SIMILARITY OF GROWTH-PATTERNS BETWEEN PLANTLETS AND SEEDLINGS OF BRASSICA-CAMPESTRIS L UNDER DIFFERENT INVITRO ENVIRONMENTAL-CONDITIONS

Explants and seeds of Brassica compestris L. were cultured on Murashige & Skoog (1962) medium with and without sucrose in a vessel with different numbers of air changes per hour under different PPF (photosynthetic photon flux) conditions. The growth and development of plantlets in the vessel were similar to those of seedlings when cultured under the same in vitro environmental conditions. The growth and development of plantlets/seedlings were greater for treatments with a higher number of air changes per hour and a higher PPF regardless of the sucrose concentration in the culture medium. The CO2 concentration in the vessel with a lower number of air changes per hour decreased to approximately 100 ppm during the photoperiod on day 21 due to the photosynthetic activities of the plantlets/seedlings. The low CO2 concentration, in turn, reduced the net photosynthetic rate of plantlets/seedlings in the vessel, and thus affected their growth and development.