Down co-regulation of light absorption, photochemistry, and carboxylation in Fe-deficient plants growing in different environments.
The regulation of photosynthesis through changes in light absorption, photochemistry, and carboxylation efficiency has been studied in plants grown in different environments. Iron deficiency was induced in sugar beet (Beta vulgaris L.) by growing plants hydroponically in controlled growth chambers in the absence of Fe in the nutrient solution. Pear (Pyrus communis L.) and peach (Prunus persica L. Batsch) trees were grown in field conditions on calcareous soils, in orchards with Fe deficiency-chlorosis. Gas exchange parameters were measured in situ with actual ambient conditions. Iron deficiency decreased photosynthetic and transpiration rates, instantaneous transpiration efficiencies and stomatal conductances, and increased sub-stomatal CO(2) concentrations in the three species investigated. Photosynthesis versus CO(2) sub-stomatal concentration response curves and chlorophyll fluorescence quenching analysis revealed a non-stomatal limitation of photosynthetic rates under Fe deficiency in the three species investigated. Light absorption, photosystem II, and Rubisco carboxylation efficiencies were down-regulated in response to Fe deficiency in a coordinated manner, optimizing the use of the remaining photosynthetic pigments, electron transport carriers, and Rubisco.
Larbi
Ajmi
A
Department of Plant Nutrition, Aula Dei Experimental Station, Spanish Council for Scientific Research (CSIC), Apdo. 202, Zaragoza, E-50080, Spain.
Abadía
Anunciación
A
Abadía
Javier
J
Morales
Fermín
F
D027461:Beta vulgaris / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D015536:Down-Regulation; D007501:Iron / Q000378:metabolism*; D008027:Light; D010777:Photochemistry; D045332:Photosystem II Protein Complex / Q000737:chemistry / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D018526:Plant Transpiration; D027861:Prunus / Q000378:metabolism*; D031989:Pyrus / Q000378:metabolism*; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism
D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D007501:Iron; D012273:Ribulose-Bisphosphate Carboxylase