title: Stimulation of Cell Elongation by Tetraploidy in Hypocotyls of Dark-Grown Arabidopsis Seedlings.
abstract: Plant size is largely determined by the size of individual cells. A number of studies showed a link between ploidy and cell size in land plants, but this link remains controversial. In this study, post-germination growth, which occurs entirely by cell elongation, was examined in diploid and autotetraploid hypocotyls of Arabidopsis thaliana (L.) Heynh. Final hypocotyl length was longer in tetraploid plants than in diploid plants, particularly when seedlings were grown in the dark. The longer hypocotyl in the tetraploid seedlings developed as a result of enhanced cell elongation rather than by an increase in cell number. DNA microarray analysis showed that genes involved in the transport of cuticle precursors were downregulated in a defined region of the tetraploid hypocotyl when compared to the diploid hypocotyl. Cuticle permeability, as assessed by toluidine-blue staining, and cuticular structure, as visualized by electron microscopy, were altered in tetraploid plants. Taken together, these data indicate that promotion of cell elongation is responsible for ploidy-dependent size determination in the Arabidopsis hypocotyl, and that this process is directly or indirectly related to cuticular function.
authors.affiliation: Laboratory of Plant Cell Wall Biology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Narukawa
authors.affiliation: Laboratory of Plant Cell Wall Biology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Yokoyama
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Komaki
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Sugimoto
authors.affiliation: Laboratory of Plant Cell Wall Biology, Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Nishitani
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics; D002452:Cell Count; D048708:Cell Growth Processes / Q000235:genetics*; D003624:Darkness; D004171:Diploidy; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D046529:Microscopy, Electron, Transmission; D020411:Oligonucleotide Array Sequence Analysis; D019441:Plant Epidermis / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D057891:Tetraploidy; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins