Two new triterpenoids, skimmiarepin A and B, which both exhibit an insect growth inhibitory activity against the silkworm, Bombyx mori L., have been isolated from the leaves and the fruit of Skimmia japonica Thunb. var. intermedia Komatsu f. repens (Nakai) Hara. Their structures have been determined by extensive 2D NMR studies and chemical methods.
The circadian system in plants is characterized by substantial cellular oscillations over an approximately 24-h period. Interactions between cellular oscillators trigger phase resets near the root meristem, resulting in localized regions of arrhythmic expression of the clock gene CCA1. The arrhythmicity of the circadian rhythm significantly impacts physiologic processes and growth; however, the exact nature of these arrhythmic regions remains unknown. In this study, we analyzed spatiotemporal patterns in CCA1 expression in arrhythmic regions using a nondestructive imaging technique. We found that formation of root arrhythmic regions involves the emergence of small spiral waves. Near the small spiral waves, the synchrony of cellular oscillations was low. Our findings provide experimental evidence that the arrhythmias are based on desynchronization of cellular oscillators and enhance our understanding of the role of circadian phenomena in root growth.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.