercus rubra L.), sugar maple (Acer saccharum Marsh.), tulip poplar (Liriodendron tulipifera L.), and white ash (Fraxinus americana L.). Physiological acclimation responses included higher photosynthetic rates in shade-developed foliage upon exposure to higher irradiance and temperature conditions within the gap for each species. However, the magnitude of this change and associated physiological responses varied among species. In general, the increase in photosynthetic rate was correlated with increased stomatal conductance and leaf nitrogen content and, for red oak, decreased susceptibility to photoinhibition. Morphological acclimation responses also varied among species, and included greater allocation to new leaf production and root production after exposure to a gap. Species such as red oak, which acclimated to canopy gaps (increased carbon gain within the season of gap formation), demonstrated coordinated changes in both physiological and morphological mechanisms of acclimation. Conversely, sugar maple had a much more limited acclimation response, reflected in a greater susceptibility to photoinhibition and stomatal limitations to photosynthesis of shade-developed foliage, and limited production of new leaves within the gap. Interspecific comparisons suggest that acclimation involves a suite of coordinated processes rather than trade-offs between mutually exclusive mechanisms of acclimation. Made available in DSpace on 2011-05-07T13:56:46Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9702620.pdf: 6202151 bytes, checksum: c100a99fb5595f0abd265374689cf392 (MD5) Previous issue date: 1996 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T15:01:06Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:28:58-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission ETDs are only available to UIUC Users without author permission U of I Only 9780591089301 AAI9702620 (UMI)AAI9702620 http://hdl.handle.net/2142/22945 eng Copyright 1996 Naidu, Shawna Lynn Biology, Botany Biology, Ecology Agriculture, Forestry and Wildlife Biology, Plant Physiology Coordination of physiological and morphological acclimation of shade-grown tree saplings to late-season canopy gap formation text Biology, Botany Plant Biology Plant Biology Biology, Plant Physiology University of Illinois at Urbana-Champaign Dissertation Ph.D.