Abstract
As a source of energy for photosynthesis, light is particularly important to leaf. Thus, plants evolved plasticity of photomorphogenesis. For example, the angiosperms have evolved an ability to avoid shade of other plants by stimulating petiole elongation. Here, we studied mechanisms of light dependent control of leaf elongation in Arabidopsis. Elevated fluence rates of red and blue light promoted the elongation of leaf blade, but they inhibited petiole elongation. Similar analysis of photoreceptor mutants indicated that the light regulation of the elongation of leaf blade and petiole was dependent on photoreceptors, especially phyB and cry1. Therefore, leaf blade and petiole are suggested to interpret the light signaling differently. We also investigated the effect of brassinosteroids and sucrose, both of which are important factors for light-dependent organ elongation. Relationship between these factors and light signal transduction pathways will be discussed.
