Analysis of carbon translocation in the mutant of Arabidopsis using CO and a positron-emitting tracer imaging system (PETIS)

シロイヌナズナ変異体の個体生育と炭酸同化産物動態のPETISによる解析

石井 陽平*; 鈴井 伸郎; 尹 永根; 河地 有木; 石井 里美; 栗田 圭輔  ; 島田 浩章*; 藤巻 秀

Ishii, Yohei*; Suzui, Nobuo; Yin, Y.-G.; Kawachi, Naoki; Ishii, Satomi; Kurita, Keisuke; Shimada, Hiroaki*; Fujimaki, Shu

The gene () is widely distributed in plants. The mutant of rice is known to have decreased expression of genes involved in production of storage starch. In this study, we analyzed the phenotype of mutation in Arabidopsis from the aspect of carbon movement. 20 individuals each of and WT (Col-0) were grown for 21 days. Starch accumulation in the whole plant of mutants was lower than WT. In contrast, the leaf areas and the fresh weights of were larger and heavier than those of WT. We evaluated activity of carbon assimilation and source-to-sink translocation in and WT using CO tracer gas and PETIS, a noninvasive imaging system of radiotracers. As a result, the activity of carbon assimilation per leaf weight did not show difference between and WT; however, the carbon translocation rate from the leaves to sink tissues was lower in than in WT. These results imply the following mechanisms. Biosynthesis of starch in both of the source and sink tissues is decreased by mutation. Sucrose accumulation in the sink tissue reduces the source-to-sink translocation. Excess sucrose in the source tissue causes the leaf expansion.