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

In insects. juvenile hormones (JHs) regulate physiological processes such a s metamorphosis and reproduction but their presence in plants is poorly und erstood. The temporal and tissue distribution of insect juvenile hormone II I (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 tim e course, from the seedling to the senescent plant. Juvenile hormone III le vels 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 olde r 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 synthesi s and/or storage. (C) 1999 Elsevier Science Ltd. All rights reserved.