INFLUENCE OF PHYTOCHROME ON LEAF MONOTERPENE VARIATION IN SATUREJA-DOUGLASII

Phytochrome influenced monoterpene variation in mature leaves of Satur eja douglasii in a chemotype-dependent manner. Phytochrome significant ly increased the concentrations (mg g(-1) leaf dry weight) of camphor, pulegone and carvone and the yield (total amount mg g(-1) leaf dry we ight) in the pulegone and carvone chemotypes. However, phytochrome did not influence monoterpene concentrations nor yield in the bicyclic or isomenthone chemotypes. The phytochrome action in the pulegone type i s a low fluence response, whereas in the carvone type it is both a low and a very low fluence response. However, statistically, the composit ion (percent of total monoterpenes) that defines the chemotypes was no t significantly influenced by phytochrome and supports other studies s uggesting genetic control of the chemotype composition. The chemotypes tend to occur in a particular light environment, although one occurs across a wide range of them. The chemotype-dependent phytochrome respo nse for monoterpene variation may result from adaptation to the light environments where the chemotypes usually occur. (C) 1998 Elsevier Sci ence Ltd. All rights reserved.