title: The effects of lead stress on photosynthetic function and chloroplast ultrastructure of Robinia pseudoacacia seedlings.
abstract: In this experiment, the effects of different lead (Pb) concentrations (0, 200, 600, 1000, 1400 mg kg-1) on photosynthesis and chlorophyll fluorescence in Robinia pseudoacacia seedlings were examined. As Pb concentration increased, chlorophyll a, chlorophyll b, total chlorophyll content, net photosynthetic rate, transpiration rate, stomatal conductance (gs), and mesophyll intercellular carbon dioxide concentration were gradually reduced. Maximal photochemical efficiency, photochemical quenching, and quantum yield also decreased. However, the initial fluorescence and nonphotochemical quenching gradually increased. Chloroplasts swelled owing to local plasmolysis and lost most of their starch content, and their thylakoid lamellae gradually became disordered and loosely packed. When the chloroplast envelope was lost under high Pb stress (≥1000 mg kg-1), lipid globules were released into the surrounding mesophyll cell. Multiple regression analysis showed that gsand inactivity of the PSII reaction center had the greatest effect on photosynthetic function, whereas inhibition of electron transport had minimal effects on black locust seedlings under Pb stress.
authors.affiliation: School of Horticulture and Landscape Architecture, Institute of Science and Technology of Henan, Xinxiang, Henan, 453003, China.|Research Institute of Forestry Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhou
authors.affiliation: Research Institute of Forestry Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Zeping
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: School of Horticulture and Landscape Architecture, Institute of Science and Technology of Henan, Xinxiang, Henan, 453003, China.|Research Institute of Forestry Chinese Academy of Forestry, Beijing, 100091, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.affiliation: School of Horticulture and Landscape Architecture, Institute of Science and Technology of Henan, Xinxiang, Henan, 453003, China.
authors.forename: Lifeng
authors.initials: L
authors.lastname: Yang
authors.affiliation: Research Institute of Forestry Chinese Academy of Forestry, Beijing, 100091, China. m13525059684@163.com.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wei
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D002736:Chloroplasts / Q000378:metabolism; D005453:Fluorescence; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000378:metabolism; D031301:Robinia; D036226:Seedlings / Q000187:drug effects*
chemical_list: D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A
keywords: Character; Chlorophyll; Fluorescence; Lead stress; Photosynthesis; Ultrastructure