title: Absorption and transfer of light and photoreduction activities of spinach chloroplasts under calcium deficiency: promotion by cerium.
abstract: Chloroplasts were isolated from spinach cultured in calcium-deficient, cerium-chloride-administered calcium-present Hoagland's media or that of calcium-deficient Hoagland's media and demonstrated the effects of cerium on distribution of light energy between photosystems II and I and photochemical activities of spinach chloroplast grown in calcium-deficient media. It was observed that calcium deprivation significantly inhibited light absorption, energy transfer from LHCII to photosystemII, excitation energy distribution from PSI to PSII, and transformation from light energy to electron energy and oxygen evolution of chloroplasts. However, cerium treatment to calcium-deficient chloroplasts could obviously improve light absorption and excitation energy distribution from photosystem I to photosystem II and increase activity of whole chain electron transport, photosystems II and I DCPIP photoreduction, and oxygen evolution of chloroplasts. The results suggested that cerium under calcium deficiency condition could substitute for calcium in chloroplasts, maintain the stability of chloroplast membrane, and improve photosynthesis of spinach chloroplast, but the mechanisms still need further study.
authors.affiliation: College of Life Sciences, Suzhou University, Suzhou, 215123, People's Republic of China.
authors.forename: Huang
authors.initials: H
authors.lastname: Hao
authors.forename: Chen
authors.initials: C
authors.lastname: Ling
authors.forename: Liu
authors.initials: L
authors.lastname: Xiaoqing
authors.forename: Liu
authors.initials: L
authors.lastname: Chao
authors.forename: Cao
authors.initials: C
authors.lastname: Weiqian
authors.forename: Lu
authors.initials: L
authors.lastname: Yun
authors.forename: Hong
authors.initials: H
authors.lastname: Fashui
mesh_terms: D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D002563:Cerium / Q000494:pharmacology*; D002736:Chloroplasts / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*; D004579:Electron Transport / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D010101:Oxygen Consumption / Q000187:drug effects / Q000528:radiation effects; D010777:Photochemistry; D010788:Photosynthesis / Q000187:drug effects / Q000528:radiation effects; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D018724:Spinacia oleracea / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D002563:Cerium; D002118:Calcium