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.

No abstract

How can one increase the biomass of plants, particularly orchids, in an effective way? Photoautotrophic micropropagation is an effective means of increasing the biomass of Oncidesa orchids. Using 10,000 µmol mol−1 CO2 and a photosynthetic photon flux density of 60 µmol m−2 s−1, the number of leaves and roots and shoot and root fresh and dry weights could be considerably increased, but only when cultured on Kyoto medium rather than Vacin and Went medium. Super-elevated CO2 enrichment and growth under cold cathode fluorescent lamps can positively affect the efficiency and quality of commercial production of clonal Oncidesa plantlets.

No abstract

No abstract