Epicuticular Wax Formation on Carnation Plantlets Regenerated from Shoot Tip Culture1

Abstract

Abstract Epicuticular wax fine structure on leaves from carnation ( Dianthus caryophyllus L.) grown in the greenhouse or regenerated from shoot tip culture was compared by scanning electron microscopy. Wax rods densely covered the glaucous leaf surface of greenhouse-grown plants. Irregularly-shaped wax plates were observed on leaves of glaucous plantlets, but no structured wax was seen on non-glaucous plantlets, which comprised the majority of plantlets. During 2½ weeks in the greenhouse, increasing amounts of structured epicuticular wax developed on leaves of glaucous plantlets but not of non-glaucous plantlets. The low survival rate of carnation plantlets regenerated in vitro may be explained by their lack of epicuticular wax structure which results in excess desiccation when they are transferred from in vitro conditions to the greenhouse.