Abstract
Differed from roots and stems, there is no sufficient knowledge about the nature or mechanisms of tropism of leaves. We showed that the rosette leaves of Arabidopsis thaliana exhibit negative gravitropism in dark. On the other hand, leaves did not stand up under white and red light, suggesting that red light controls the motion of leaves.
To investigate interaction between light and gravitropism of leaves,Arabidopsis seedlings were put in normal and upside-down position under white light, dark and red light for 9 hours. The angles between first and second leaves were measured before and after the treatments. As a result, all seedlings showed the leaf gravitropism, while the behavior of leaves varied among light conditions. Motion of leaves was, judged from the above data, divided into gravity-dependent and gravity-independent movement that is under control of red light. Analyses of the leaf-tropism mutants are also in progress.
