Methane emissions from six crop species exposed to three components of global climate change: temperature, ultraviolet-B radiation and water stress

• Published in: Physiologia plantarum Vol. 137; no. 2; pp. 139 - 147
• Main Authors: Qaderi, Mirwais M, Reid, David M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.10.2009; Blackwell Publishing Ltd; Blackwell
• Subjects: air temperature; barley; beans; Biological and medical sciences; Biomass; Brassica napus; canola; carbon dioxide; Carbon Dioxide - metabolism; climate change; crops; Crops, Agricultural - growth & development; Crops, Agricultural - metabolism; Crops, Agricultural - radiation effects; Dehydration; detectors; Fundamental and applied biological sciences. Psychology; gas chromatography; gas emissions; gas exchange; greenhouse effect; growth chambers; Helianthus; Helianthus annuus; Hordeum vulgare; ionization; leaf area; leaves; methane; Methane - metabolism; peas; Pisum sativum; plant growth; Plant Leaves - growth & development; Plant Leaves - metabolism; Plant Leaves - radiation effects; Plant physiology and development; stems; Temperature; transpiration; Triticum aestivum; ultraviolet radiation; Ultraviolet Rays; Vicia faba; water stress; water use efficiency; wheat; Dynamical climatology; Methane; Climate change; Temperature; Gas emission; Plant physiology; UVB radiation; Global change; Cultivated plant; Species; Water stress
• DOI: 10.1111/j.1399-3054.2009.01268.x
• ISSN: 0031-9317

We examined the effects of temperature, ultraviolet-B (UVB) radiation and watering regime on aerobic methane (CH₄) emission from six crops-faba bean, sunflower, pea, canola, barley and wheat. Plants were grown in controlled-environment growth chambers under two temperature regimes (24/20 and 30/26°C), three levels of UVB radiation [0 (zero), 5 (ambient) and 10 (enhanced) kJ m⁻² d⁻¹] and two watering regimes (well watered and water stressed). A gas chromatograph with a flame ionization detector was used to measure CH₄ emission rates [ng g⁻¹ dry weight (DW) h⁻¹] from detached fresh leaves of each species and attached leaves of pea plants. Plant growth [stem height, leaf area (LA) and aboveground dry matter (AG biomass)] and gas exchange [net CO₂ assimilation (AN), transpiration (E) and water use efficiency (WUE)] were also determined. We found that higher temperature, water stress and UVB radiation at the zero and enhanced levels significantly enhanced CH₄ emissions. Crop species varied in CH₄ emission, which was highest for pea and lowest for barley. Higher temperature and water stress reduced all growth parameters, whereas ambient and enhanced UVB decreased stem height but increased LA and AG biomass. Higher temperature decreased AN and WUE but increased E, whereas water stress decreased AN but increased E and WUE. Zero and enhanced UVB reduced AN and E. Growth and gas exchange varied with species. Overall, CH₄ emission was negatively correlated with stem height and AG biomass. We conclude that CH₄ emissions may increase under climatic stress conditions and this extra source might contribute to the 'greenhouse effect'.