title: A chlorophyll fluorescence analysis of photosynthetic efficiency, quantum yield and photon energy dissipation in PSII antennae of Lactuca sativa L. leaves exposed to cinnamic acid.
abstract: This study investigated the effects of cinnamic acid (CA) on growth, biochemical and physiological responses of Lactuca sativa L. CA (0.1, 0.5, 1.0 and 1.5 mM) treatments decreased plant height, root length, leaf and root fresh weight, but it did not affect the leaf water status. CA treatment (1.5 mM) significantly reduced F(v), F(m), photochemical efficiency of PSII (F(v)/F(m)) and quantum yield of PSII (ΦPSII) photochemistry in L. sativa. The photochemical fluorescence quenching (qP) and non-photochemical quenching (NPQ) were reduced after treatment with 1.5 mM CA. Fraction of photon energy absorbed by PS II antennae trapped by "open" PS II reaction centers (P) was reduced by CA (1.5 mM) while, portion of absorbed photon energy thermally dissipated (D) and photon energy absorbed by PSII antennae and trapped by "closed" PSII reaction centers (E) was increased. Carbon isotope composition ratios (δ(13)C) was less negative (-27.10) in CA (1.5 mM) treated plants as compared to control (-27.61). Carbon isotope discrimination (Δ(13)C) and ratio of intercellular CO(2) concentration (ci/ca) from leaf to air were also less in CA treated plants. CA (1.5 mM) also decreased the leaf protein contents of L. sativa as compared to control.
authors: Department of Plant Biology and Soil Science, University of Vigo, Campus Lagoas-Marcosende, 36310 Vigo, Spain. mih76@uvigo.es
authors: M Iftikhar
authors: MI
authors: Hussain
authors: Manuel J
authors: MJ
authors: Reigosa
mesh_terms: D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism*; D002247:Carbon Isotopes / Q000032:analysis; D002734:Chlorophyll / Q000378:metabolism; D002934:Cinnamates / Q000494:pharmacology*; D005453:Fluorescence; D018545:Lactuca / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D008027:Light; D010777:Photochemistry; D017785:Photons; D010788:Photosynthesis / Q000187:drug effects*; D045332:Photosystem II Protein Complex / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D010940:Plant Proteins / Q000032:analysis; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D014867:Water / Q000378:metabolism
chemical_list: D002247:Carbon Isotopes; D002934:Cinnamates; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D014867:Water; C029010:cinnamic acid; D002734:Chlorophyll; D002245:Carbon Dioxide