
TY  - JOUR
A1  - Siebke, Katharina 
A1  - Ghannoum, Oula 
A1  - Conroy, Jann P. 
A1  - Caemmerer, Susanne von 
T1  - Elevated CO<emph type="8">2</emph> increases the leaf temperature of two glasshouse-grown C<emph type="8">4</emph> grasses
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2002
VL  - 29
IS  - 12
SP  - 1377
EP  - 1385
KW  - C4 grasses, C4 photosynthesis, elevated CO2, leaf temperature, stomatal conductance.
UR  - https://doi.org/10.1071/FP02075 
N2  - This study investigates the effect of elevated CO2 partial pressure (pCO2)-induced stomatal closure on leaf temperature and gas exchange of C4 grasses. Two native Australian C4 grasses, Astrebla lappacea (Lindl.) Domin and Bothriochloa bladhii Kuntze, were grown at three different pCO2 (35, 70 and 120 Pa) in three matched, temperature-controlled glasshouse compartments. The difference between leaf and air temperature (&#916;T) was monitored diurnally with thermocouples. &#916;T increased with both step-increases of ambient pCO2. Average noon leaf temperature increased by 0.4 and 0.3&#176;C for A. lappacea with the 35&#8211;70 and 70&#8211;120 Pa steps of pCO2 elevation, respectively. For B. bladhii, the increases were 0.5&#176;C for both pCO2 steps. &#916;T was strongly dependent on irradiance, pCO2 and air humidity. Leaf gas exchange was measured at constant temperature and high irradiance at the three growth pCO2. Under these conditions, CO2 assimilation saturated at 70 Pa, while stomatal conductance decreased by the same extent (0.58-fold) with both step-increases in pCO2, suggesting that whole-plant water use efficiency of C4 grasses would increase beyond a doubling of ambient pCO2. The ratio of intercellular to ambient pCO2 was not affected by short- or long-term doubling or near-tripling of pCO2, in either C4 species when measured under standard conditions. 
ER  -

