An analysis of long-distance water transport in the soybean stem using H215O
| Autor: | Keitaro Tanoi, Tomoko M. Nakanishi, Hirotaka Okabe, Hiroki Rai, Junko Hojo, Yousuke Hamada, Tomoyuki Ohya, Kazutoshi Suzuki |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Tritiated water
Physiology Mass flow Soil science Plant Science Models Biological chemistry.chemical_compound Oxygen Radioisotopes Xylem Botany Sieve tube element Transpiration Water transport Plant Stems fungi food and beverages Humidity Water Biological Transport Plant Transpiration Cell Biology General Medicine Permeability (earth sciences) chemistry Soybeans |
| Zdroj: | Plantcell physiology. 49(5) |
| ISSN: | 1471-9053 |
| Popis: | The lateral water movement in the intact stem of a transpiring soybean plant was analyzed quantitatively by a real-time measurement system utilizing labeled water, H(2)(15)O and gamma ray detectors. A large volume of water escaping from xylem vessels during its transport was detected. The escape of water was not influenced by evaporation from the stem surface or mass flow in the sieve tubes. It was assumed that the total amount of water transported through xylem vessels was kept almost completely constant along the internode. As a result, most of the escaped water was found to re-enter the xylem vessels, i.e. water exchange occurred. The analysis of radiographs of tritiated water suggested that the self-diffusion effect of water was strong for lateral water movement, although another driving force besides thermal motion was included in the process, and that the process was also affected by the water permeability of the plasma membrane. An analysis based on a mathematical model showed that the net volume of water which escaped from xylem vessels was not dependent on the transpiration rate of the plant. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|