High CO2 Applied to Cuttings: Effects on Rooting and Subsequent Growth in Ornamental Species

CO 2 enrichment (1200 μl CO 2 /liter of air) during rooting increased the number of roots per cutting from 7.4 to 12.0 in Peperomia glabella A. Dietr. ‘Variegata’. CO 2 enrichment increased length and dry weight of root systems and fresh and dry weights of whole cuttings in P. glabella, Fuchsia magellanica Lam., Peperomia nivalis Miq., Hemigraphis alternata T. Anderson, and Begonia × argenteo-guttata V. Lemoine but not in Osmanthus heterophyllus P.S. Green ‘Rotundifolius’, Ficus pumila L., and Pelargonium × hortorum L.H. Bailey ‘Sprinter Scarlet’. After 4 weeks of growth at 330 μl CO 2 /liter, only P. nivalis retained the size differential due to CO 2 enrichment.