TY - JOUR
T1 - Ammonia emission from rice leaves in relation to photorespiration and genotypic differences in glutamine synthetase activity
AU - Kumagai, Etsushi
AU - Araki, Takuya
AU - Hamaoka, Norimitsu
AU - Ueno, Osamu
N1 - Funding Information:
This study was supported by a grant from the Japanese Society for the Promotion of Science Research Fellowship for Young Scientists to E.K. (No. 08J03273). We thank Mr Masayuki Tsuji, Department of Technology Education, Fukuoka University of Education, for his help in the manufacture of the assimilation chamber. We are greatly indebted to Dr David Lawlor and anonymous reviewers for invaluable comments and suggestions.
PY - 2011/11
Y1 - 2011/11
N2 - Background and Aims: Rice (Oryza sativa) plants lose significant amounts of volatile NH3 from their leaves, but it has not been shown that this is a consequence of photorespiration. Involvement of photorespiration in NH 3 emission and the role of glutamine synthetase (GS) on NH 3 recycling were investigated using two rice cultivars with different GS activities. • Methods: NH 3 emission (AER), and gross photosynthesis (P G), transpiration (T r) and stomatal conductance (g S) were measured on leaves of 'Akenohoshi', a cultivar with high GS activity, and 'Kasalath', a cultivar with low GS activity, under different light intensities (200, 500 and 1000 μmol m -2 s -1), leaf temperatures (27·5, 32·5 and 37·5 °C) and atmospheric O 2 concentrations ([O 2]: 2, 21 and 40%, corresponding to 20, 210 and 400 mmol mol -1). • Key Results: An increase in [O 2] increased AER in the two cultivars, accompanied by a decrease in P G due to enhanced photorespiration, but did not greatly influence Tr and g S. There were significant positive correlations between AER and photorespiration in both cultivars. Increasing light intensity increased AER, P G, Tr and g S in both cultivars, whereas increasing leaf temperature increased AER and Tr but slightly decreased P G and g S. 'Kasalath' (low GS activity) showed higher AER than 'Akenohoshi' (high GS activity) at high light intensity, leaf temperature and [O 2]. • Conclusions: Our results demonstrate that photorespiration is strongly involved in NH 3 emission by rice leaves and suggest that differences in AER between cultivars result from their different GS activities, which would result in different capacities for reassimilation of photorespiratory NH 3. The results also suggest that NH 3 emission in rice leaves is not directly controlled by transpiration and stomatal conductance.
AB - Background and Aims: Rice (Oryza sativa) plants lose significant amounts of volatile NH3 from their leaves, but it has not been shown that this is a consequence of photorespiration. Involvement of photorespiration in NH 3 emission and the role of glutamine synthetase (GS) on NH 3 recycling were investigated using two rice cultivars with different GS activities. • Methods: NH 3 emission (AER), and gross photosynthesis (P G), transpiration (T r) and stomatal conductance (g S) were measured on leaves of 'Akenohoshi', a cultivar with high GS activity, and 'Kasalath', a cultivar with low GS activity, under different light intensities (200, 500 and 1000 μmol m -2 s -1), leaf temperatures (27·5, 32·5 and 37·5 °C) and atmospheric O 2 concentrations ([O 2]: 2, 21 and 40%, corresponding to 20, 210 and 400 mmol mol -1). • Key Results: An increase in [O 2] increased AER in the two cultivars, accompanied by a decrease in P G due to enhanced photorespiration, but did not greatly influence Tr and g S. There were significant positive correlations between AER and photorespiration in both cultivars. Increasing light intensity increased AER, P G, Tr and g S in both cultivars, whereas increasing leaf temperature increased AER and Tr but slightly decreased P G and g S. 'Kasalath' (low GS activity) showed higher AER than 'Akenohoshi' (high GS activity) at high light intensity, leaf temperature and [O 2]. • Conclusions: Our results demonstrate that photorespiration is strongly involved in NH 3 emission by rice leaves and suggest that differences in AER between cultivars result from their different GS activities, which would result in different capacities for reassimilation of photorespiratory NH 3. The results also suggest that NH 3 emission in rice leaves is not directly controlled by transpiration and stomatal conductance.
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U2 - 10.1093/aob/mcr245
DO - 10.1093/aob/mcr245
M3 - Article
C2 - 21937483
AN - SCOPUS:80054895650
SN - 0305-7364
VL - 108
SP - 1381
EP - 1386
JO - Annals of Botany
JF - Annals of Botany
IS - 7
ER -