Atmospheric CO2 enrichment alters energy assimilation, investment and allocation in Xanthium strumarium

• Published in: The New phytologist Vol. 166; no. 2; pp. 513 - 523
• Main Authors: Nagel, Jennifer M., Wang, Xianzhong, Lewis, James D., Fung, Howard A., Tissue, David T., Griffin, Kevin L.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science 01-05-2005; Blackwell Science Ltd; Blackwell
• Subjects: allocation; Animal, plant and microbial ecology; Applied ecology; atmosphere; Atmosphere - chemistry; Atmospherics; Bioenergy; Biological and medical sciences; Biomass; Biomass energy production; Biomass production; Carbon dioxide; Carbon Dioxide - physiology; carbon dioxide enrichment; construction cost (CC); Construction costs; Ecotoxicology, biological effects of pollution; Effects of pollution and side effects of pesticides on plants and fungi; elevated CO2; energy; energy assimilation; energy metabolism; Energy Metabolism - physiology; Fruit - physiology; Fundamental and applied biological sciences. Psychology; photosynthesis; photosynthetic energy-use efficiency; Plant Leaves - physiology; Plant roots; Plant Roots - physiology; Plant Stems - physiology; Plants; Stems; Xanthium - metabolism; Xanthium - physiology; Xanthium strumarium; Xanthium strumarium (common cocklebur); allocation; construction cost (CC); Growth; Resource allocation; Carbon dioxide; Biomass; Compositae; Cost benefit analysis; Xanthium strumarium; Energy balance; Medium enrichment; elevated CO2; Dicotyledones; Angiospermae; Spermatophyta; Models; Photosynthesis; Climate modification; Xanthium strumarium (common cocklebur); energy
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/j.1469-8137.2005.01341.x

• Energy-use efficiency and energy assimilation, investment and allocation patterns are likely to influence plant growth responses to increasing atmospheric CO2 concentration ([ CO2]). Here, we describe the influence of elevated [ CO2] on energetic properties as a mechanism of growth responses in Xanthium strumarium. • Individuals of X. strumarium were grown at ambient or elevated [ CO2] and harvested. Total biomass and energetic construction costs (CC) of leaves, stems, roots and fruits and percentage of total biomass and energy allocated to these components were determined. Photosynthetic energy-use efficiency (PEUE) was calculated as the ratio of total energy gained via photosynthetic activity (A total) to leaf CC. • Elevated [ CO2] increased leaf A total, but decreased CC per unit mass of leaves and roots. Consequently, X. strumarium individuals produced more leaf and root biomass at elevated [ CO2] without increasing total energy investment in these structures ( CC total). Whole-plant biomass was associated positively with PEUE. Whole-plant construction required 16.1% less energy than modeled whole-plant energy investment had CC not responded to increased [ CO2]. • As a physiological mechanism affecting growth, altered energetic properties could positively influence productivity of X. strumarium, and potentially other species, at elevated [ CO2].