A meta-analysis of plant physiological and growth responses to temperature and elevated CO2

Abstract

Atmospheric carbon dioxide (CO(2)) and global mean temperature are expected to be significantly higher by the end of the 21st century. Elevated CO(2) (eCO(2)) and higher temperature each affect plant physiology and growth, but their interactive effects have not been reviewed statistically with respect to higher chronic mean temperatures and abrupt heat stress. In this meta-analysis, we examined the effect of CO(2) on the physiology and growth of plants subjected to different temperature treatments. The CO(2) treatments were categorized into ambient (<400 ppm) or elevated (>560 ppm) levels, while temperature treatments were categorized into ambient temperature (AT), elevated temperature (ET; AT + 1.4-6°C), or heat stress (HS; AT + >8°C). Plant species were grouped according to photosynthetic pathways (C(3), C(4)), functional types (legumes, non-legumes), growth forms (herbaceous, woody), and economic purposes (crop, non-crop). eCO(2) enhanced net photosynthesis at AT, ET, and HS in C(3) species (especially at the HS level), but in C(4) species, it had no effect at AT, a positive effect at ET, and a negative effect at HS. The positive effect of eCO(2) on net photosynthesis was greater for legumes than for non-legumes at HS, for non-crops than crops at ET, and for woody than herbaceous species at ET and HS. Total (W (T)) and above- (W (AG)) and below-ground (W (BG)) biomass were increased by eCO(2) for most species groups at all temperatures, except for C(4) species and W (BG) of legumes at HS. Hence, eCO(2) × heat effects on growth were often not explained by effects on net photosynthesis. Overall, the results show that eCO(2) effects on plant physiology and growth vary under different temperature regimes, among functional groups and photosynthetic pathways, and among response variables. These findings have important implications for biomass accumulation and ecosystem functioning in the future when the CO(2) level is higher and climate extremes, such as heat waves, become more frequent.

Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of soybean (Glycine max) at elevated [CO2] and temperatures under fully open air field conditions

“…Increased access to moisture in 2009 and warmer temperature in the HOT plots would likely increase the nitrogen nutrition of plants whereas nitrogen nutrition in soybeans was inhibited in drought [53] potentially explaining why N area was higher in HOT plots compared to control plots in 2009 and why in 2011 N levels were generally lower than at comparable developmental stages in 2009. Thus, when leaf N was higher in HOT plots and in the absence of water stress, elevated temperature and [CO 2 ] increased carboxylation capacity relative to elevated [CO 2 ] alone which is consistent with a recent metaanalysis of plant responses to elevated [CO 2 ] and temperature [7] and mirrors nodulating Medicago trunculata grown in temperature gradient tunnels (+4 • C) at ambient and elevated (700 ppm) CO 2 [54].…”

“…The coupled impact of these changes on carbon assimilation and photosynthetic acclimation in the field is highly uncertain because experiments examining the combined effects of elevated [CO 2 ] and temperature have been largely restricted to enclosed chambers [3,4], open top chambers [5] and gradient tunnels [6]. Moreover, the realized benefit of the combined effect of elevated [CO 2 ] and temperature on carbon assimilation differs depending on the type of enclosure, as well as the species and the functional types examined as they acclimate in different ways [7]. Taken together, these observations underscore the importance of evaluating and analyzing plant responses to future [CO 2 ] and elevated temperature under field conditions.…”

The Responses of Plant Leaf CO2/H2O Exchange and Water Use Efficiency to Drought: A Meta-Analysis

“…In recent years, a number of publications have focused on meta-analysis of plants under stress conditions; this study method is favored because it summarizes and integrates the results from numerous independent experiments while accounting for variability across experiments [28,29]. Meta-analyses have been used to study the responses of plant physiological traits [30] and grain yield [31,32] to drought conditions; and the method has been used to study the responses of plant leaf gas exchange and growth under elevated CO 2 and temperature [33,34]. Researchers have used meta-analysis to explore the central tendency and identify different patterns of leaf gas exchange and water status responses to drought under different moderators (e.g., drought intensity, metabolic CO 2 assimilation, and growth forms) [30].…”

Identifying the future water and salinity risks to irrigated viticulture in the Murray-Darling Basin, South Australia

“…A rise in temperatures, for instance, could lead to soil moisture deficits and a growing risk of vegetation desiccation due to increased evapotranspiration and decreased soil moisture (Goyal, 2004;Riediger et al, 2014). On the other hand, increased CO 2 concentrations in the atmosphere may provide an enhanced opportunity for higher carbon assimilation by crops and lead to an increase in the crop yield (Wang et al, 2012), provided that other inputs are not limiting the crop growth. Ecological and economic consequences of climate change on agricultural ecosystems are expected to vary widely depending on the spatial patterns of land cover, land use practices, and regional climate variability (Bindi and Olesen, 2011;Australia has the largest area under arid and semi-arid climate in the world, with about 80% of the country receiving rainfall of less than 600 mm per year (Mushtaq et al, 2013).…”