GROWTH AND PHYSIOLOGICAL CHARACTERISTICS OF PLANTLETS OF SPATHIPHYLLUM ´SENSATION´ IN ROOTING PHASE AS AFFECTED BY SUCROSE-FREE MEDIUM AND DIFFUSIVE VENTILATION

Regenerated shoots of Spathiphyllum ‘Sensation’ were transferred in rooting medium with or without sucrose in the vessels capped with Polypropylene film as the closed system or with polypropylene film embedding a round gas-permeable membrane for diffusive ventilation. The shoots could survive and grow normally on the sucrose-free medium, the fresh weight increment, dry weight percentage and the number of new leaves of plantlets as growth indexes were improved with the diffusive ventilation. Rooting of the plantlets had a sensitive response to the diffusive ventilation, and the plants produced more roots with initiating to root 3-5 days earlier. CO₂ concentration was at a low level of about 80 mol.mul^-1 during the photo period and CO₂ supplement was limited in the closed vessels. Chlorophyll content and photosynthesis rate of leaves with the ventilation were higher than with the closure. The plantlets cultured under the diffusive ventilation grew better with a lower rate of death and aberrance as transplanted into the peat substrates in the greenhouse.