Table 3. Comparison of the experimental setup and parameters in Funck et al. [5] and our study.

Parameter	Funck et al. 2008	This study
δOAT expression	Knockout	Gene induced under light
Gowth conditions	MS medium, 110 μE, 9 h light, 22°C	Soil, 150 μE, 8 h light/ 16 h dark, 22°C/20°C; MS medium, 150 μE, 8 h light/ 16 h dark, 22°C/20°C
CO2 supply	Ambient	Low (100 ppm)
N-supply	5 mM arginine + 0.5 mM glutamine; 10 mM ornithine + 0.5 mM glutamine	High due to increased photorespiration
Urea cycle intermediates	Accumulation in oat mutants under the N-supply given above; arginine and ornithine cannot be used as a sole nitrogen source in the absence of glutamine; urea can be metabolized without any difficulty	Accumulation under low CO2 conditions; alternative sink of nitrogen produced by photorespiration?
Proposed/possible function of δOAT	Essential exit rout of nitrogen from urea cycle under physiological conditions	Possible function in glutamate homeostasis and/or production of glutamate for photorespiration