Sucrose Concentration, Light Intensity, and CO2 Concentration Affect Growth and Development of Micropropagated Carnation

Abstract

Carnation (Dianthus caryophyllus L.) ‘Purple Beauty’ at micropropagation stage 3 was cultured under two levels each of medium sucrose concentration (0 and 30 g·L-1), photosynthetic photon flux density (50 and 200 μmol·m-2·s-1 PPFD), and CO2 concentration (350 and 1,000 μmol·mol-1), in a factorial experimental design, consisting of all eight possible treatment combinations. Shoot tip explants, obtained from in vitro-grown plantlets, were cultured on 50 mL agar-solidified Murashige and Skoog medium per container. Each culture container was sealed with a rigid lid vented by a high-efficiency particulate air filter attached to a 10 mm diameter hole made in the lid center, with an estimated number of 2.8 air exchanges per hour. All cultures were maintained for four weeks at 24°C/22°C (day/night) temperatures, 70%–80% relative humidity, and a 16 h/8 h (day/night) photoperiod was provided by white light-emitting diodes. The treatment combining high light intensity (200 μmol·m-2·s-1), high CO2 concentration (1,000 μmol·mol-1), and without supplementation of sucrose to the medium (i.e., photo-autotrophic conditions) resulted in better plantlet growth and development, with higher values being observed in terms of total fresh weight, tissue water content, leaf length, leaf width, and total chlorophyll content than in plantlets grown under the other treatments.