Fusion of oil bodies in endosperm of oat grains.
Few microscopical studies have been made on lipid storage in oat grains, with variable results as to the extent of lipid accumulation in the starchy endosperm. Grains of medium- and high-lipid oat (Avena sativa L.) were studied at two developmental stages and at maturity, by light microscopy using different staining methods, and by scanning and transmission electron microscopy. Discrete oil bodies occurred in the aleurone layer, scutellum and embryo. In contrast, oil bodies in the starchy endosperm often had diffuse boundaries and fused with each other and with protein vacuoles during grain development, forming a continuous oil matrix between the protein and starch components. The different microscopical methods were confirmative to each other regarding the coalescence of oil bodies, a phenomenon probably correlated with the reduced amount of oil-body associated proteins in the endosperm. This was supported experimentally by SDS-PAGE separation of oil-body proteins and immunoblotting and immunolocalization with antibodies against a 16 kD oil-body protein. Much more oil-body proteins per amount of oil occurred in the embryo and scutellum than in the endosperm. Immunolocalization of 14 and 16 kD oil-body associated proteins on sectioned grains resulted in more heavy labeling of the embryo, scutellum and aleurone layer than the rest of the endosperm. Observations on the appearance of oil bodies at an early stage of development pertain to the prevailing hypotheses of oil-body biogenesis.
Heneen
Waheeb K
WK
Department of Plant Breeding and Biotechnology, Swedish University of Agricultural Sciences, P.O.B. 101, 23053 Alnarp, Sweden. waheeb.heneen@ltj.slu.se
Karlsson
Gunnel
G
Brismar
Kerstin
K
Gummeson
Per-Olov
PO
Marttila
Salla
S
Leonova
Svetlana
S
Carlsson
Anders S
AS
Bafor
Maureen
M
Banas
Antoni
A
Mattsson
Bengt
B
Debski
Henryk
H
Stymne
Sten
S
D018554:Avena / Q000166:cytology* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D008055:Lipids / Q000032:analysis / Q000096:biosynthesis*; D008854:Microscopy, Electron; D010938:Plant Oils / Q000737:chemistry; D010940:Plant Proteins / Q000032:analysis; D012639:Seeds / Q000166:cytology* / Q000648:ultrastructure; D013194:Staining and Labeling
D008055:Lipids; D010938:Plant Oils; D010940:Plant Proteins