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Warming and elevated CO 2 affect the relationship between seed mass, germinability and seedling growth in Austrodanthonia caespitosa , a dominant Australian grass
Author(s) -
HOVENDEN MARK J.,
WILLS KAREN E.,
CHAPLIN REBECCA E.,
VANDER SCHOOR JACQUELINE K.,
WILLIAMS AMITY L.,
OSANAI YUI,
NEWTON PAUL C. D.
Publication year - 2008
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2008.01597.x
Subject(s) - seedling , germination , shoot , horticulture , population , temperate climate , biology , agronomy , zoology , botany , demography , sociology
While the influence of elevated CO 2 on the production, mass and quality of plant seeds has been well studied, the effect of warming on these characters is largely unknown; and there is practically no information on possible interactions between warming and elevated CO 2 , despite the importance of these characters in population maintenance and recovery. Here, we present the impacts of elevated CO 2 and warming, both in isolation and combination, on seed production, mass, quality, germination success and subsequent seedling growth of Austrodanthonia caespitosa , a dominant temperate C 3 grass from Australia, using seeds collected from the TasFACE experiment. Mean seed production and mass were not significantly affected by either elevated CO 2 or warming, but elevated CO 2 more than doubled the proportion of very light, inviable seeds ( P < 0.05) and halved mean seed N concentration ( P < 0.04) and N content ( P < 0.03). The dependence of seed germination success on seed mass was affected by an elevated CO 2 × warming interaction ( P < 0.004), such that maternal exposure to elevated CO 2 or warming reduced germination if applied in isolation, but not when applied in combination. Maternal effects were retained when seedlings were grown in a common environment for 6 weeks, with seedlings descended from warmed plants 20% smaller ( P < 0.008) with a higher root : shoot ratio ( P < 0.001) than those from unwarmed plants. Given that both elevated CO 2 and warming reduced seed mass, quality, germinability or seedling growth, it is likely that global change will reduce population growth or distribution of this dominant species.