title: Mechanism of lanthanum effect on chlorophyll of spinach.
abstract: The mechanism of La(3+) effect on chlorophyll (chl) of spinach in solution culture has been studied. The results show that La(3+) can obviously promote growth, increase chlorophyll contents and photosynthetic rate of spinach. La(3+) may substitute Mg(2+) for chlorophyll formation of spinach when there is no Mg(2+) in solution. La(3+) improves significantly PSII formation and enhances electron transport rate of PSII. By ICP-MS and atom absorption spectroscopy methods, it has been revealed that rare earth elements (REEs) can enter chloroplasts and increase Mg(2+)-chl contents; and REEs bind to chlorophyll and also form REE-chl. REE-chl is about 72% in total chlorophyll with La(3+) treatment and without Mg(2+)in solution. By UV-Vis, FT-IR and extended X-ray absorption fine structure spectroscopy (EXAFS) methods, it has been found that La(3+) coordinates with nitrogen of porphyrin rings with the average La-N bond length of 0.253 nm.
authors.affiliation: Department of Biology, Life Sciences College, Suzhou University, 215151, Suzhou, China, hongfsh_cn@sina.com.
authors.forename: Fashui
authors.initials: F
authors.lastname: Hong
authors.forename: Zhenggui
authors.initials: Z
authors.lastname: Wei
authors.forename: Guiwen
authors.initials: G
authors.lastname: Zhao