title: Excess iron-induced changes in the photosynthetic characteristics of sweet potato.
abstract: Iron (Fe) is an essential nutrient for plant growth and development. In plant tissues, approximately 80% of Fe is found in photosynthetic cells. This study was carried out to determine the effect of different iron concentrations on the photosynthetic characteristics of sweet potato plants. The fluorescence transient of chlorophyll a (OJIP), chlorophyll index and gas exchange were measured in plants grown for seven days in Hoagland solution containing an iron concentration of 0.45, 0.90, 4.50 or 9.00 mM Fe (as Fe-EDTA). The initial and maximum fluorescence increased in the plants receiving 9.00 mM Fe. In the analysis of the fluorescence kinetic difference, L- and K-bands appeared in all of the treatments, but the amplitude was higher in plants receiving 4.50 or 9.00 mM Fe. In plants grown in 9.00 mM Fe, the parameters of the JIP-Test indicated a better efficiency in the capture, absorption and use of light energy, and although the chlorophyll index was higher, the net photosynthesis was lower. The overall data showed that sweet potato plants subjected to high iron concentrations may not exhibit the toxicity symptoms, but the light reactions of photosynthesis can be affect, which may result in a declining net assimilation rate.
authors.affiliation: Laboratório de Cultura de Células e Tecidos Vegetais, UFPel, Instituto de Biologia, Depto. Botânica, Campus Universitário S/N., CEP 96160-000, Capão do Leão, RS, Brazil.
authors.forename: Janete M
authors.initials: JM
authors.lastname: Adamski
authors.forename: José A
authors.initials: JA
authors.lastname: Peters
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Danieloski
authors.forename: Marcos A
authors.initials: MA
authors.lastname: Bacarin
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D005453:Fluorescence; D018527:Hydroponics; D027723:Ipomoea batatas / Q000187:drug effects* / Q000502:physiology; D007501:Iron / Q000494:pharmacology*; D010788:Photosynthesis / Q000187:drug effects*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D018520:Plant Shoots / Q000187:drug effects / Q000502:physiology; D018526:Plant Transpiration / Q000187:drug effects
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D007501:Iron; D000077194:Chlorophyll A