52Fe Translocation in Barley as Monitored by a Positron-Emitting Tracer Imaging System (PETIS): Evidence for the Direct Translocation of Fe from Roots to Young Leaves via Phloem |
| |
Authors: | Tsukamoto, Takashi Nakanishi, Hiromi Uchida, Hiroshi Watanabe, Satoshi Matsuhashi, Shinpei Mori, Satoshi Nishizawa, Naoko K. |
| |
Affiliation: | 1Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657 Japan 2Central Research Laboratory, Hamamatsu Photonics K.K., Hamamatsu, Shizuoka, 434-0041 Japan 3Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, Gunma, 370-1292 Japan |
| |
Abstract: | The real-time translocation of iron (Fe) in barley (Hordeumvulgare L. cv. Ehimehadaka no. 1) was visualized using the positron-emittingtracer 52Fe and a positron-emitting tracer imaging system (PETIS).PETIS allowed us to monitor Fe translocation in barley non-destructivelyunder various conditions. In all cases, 52Fe first accumulatedat the basal part of the shoot, suggesting that this regionmay play an important role in Fe distribution in graminaceousplants. Fe-deficient barley showed greater translocation of52Fe from roots to shoots than did Fe-sufficient barley, demonstratingthat Fe deficiency causes enhanced 52Fe uptake and translocationto shoots. In the dark, translocation of 52Fe to the youngestleaf was equivalent to or higher than that under the light condition,while the translocation of 52Fe to the older leaves was decreased,in both Fe-deficient and Fe-sufficient barley. This suggeststhe possibility that the mechanism and/or pathway of Fe translocationto the youngest leaf may be different from that to the olderleaves. When phloem transport in the leaf was blocked by steamtreatment, 52Fe translocation from the roots to older leaveswas not affected, while 52Fe translocation to the youngest leafwas reduced, indicating that Fe is translocated to the youngestleaf via phloem in addition to xylem. We propose a novel modelin which root-absorbed Fe is translocated from the basal partof the shoots and/or roots to the youngest leaf via phloem ingraminaceous plants. |
| |
Keywords: | Barley - Fe translocation - Phloem - Positron-emitting tracer - Real-time imaging - Xylem |
本文献已被 Oxford(免费) 等数据库收录! |
|