Abstract
In red-leaf lettuce, although the leaf is usually dark reddish-brown, if it grows by hydroponics, the anthocyanin content will decrease and it will become the shortage of coloring. In our experiments, irradiation of blue and/or UV-B light at night, cooling of hydroponic solution, and restriction of phosphorus fertilization had effects in the improvement of coloring. Accumulation of anthocyanin occurred in the immature leaf and the mature leaf was not able to obtain sufficient coloring. Then, the cloning of genes which encode biosynthesis of anthocyanin was carried out, and expression analysis was performed. The transcript level of LDOX increased in the immature leaf by which coloring was promoted. On the other hand, the transcript level of LDOX was low on the cooling conditions of hydroponics culture solution, or the restriction conditions of phosphorus fertilization. These results suggest that the transcript level of LDOX is variously controlled according to environmental factors.
