Individual and interactive effects of temperature and light intensity on canola growth, physiological characteristics and methane emissions

• Published in: Plant physiology and biochemistry Vol. 157; pp. 160 - 168
• Main Authors: Martel, Ashley B., Taylor, Amanda E., Qaderi, Mirwais M.
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.12.2020
• Subjects: Amino acid; Brassica napus; Brassica napus - growth & development; Brassica napus - metabolism; Brassica napus - radiation effects; Canola; Ethylene; Light; Light intensity; Methane - metabolism; Methane emission; Temperature; Methane emission; Temperature; Amino acid; Ethylene; Brassica napus; Light intensity; Canola
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2020.10.016

Earlier studies have shown that plants produce methane (CH4) under aerobic conditions, and that this emission is not microbial in nature. However, the precursors of aerobic CH4 remain under debate, and the combined effects of environmental factors on plant-derived CH4 requires further attention. The objective of this study was to determine the interactive effects of temperature and light intensity on CH4 and other relevant plant parameters in canola (Brassica napus L.). Plants were grown under two temperature regimes (22/18 °C and 28/24 °C, 16 h light/8 h dark) and two light intensities (300 and 600 μmol photons m−2 s−1) for 21 days after one week of growth under 22/18 °C (16 h light/8 h dark). In this study, higher temperature had little effects on CH4 emissions from plants, indicating the mitigating effects of higher light intensity. Higher light intensity, however, significantly decreased CH4, which was inversely related to plant dry mass. Higher light intensity decreased stem height, leaf area ratio, chlorophyll, nitrogen balance index, leaf moisture, methionine (Met) and ethylene (C2H4), but increased specific leaf mass, photochemical quenching, flavonoids, epicuticular wax, lysine and tyrosine. The results revealed that increased CH4 emissions from plants could be related to changes in plant physiological activities, which portrayed themselves in increased C2H4 evolution, and methylated amino acids, such as Met. We conclude that higher light intensity reduces Met and, in turn, CH4 and C2H4 emissions, but lower light intensity enhances CH4 formation through cleavage of methyl group of amino acids by reactive oxygen species, as previously suggested. •Environmental stressors adversely affect plant growth and physiological processes.•Higher light intensity decreases plant methionine and methane emissions.•Plant-derived methane is inversely related to plant dry mass.•It is important to understand methane precursors and their regulating factors.