Introduction to a Virtual Special Issue on plant respiration in variable environments

Link to the Virtual Special Issue *New Phytologist* has a long history in publishing studies that enhance our understanding of the underlying mechanisms that regulate plant respiratory metabolism, and how environmental gradients impact on respiratory rates. For example, over 100 yr ago, reference was made to the work of Müller-Thurgau on responses of potato tuber respiration to temperature (Arber, 1910), where it was stated: ‘The respiration is intimately connected throughout with the supply of sugar which is available. It is very high in potatoes which have been kept at 0 ° and have become sweet: at ordinary temperatures, it is low in the autumn when little or no sugar is present and increases with the accumulation of sugar as the tubers grow older.’ Thus, even at that early stage of ‘modern’ plant physiology research, insights were being made into how respiration acclimates to sustained changes in growth temperature and environment-mediated changes in carbon supply. Similarly, *New Phytologist* published early seminal work on temperature responses of respiration in Arctic plants (Wager, 1941), underlying factors regulating respiratory flux (James & Arney, 1939; Wohl & James, 1942), and linkages between thermogenesis and cyanide-resistant respiration (James & Beevers, 1950). Thereafter, an increasing number of respiration-focused papers were published during the period 1960–2010. Here, we build on this rich heritage of past respiration-related research by highlighting in a *Virtual Special Issue* (*VSI*, http://bit.ly/NewPhytVirtualIssue) recent papers from *New Phytologist* that further enhance our understanding of: respiration–temperature interactions, both in nonthermogenic and thermogenic tissues; how leaf respiratory metabolism differs in the light and darkness; the importance of respiration for the carbon economy of individual plants and whole ecosystems; sources of carbon used in above- and below-ground respiratory metabolism; and factors regulating respiratory metabolism in plants. Collectively, the assembled papers provide important insights into a vital metabolic process that is crucial to the functioning of individual plants (Penning de Vries, 1975; Lambers, 1985; Krömer, 1995; Raghavendra & Padmasree, 2003) and ecosystems (Atkin et al., 2008; Metcalfe et al., 2010), and the extent to which atmospheric CO2 will be sequestered by the terrestrial biosphere (King et al., 2006). (No Background, Methods, Results, or Conclusions headings present in the published abstract.)