Formation of epicuticular wax and its effect on water loss in cabbage plants regenerated from shoot-tip culture

Abstract

Observation by scanning electron microscopy (SEM) revealed that cabbage plants in vitro had no structured epicuticular wax whereas plants grown in a growth chamber or in the greenhouse had considerable amounts of structured epicuticular wax. Plants grown in vitro developed increasing amounts of structured epicuticular wax after transfer to the greenhouse. Water loss per unit leaf area was greater in plants recently removed from in vitro conditions than in either plants grown in the growth chamber or in cultured plants that had been hardened off. Epicuticular wax was formed in plants grown in vitro at 35% relative humidity indicating that relative humidity is an important factor in the in vitro development of wax. The contribution of light to the formation of epicuticular wax and the relationship of the wax to survival of the plants when they are removed from in vitro culture are discussed.