Evolutionary context for understanding and manipulating plant responses to past, present and future atmospheric [CO2]

• Published in: Philosophical transactions of the Royal Society of London. Series B. Biological sciences 2012-02, Vol.367 (1588), p.613-629
• Main Authors: Leakey, Andrew D. B., Lau, Jennifer A.
• Format: Article
• Language: English
• Subjects: Adaptation; Adaptation, Physiological; Atmosphere; Atmospherics; Biological Evolution; Carbon Dioxide - metabolism; Climate Change; Crops, Agricultural - enzymology; Crops, Agricultural - genetics; Crops, Agricultural - physiology; Ecological competition; Evolution; Fitness; Growth traits; Phenotypic traits; Photosynthesis; Plant adaptation; Plant Leaves - enzymology; Plant Leaves - metabolism; Plant Leaves - physiology; Plants; Plants - enzymology; Plants - genetics; Plants - metabolism; Productivity; Quantitative genetics; Review; Ribulose-Bisphosphate Carboxylase - metabolism; Selection, Genetic; Time Factors; Yield
• ISSN: 0962-8436; 1471-2970
• DOI: 10.1098/rstb.2011.0248

Variation in atmospheric [CO 2 ] is a prominent feature of the environmental history over which vascular plants have evolved. Periods of falling and low [CO 2 ] in the palaeo-record appear to have created selective pressure for important adaptations in modern plants. Today, rising [CO 2 ] is a key component of anthropogenic global environmental change that will impact plants and the eco-system goods and services they deliver. Currently, there is limited evidence that natural plant populations have evolved in response to contemporary increases in [CO 2 ] in ways that increase plant productivity or fitness, and no evidence for incidental breeding of crop varieties to achieve greater yield enhancement from rising [CO 2 ]. Evolutionary responses to elevated [CO 2 ] have been studied by applying selection in controlled environments, quantitative genetics and trait-based approaches. Findings to date suggest that adaptive changes in plant traits in response to future [CO 2 ] will not be consistently observed across species or environments and will not be large in magnitude compared with physiological and ecological responses to future [CO 2 ]. This lack of evidence for strong evolutionary effects of elevated [CO 2 ] is surprising, given the large effects of elevated [CO 2 ] on plant phenotypes. New studies under more stressful, complex environmental conditions associated with climate change may revise this view. Efforts are underway to engineer plants to: (i) overcome the limitations to photosynthesis from today's [CO 2 ] and (ii) benefit maximally from future, greater [CO 2 ]. Targets range in scale from manipulating the function of a single enzyme (e.g. Rubisco) to adding metabolic pathways from bacteria as well as engineering the structural and functional components necessary for C 4 photosynthesis into C 3 leaves. Successfully improving plant performance will depend on combining the knowledge of the evolutionary context, cellular basis and physiological integration of plant responses to varying [CO 2 ].