title: An alternative strategy of dismantling of the chloroplasts during leaf senescence observed in a high-yield variety of barley.
abstract: Changes in function and composition of the photosynthetic apparatus as well as the ultrastructure of chloroplasts in mesophyll cells were analyzed in flag leaves of the high-yield barley (Hordeum vulgare) variety cv. Lomerit during senescence under field conditions in two successive years. In contrast to previous results obtained with the elder variety cv. Carina photosystem II efficiency measured by F(v)/F(m) was found to be rather stable until a very late stage of senescence. Chlorophyll a fluorescence and P700 absorbance measurements revealed that the activities of the two photosystems declined in parallel. An increase in the chlorophyll a/b ratio at a late stage of senescence was observed to coincide with a decline in the level of the Lhcb1 apoprotein of the light harvesting complex (LHC) and the level of the corresponding transcript. Ultrastructural investigations revealed the presence of gerontoplasts that have long, single or pairwise thylakoids and lack large grana stacks. It is hypothesized that the early degradation of grana thylakoids harboring the major LHC reduced the risk of photoinhibition and might be causally related to the high yield of the barley variety cv. Lomerit.
authors.affiliation: Institute of Botany, Christian-Albrechts-University of Kiel, Kiel, Germany. kkrupinska@bot.uni-kiel.de
authors.forename: Karin
authors.initials: K
authors.lastname: Krupinska
authors.forename: Maria
authors.initials: M
authors.lastname: Mulisch
authors.forename: Julien
authors.initials: J
authors.lastname: Hollmann
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Tokarz
authors.forename: Wiebke
authors.initials: W
authors.lastname: Zschiesche
authors.forename: Henning
authors.initials: H
authors.lastname: Kage
authors.forename: Klaus
authors.initials: K
authors.lastname: Humbeck
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bilger
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D002736:Chloroplasts / Q000378:metabolism* / Q000648:ultrastructure; D005453:Fluorescence; D018506:Gene Expression Regulation, Plant; D001467:Hordeum / Q000235:genetics / Q000254:growth & development*; D015151:Immunoblotting; D045342:Light-Harvesting Protein Complexes / Q000235:genetics / Q000378:metabolism; D058503:Mesophyll Cells / Q000378:metabolism / Q000648:ultrastructure; D010788:Photosynthesis; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011789:Quantum Theory; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012273:Ribulose-Bisphosphate Carboxylase / Q000235:genetics / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D021122:Protein Subunits; D012333:RNA, Messenger; D002734:Chlorophyll; C037184:chlorophyll b; D012273:Ribulose-Bisphosphate Carboxylase; D000077194:Chlorophyll A