title: In vitro growth and single-leaf photosynthetic response of Cymbidium plantlets to super-elevated CO2 under cold cathode fluorescent lamps.
abstract: To examine the effectiveness of super-elevated (10,000 micromol mol(-1)) CO(2) enrichment under cold cathode fluorescent lamps (CCFL) for the clonal propagation of Cymbidium, plantlets were cultured on modified Vacin and Went (VW) medium under 0, 3,000 and 10,000 micromol mol(-1) CO(2) enrichment and two levels of photosynthetic photon flux density (PPFD, 45 and 75 micromol m(-2) s(-1)). Under high PPFD, 10,000 micromol mol(-1) CO(2) increased root dry weight and promoted shoot growth. In addition, a decrease in photosynthetic capacity and chlorosis at leaf tips were observed. Rubisco activity and stomatal conductance of these plantlets were lower than those of plantlets at 3,000 micromol mol(-1) CO(2) under high PPFD, which had a higher photosynthetic capacity. On the other hand, plantlets on Kyoto medium grown in 10,000 micromol mol(-1) CO(2) under high PPFD had a higher photosynthetic rate than those on modified VW medium; no chlorosis was observed. Furthermore, growth of plantlets, in particular the roots, was remarkably enhanced. This result indicates that a negative response to super-elevated CO(2) under high PPFD could be improved by altering medium components. Super-elevated CO(2) enrichment of in vitro-cultured Cymbidium could positively affect the efficiency and quality of commercial production of clonal orchid plantlets.
authors.affiliation: The United Graduate School of Agricultural Science, Ehime University, Matsuyama, Ehime, 790-8566, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Norikane
authors.forename: Takejiro
authors.initials: T
authors.lastname: Takamura
authors.forename: Masahiro
authors.initials: M
authors.lastname: Morokuma
authors.forename: Michio
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D003470:Culture Media; D008027:Light; D029595:Orchidaceae / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects; D010788:Photosynthesis; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D054046:Plant Stomata; D012273:Ribulose-Bisphosphate Carboxylase
chemical_list: D003470:Culture Media; D002245:Carbon Dioxide; D012273:Ribulose-Bisphosphate Carboxylase