Developmental distribution of insect juvenile hormone III in the sedge, Cyperus iria L.

In insects. juvenile hormones (JHs) regulate physiological processes such as metamorphosis and reproduction but their presence in plants is poorly understood. The temporal and tissue distribution of insect juvenile hormone III (JH III): methyl-10R,11-epoxy-3,7,11-trimethyl 2E,6E-dodecadienoate, was determined in sedge (Cyperus iria L.) over an eight month developmental time course, from the seedling to the senescent plant. Juvenile hormone III levels increased in immature plants until flowering, at which rime cessation of plant growth and a transient decrease in JH III content was observed. In mature plants. JH III levels in all plant tissues again increased. In older plants. JH III levels in aerial tissues declined as they became senescent. This decrease was not observed in root tissues which remained viable over the duration of the time course. Moreover, 85% of the total JH III in the plant was present in the roots, suggesting that they are a site of synthesis and/or storage. (C) 1999 Elsevier Science Ltd. All rights reserved.