Abstract
Circadian clock regulates a variety of developmental and physiological responses in many organisms. In plants, flowering time, lengths of hypocotyl/petiole, and leaf shape are affected by circadian clock under light and dark cycles. Molecular genetics on Arabidopsis has identified many genes that associate with circadian clock functions. Analysis of plants with mutations in these clock genes demonstrate that complex signaling network including light and plant hormone responses appear to mediate between circadian clock and the developmental changes. We have demonstrated that mutations in two clock genes LHY and CCA1 cause early flowering under light/dark cycles but late flowering, dark green/wavy leaves and semi-dwarf phenotypes under continuous light. We have identified several mutations that suppressed most of the phenotypes caused by lhy;cca1. These genes appear to function as hubs in the complex network and we discuss possible roles of them in the clock-controlled development in Arabidopsis.
