Abstract
We developed an automatic imaging system and software to acquire the growth process of rice seedlings with image data by the minute. This technology was applied to the observation of in rice phytochrome-deficient mutant lines. They showed different photoresponsibility and growth patterns during the period from germination to flowering. Etiolated seedlings were exposed to a brief irradiation with light and their growth patterns ware examined. We found that the coleoptile growth processes are divided to five stages. In the first stage (coleoptile length was less than 1 mm) and the second stage (coleoptile length was 1-8 mm), phytochrome B (phyB) primarily regulated inhibition of coleoptile elongation, then phytochrome A (phyA) also functioned in the later stages. We also applied this technology to the observation of the tillering stage, and found that either phyA or phyB control growth patterns including the cycle of leaf appearance and maximum velocity of leaf elongation.
