Coupling of respiration, nitrogen, and sugars underlies convergent temperature acclimation in Pinus banksiana across wide‐ranging sites and populations

Abstract

Patterns and mechanisms of short-term temperature acclimation and long-term climatic adaptation of respiration among intraspecific populations are poorly understood, but both are potentially important in constraining respiratory carbon flux to climate warming across large geographic scales, as well as influencing the metabolic fitness of populations. Herein we report on leaf dark respiration of 33-year-old trees of jack pine (Pinus banksiana Lamb.) grown in three contrasting North American common gardens (0.9, 4.6, and 7.9 1C, mean annual temperature) comprised of identical populations of wideranging geographic origins. We tested whether respiration rates in this evergreen conifer acclimate to prevailing ambient air temperatures and differ among populations. At each of the common gardens, observed population differences in respiration rates measured at a standard temperature (20 1C) were comparatively small and largely unrelated to climate of seed-source origin. In contrast, respiration in all populations exhibited seasonal acclimation at all sites. Specific respiration rates at 20 1C inversely tracked seasonal variation in ambient air temperature, increasing with cooler temperatures in fall and declining with warmer temperatures in spring and summer. Such responses were similar among populations and sites, thus providing a general predictive equation regarding temperature acclimation of respiration for the species. Temperature acclimation was associated with variation in nitrogen (N) and soluble carbohydrate concentrations, supporting a joint enzyme and substrate-based model of respiratory acclimation. Regression analyses revealed convergent relationships between respiration and the combination of needle N and soluble carbohydrate concentrations and between N-based respiration (R N , lmol mol N À1 s À1 ) and soluble carbohydrate concentrations, providing evidence for general predictive relationships across geographically diverse populations, seasons, and sites. Overall, these findings demonstrate that seasonal acclimation of respiration modulates rates of foliar respiratory carbon flux in a widely distributed evergreen species, and does so in a predictable way. Genetic differences in specific respiration rate appear less important than temperature acclimation in downregulating respiratory carbon fluxes with climate warming across wide-ranging sites.

Thermal optimality of net ecosystem exchange of carbon dioxide and underlying mechanisms

“…Previous studies have shown that plant photosynthesis and GPP can acclimate to temperature change via an increase in optimum temperature in a warmer environment (Mooney et al, 1978;Baldocchi et al, 2001;Niu et al, 2008). It has also been documented that R e responds exponentially to temperature as long as there is no soil water limitation (Law et al, 1999), and its temperature sensitivity (Q 10 ) decreases in a warmer environment, a process also described as temperature acclimation (Lloyd & Taylor, 1994;Luo et al, 2001;Tjoelker et al, 2008;Piao et al, 2010). The temperature acclimation of either GPP or R e can lead to changes in the temperature response of NEP.…”

Metabolism and Growth in Arabidopsis Depend on the Daytime Temperature but Are Temperature-Compensated against Cool Nights

“…Like photosynthesis, respiratory acclimation is more marked in leaves that develop at the new temperature (Campbell et al, 2007). Several factors contribute, including the general increase in protein content (Atkin et al, 2005(Atkin et al, , 2008Campbell et al, 2007;Tjoelker et al, 2008) and changes in the activities or levels of specific respiratory enzymes, in particular alternative oxidase and uncoupling protein (Armstrong et al, 2007;Campbell et al, 2007). Respiration is often subdivided into growth respiration (R g ) and maintenance respiration (R m ; Penning de Vries et al, 1974;Amthor, 2000).…”

Evidence for a weakening relationship between interannual temperature variability and northern vegetation activity

“…The effect of climate drought on the temperature sensitivity of vegetation growth, however, may be partly alleviated by CO 2 -induced increase in vegetation water use efficiency 11,12 . In addition, some species can also gradually adjust to continuous warming by acclimation of their physiological responses (for example, through their rates of photosynthesis and autotrophic respiration) [13][14][15] . These issues all lead to the question of how and where has the impact of temperature on vegetation productivity changed over the last three decades?…”