Sensitivity to Humidity and Temperature in Darkness of the Photoinduction of S-Adenosyl-L-Methionine Decarboxylase Activity in Leaves of Pharbitis nil

The activity of S-adenosyl-L-methionine decarboxylase (SAMD)in leaves of Pharbitis nil increased maximally at "lights-on"after growth in darkness for 16 h at 21 to 25°C and 30%to 40% relative humidity. Under other condition, less SAMD activitywas induced. The photoinduction of SAMD was also observed inleaves of many other plant species. (Received December 14, 1994; Accepted April 6, 1995)