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Physiological and Growth Responses of C 3 and C 4 Plants to Reduced Temperature When Grown at Low CO 2 of the Last Ice Age
Author(s) -
Ward Joy K.,
Myers David A.,
Thomas Richard B.
Publication year - 2008
Publication title -
journal of integrative plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.734
H-Index - 83
eISSN - 1744-7909
pISSN - 1672-9072
DOI - 10.1111/j.1744-7909.2008.00753.x
Subject(s) - photorespiration , photosynthesis , carbon dioxide , abutilon , botany , glacial period , biology , chemistry , zoology , ecology , paleontology , weed
Abstract During the last ice age, CO 2 concentration ([CO 2 ]) was 180–200 μμmol/mol compared with the modern value of 380 μμmol/mol, and global temperatures were ∼8 °C cooler. Relatively little is known about the responses of C 3 and C 4 species to long‐term exposure to glacial conditions. Here Abutilon theophrasti Medik. (C 3 ) and Amaranthus retroflexus L. (C 4 ) were grown at 200 μμmol/mol CO 2 with current (30/24 °C) and glacial (22/16 °C) temperatures for 22 d. Overall, the C 4 species exhibited a large growth advantage over the C 3 species at low [CO 2 ]. However, this advantage was reduced at low temperature, where the C 4 species produced 5× the total mass of the C 3 species versus 14× at the high temperature. This difference was due to a reduction in C 4 growth at low temperature, since the C 3 species exhibited similar growth between temperatures. Physiological differences between temperatures were not detected for either species, although photorespiration/net photosynthesis was reduced in the C 3 species grown at low temperature, suggesting evidence of improved carbon balance at this treatment. This system suggests that C 4 species had a growth advantage over C 3 species during low [CO 2 ] of the last ice age, although concurrent reductions in temperatures may have reduced this advantage.