Application of Chondroitin Sulfate on Organogenesis of Two <i>Cymbidium</i> spp. under Different Sources of Lights

The aim of this study was to present chondroitin sulfate as a plant growth regulator and to give an overview about light effects on PLBs (protocorm like bodies) culture of Cymbidium dayanum and Cymbidium finlaysonianum cultured in vitro . Chondroitin sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars N-acetylgalactosamine and glucuronic acid. It is widely used as a material for food ingredients, cosmetics and medicine. PLBs were cultured on modified MS medium containing different concentration of chondroitin sulfate (0, 0.1, 1 and 10 mg/l), under four sources of lights: conventional white fluorescent tube, red LED, green LED and blue LED. In C. dayanum, 100% PLBs formation rate was observed at 0.1 mg/l chondroitin sulfate with modified MS medium under green LED and 1 mg/l chondroitin sulfate under blue LED; the maximum shoots and roots formation were observed under green LEDs (93% and 80% respectively) when media contained 0.1 mg/l chondroitin sulfate. In C. finlaysonianum , every concentrations of chondroitin sulfate enhanced the growth rate of PLBs when compared to control treatment, under all four sources of lights. The highest values were recorded with 0.1 mg/l chondroitin sulfate which induced 100% PLBs formation under blue LED, while 10 mg/l chondroitin sulfate had induced 100% PLBs formation under green LED. The highest percentage of shoots (73%) was initiated in the medium containing 10 mg/l chondroitin sulfate under green LED. Plant development was strongly influenced by the light quality and plant growth regulator functions as chemical messengers for intercellular communication of plant. The results demonstrated that low concentrations of chondroitin sulfate could promote PLBs, shoots and roots formation of Cymbidium spp. under green and blue LED.