抄録
The bending of a plant toward the direction of intense light is called phototropism. This directional growth response is caused by the plant growth regulating substances. In this aspect, Bruinsma-Hasegawa hypothesis (1990) stated that the gradient of growth-inhibiting substances (phototropism-regulating substances) in the illuminated side is a key factor of bending during phototropic curvature. Although some phototropism-regulating substances were isolated from several plant species, the molecular mechanism underlying this phenomenon is still largely remained. The symbolic phototropism-regulating substances, cis- and trans-raphanusanins were isolated from radish hypocotyls. To understand the role of raphanusanins in phototropism and the responsible genes of growth inhibition, differential display was performed between the raphanusanin applied and control hypocotyls. We could isolate some candidate genes. Almost all positive clones were related to biotic and abiotic stress. The detailed roles and functional impacts of these genes in the growth inhibition will be presented.
