Sodium transport and ion transporter gene expressions in the root of common reed ()

ヨシの根におけるナトリウム動態と輸送タンパク質の遺伝子発現の解析

樋口 恭子*; 佐藤 毅治*; 鈴井 伸郎; 丸山 哲平*; 藤巻 秀; 三輪 睿太郎*

Higuchi, Kyoko*; Sato, Takeharu*; Suzui, Nobuo; Maruyama, Teppei*; Fujimaki, Shu; Miwa, Eitaro*

Among the plants that grow on highly salinized soils, the Na content in the aerial parts of the reed () is extremely low. Previously we showed that the amounts of Na ascending via the xylem was reduced to approximately 5% and 50%, respectively, in common reed and rice (), because of the presence of shoot bases. In the current study, we analyzed the direction and rate of Na translocation within the tissues of common reed and rice under constant high salt condition by using radioactive Na and a positron-emitting tracer-imaging system (PETIS). Our analysis suggested that the roots and shoot bases of common reed have constitutive mechanisms for efficient retrieval of Na from the xylem vessel and effective transportation of Na solely to the root tips via the phloem, which is against the high Na concentration gradient in nutrient solutions. Further, these mechanisms contribute to maintaining low Na concentration in the shoots of common reed. In addition, we detected transcripts of putative Na and K transporters and channels from cells collected using laser micro dissection (LMD) in order to identify the molecules contributing to Na allocation.