Plant reproduction under elevated CO₂ conditions: a meta‐analysis of reports on 79 crop and wild species

Abstract

Summary• Reproductive traits are key characteristics for predicting the response of communities and ecosystems to global change.• We used meta-analysis to integrate data on eight reproductive traits from 159 CO 2 enrichment papers that provided information on 79 species.• Across all species, CO 2 enrichment (500 -800 µl l − 1 ) resulted in more flowers (+19%), more fruits (+18%), more seeds (+16%), greater individual seed mass (+4%), greater total seed mass (+25%), and lower seed nitrogen concentration, (N) ( − 14%). Crops and undomesticated (wild) species did not differ in total mass response to elevated CO 2 (+31%), but crops allocated more mass to reproduction and produced more fruits (+28% vs +4%) and seeds (+21% vs +4%) than did wild species when grown at high CO 2 . Seed [N] was not affected by high CO 2 concentrations in legumes, but declined significantly in most nonlegumes.• Our results provide robust estimates of average plant reproductive responses to CO 2 enrichment and demonstrate important differences among individual taxa and among functional groups. In particular, crops were more responsive to elevated CO 2 than were wild species. These differences and the substantial decline in seed [N] in many species have broad implications for the functioning of future natural and agroecosystems.© New Phytologist (2002) 156 : 9 -26

Ecosystem response to elevated CO2 levels limited by nitrogen-induced plant species shift

“…Overall, we found that the observed shift in the plant community composition ultimately suppresses the CO 2 -stimulation of plant productivity by the third and fourth years. Although extensive research has shown that global change factors such as elevated CO 2 concentrations and N pollution affect plant species differently [11][12][13], and that they may drive plant community changes [14][15][16][17] , we demonstrate that plant community shifts can act as a feedback effect that alters the whole ecosystem response to elevated CO 2 concentrations. Moreover, we suggest that trade-offs between the abilities of plant taxa to respond positively to different perturbations may constrain natural ecosystem response to global change.…”

“…Meta-analytic studies suggest that grasses (either including or excluding C 4 grasses) tend to respond strongly to N but poorly to CO 2 ; legumes respond strongly to CO 2 but poorly to N; and trees respond intermediately to both [11][12][13] . Similarly, limited data from individual ecosystems suggest that plant functional group CO 2 responses relate negatively to N responses.…”

Competition and stoichiometry: coexistence of two predators on one prey

“…For example, it is well established that elevated carbon dioxide ðCO 2 Þ; on average, lowers N:C ratio in plants (Cotrufo et al, 1998;Jablonski et al, 2002). It has recently been shown that elevated CO 2 ; similarly to increased light intensity, can decrease P:C ratio in algae (Urabe et al, 2003) and can also alter concentrations of other vital macro-and micro-elements in wild and cultivated plants (Loladze, 2002).…”

Will Elevated Carbon Dioxide Concentration Amplify the Benefits of Nitrogen Fixation in Legumes?

“…Will elevated [CO 2 ] affect legume seed quality to a similar extent? The evidence reported in two meta-analyses suggests that seed protein and N content will not be as affected by elevated [CO 2 ] in legumes as nonlegumes (Jablonski et al, 2002;Taub et al, 2008; Fig. 3).…”

“…In soybean, growth at elevated [CO 2 ] significantly decreased protein content, but only by 1.4% (Taub et al, 2008). Averaging the effects of elevated [CO 2 ] on wild and domestic legumes, there was no effect on seed N (Jablonski et al, 2002). Other important aspects of seed quality are also maintained at elevated [CO 2 ] in legumes.…”