Gas exchange and photosynthetic performance of the tropical tree Acacia nigrescens when grown in different CO2 concentrations

Abstract

The photosynthetic responses of the tropical tree species Acacia nigrescens Oliv. grown at different atmospheric CO(2) concentrations-from sub-ambient to super-ambient-have been studied. Light-saturated rates of net photosynthesis (A (sat)) in A. nigrescens, measured after 120 days exposure, increased significantly from sub-ambient (196 microL L(-1)) to current ambient (386 microL L(-1)) CO(2) growth conditions but did not increase any further as [CO(2)] became super-ambient (597 microL L(-1)). Examination of photosynthetic CO(2) response curves, leaf nitrogen content, and leaf thickness showed that this acclimation was most likely caused by reduction in Rubisco activity and a shift towards ribulose-1,5-bisphosphate regeneration-limited photosynthesis, but not a consequence of changes in mesophyll conductance. Also, measurements of the maximum efficiency of PSII and the carotenoid to chlorophyll ratio of leaves indicated that it was unlikely that the pattern of A (sat) seen was a consequence of growth [CO(2)] induced stress. Many of the photosynthetic responses examined were not linear with respect to the concentration of CO(2) but could be explained by current models of photosynthesis.

Sustained Photosynthetic Performance of Coffea spp. under Long-Term Enhanced [CO2]

“…These results agree with those of few studies that have reported invariant responses of g s to elevated [CO 2 ] in woody species [8,55,56]. Indeed, g s has been systematically, but not universally, demonstrated to decrease when plants are grown under elevated [CO 2 ] [8,16,17,22], although such decreases have been shown to occur to a lesser extent in shrubs and trees than in herbaceous annuals [8]. …”

“…Because increasing atmospheric [CO 2 ] enlarges the gradient that ensures adequate diffusion of CO 2 from the atmosphere to the chloroplasts, a rise in [CO 2 ] should produce greater P n coupled with lower T r , which would ultimately improve the water-use efficiency (WUE) in a large number of plant species [8,14,16]. Furthermore, decreases in stomatal opening, stomatal density (SD) and stomatal index (SI), all of which contributing to a reduction in g s , have been reported when plants are grown in elevated [CO 2 ] [8,17-19], although in some cases g s and not SD determines the long-term reduction in leaf T r [20]. Nonetheless, the anticipated stomatal closure that is usually observed at elevated [CO 2 ] will inevitably be associated with lower latent heat loss, thereby increasing leaf temperatures [2].…”

Determination of photosynthetic parameters Vcmax and Jmax for a C3 plant (spring hulless barley) at two altitudes on the Tibetan Plateau

“…For example, Vc max for plants grown at a higher CO 2 partial pressure was lower than for those at a lower CO 2 partial pressure, and both Vc max and J max were lower for cool-climate plants grown at a warmer temperature. Similar research was conducted on other plants (Hikosaka et al, 2006;Possell and Hewitt, 2009), and these conclusions were verified and compared. Notably, although the changes were general, the trend in and extent of change in Vc max and J max were significantly different among plant species.…”

“…The differences might be closely related to the highly diverse environmental conditions in which plants grown. CO 2 and temperature are considered two of the primary environmental factors that determine, directly or indirectly, the photosynthetic capacity (Bunce, 2008;Stojanovic, 2008;Kositsup et al, 2009;Possell and Hewitt, 2009). Changes in CO 2 and temperature affect the photosynthetic capacity at the levels of leaf biochemistry, stomata and CO 2 diffusion as well as photosynthetic component activities and CO 2 partial pressure at the carboxylation sites.…”

The impact of local surface changes in Borneo on atmospheric composition at wider spatial scales: coastal processes, land-use change and air quality

“…There is a well-known dependence on light and temperature, higher temperatures producing higher emissions up to a maximum at approximately 408C [12,13]. Recently, a dependence on CO 2 concentrations has also been shown [54,55], in this case producing a decrease in emissions for CO 2 levels above today's ambient value (approx. 385 ppmv).…”