The 2009 ASHS Annual Conference

Light quality influences the growth and morphology of plant tissues and plant development. Light-emitting diodes (LEDs) offer precise control of spectral composition and light quality, resulting in monochromatic lighting. A comparison of plantlet growth under LEDs and white fluorescent lamps was conducted by placing in vitro cultures of Dracaena ‘Lisa’ under red LEDs, blue LEDs, and white fluorescent lamps. The objective of this study was to determine the effects of red LEDs and blue LEDs on the growth of Dracaena plantlets. Explants consisting of 2.5-cm stem segments of Dracaena 'Lisa' were placed in a modified MS (Murashige & Skoog) medium supplemented with 3.0 mg/l kinetin, 0.2 mg/l IBA, adenine sulfate, sodium phosphate, inositol, and sucrose. The pH was 5.6. Jars containing one explant each were placed under red LEDs, blue LEDs, and white fluorescent lamps at a light level of 75 µmoles/m²/s and a12-hr photoperiod. After five months, explants were transferred to a fresh medium without kinetin or IBA and placed under the light treatments for six more months. We observed significant differences in the cultures grown under each light condition including the amount of callus produced, color and texture of callus produced, and number of shoots produced. The red LED treatment had the fewest number of contaminated jars. Explants grown under the red LEDs showed more base shoots per explant and higher fresh weight per explant. Our results suggest that in vitro plants grown under LEDS with particular wavelengths of light may produce the desired growth in tissue culture without the need to add certain plant hormones to the culture medium. The use of LEDs, rather than fluorescent lamps in micropropagation labs in Hawaii, could help reduce the cost of air conditioning the culture rooms and the need to frequently replace fluorescent lamps to maintain sufficient light levels in cultures.