Pigmentation and Soluble Peroxidase Isozyme Patterns of Leaves of Pedilanthus tithymaloides L. variegatus as a Result of Daily Temperature Differences

In a constant environment with a narrow (less than 8 degrees C) daily temperature difference (deltat), leaves of Pedilanthus tithymaloides L. variegatus usually appeared green. After at least two days of deltat > 10 degrees C, new leaves had become green-white, and a red pigmentation appeared and increased if high deltat conditions were maintained. If plants were returned to a narrow deltat, new green leaves reappeared. Electrophoretic patterns of soluble peroxidase isozymes changed during the color changes. Three groups of electrophoretic bands occurred, and each was related to a characteristic tissue. The development of red color was correlated with the appearance of the group with the fastest electrophoretic mobility and the highest peroxidase activity.