This study compared the leaf transcription profiles, physiological characteristics and primary metabolites of two Populus tremuloides genotypes (clones 216 and 271) known to differ in their responses to long-term elevated [CO2] (e[CO2]) at the Aspen free-air CO2 enrichment site near Rhinelander, WI, USA. The physiological responses of these clones were similar in terms of photosynthesis, stomat...

Crassulacean acid metabolism (CAM) is an important elaboration of photosynthetic carbon fixation that allows chloroplast-containing cells to fix CO2 initially at night using phosphoenolpyruvate carboxylase (PEPC) in the cytosol. This leads to the formation of C4 organic acids (usually malate), which are stored in the vacuole. Subsequent daytime decarboxylation of these organic acids behind clos...

Leaf-level measurements have shown that mesophyll conductance (gm) can vary rapidly in response to CO2 and other environmental factors, but similar studies at the canopyscale are missing. Here, we report the effect of short-term variation of CO2 concentration on canopy-scale gm and other CO2 exchange parameters of sunflower (Helianthus annuus L.) stands in the presence and absence of abscisic a...

Cuticular properties affect the gas exchange of leaves, but little is known about how much CO2 and water vapor cross the cuticular barrier or whether low water potentials affect the process. Therefore, we measured the cuticular conductances for CO2 and water vapor in grape (Vitis vinifera L.) leaves having various water potentials. The lower leaf surface was sealed to force all gas exchange thr...

Crassulacean acid metabolism (CAM) is a major physiological syndrome that has evolved independently in numerous land plant lineages. CAM plants are of great ecological significance, and there is increasing interest for their water-use efficiency and drought resistance. Integral to the improvement in water-use efficiency that CAM affords is a unique pattern of stomatal conductance, distinguished...

Plant height, biomass production, assimilatory functions and chlorophyll accumulation of Panicum maximum and Stylosanthes hamata in intercropping systems was influenced significantly under elevated CO2 (600 +/- 50 ppm) in open top chambers (OTCs). The plant height increased by 32.0 and 49.0% over the control in P. maximum and S. hamata respectively in intercropping system under elevated CO2 ove...

The expression and activity of glutamine synthetase (GS, EC 6.3.1.2) were examined in relation to the rate of CO2 assimilation in sunflower (Helianthus annuus L.) leaves. Intact plants were kept in the dark for 72 h and subsequently exposed to light under different atmospheric CO2 concentrations (100, 400 and 1200 microl l-1) for 6 h. The in vivo rates of net CO2 assimilation correlated with at...

The expression and activity of glutamine synthetase (GS, EC 6.3.1.2) were examined in relation to the rate of CO2 assimilation in sun ̄ower (Helianthus annuus L.) leaves. Intact plants were kept in the dark for 72 h and subsequently exposed to light under different atmospheric CO2 concentrations (100, 400 and 1200 ml l) for 6 h. The in vivo rates of net CO2 assimilation correlated with atmospher...