JXB Advance Access originally published online on March 7, 2005
Journal of Experimental Botany 2005 56(414):1255-1261; doi:10.1093/jxb/eri121
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
RESEARCH PAPER |
Uptake system of silicon in different plant species
Faculty of Agriculture, Kagawa University, Ikenobe 2393, Miki-cho, Kita-gun, Kagawa 761-0795, Japan
* To whom correspondence should be addressed. Fax: +81 87 891 3137. E-mail: maj{at}ag.kagawa-u.ac.jp
The accumulation of silicon (Si) in the shoots varies considerably among plant species, but the mechanism responsible for this variation is poorly understood. The uptake system of Si was investigated in terms of the radial transport from the external solution to the root cortical cells and the release of Si from the cortical cells to the xylem in rice, cucumber, and tomato, which differ greatly in shoot Si concentration. Symplasmic solutions of the root tips were extracted by centrifugation. The concentrations of Si in the root-cell symplast in all species were higher than that in the external solution, although the concentration in rice was 3- and 5-fold higher than that in cucumber and tomato, respectively. A kinetic study showed that the radial transport of Si was mediated by a transporter with a Km value of 0.15 mM in all species, but with different Vmax values in the order of rice>cucumber>tomato. In the presence of the metabolic inhibitor 2,4-dinitrophenol, and at low temperature, the Si concentration in the root-cell symplast decreased to a level similar to that of the apoplasmic solution. These results suggest that both transporter-mediated transport and passive diffusion of Si are involved in the radial transport of Si and that the transporter-mediated transport is an energy-dependent process. The Si concentration of xylem sap in rice was 20- and 100-fold higher than that in cucumber and tomato, respectively. In contrast to rice, the Si concentration in the xylem sap was lower than that in the external solution in cucumber and tomato. A kinetic study showed that xylem loading of Si was also mediated by a kind of transporter in rice, but by passive diffusion in cucumber and tomato. These results indicate that a higher density of transporter for radial transport and the presence of a transporter for xylem loading are responsible for the high Si accumulation in rice.
Key words: Passive diffusion, radial transport, silicon, transporter, uptake, xylem loading
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  N. Mitani, Y. Chiba, N. Yamaji, and J. F. Ma Identification and Characterization of Maize and Barley Lsi2-Like Silicon Efflux Transporters Reveals a Distinct Silicon Uptake System from That in Rice PLANT CELL, July 1, 2009; 21(7): 2133 - 2142. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. A. C. Crusciol, A. L. Pulz, L. B. Lemos, R. P. Soratto, and G. P. P. Lima Effects of Silicon and Drought Stress on Tuber Yield and Leaf Biochemical Characteristics in Potato Crop Sci., May 11, 2009; 49(3): 949 - 954. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Mitani, N. Yamaji, and J. F. Ma Identification of Maize Silicon Influx Transporters Plant Cell Physiol., January 1, 2009; 50(1): 5 - 12. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Yamaji, N. Mitatni, and J. F. Ma A Transporter Regulating Silicon Distribution in Rice Shoots PLANT CELL, May 1, 2008; 20(5): 1381 - 1389. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. F. Ma, N. Yamaji, K. Tamai, and N. Mitani Genotypic Difference in Silicon Uptake and Expression of Silicon Transporter Genes in Rice Plant Physiology, November 1, 2007; 145(3): 919 - 924. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Xu, N. Yamaji, R. Shen, and J. F. Ma Sorghum Roots are Inefficient in Uptake of EDTA-chelated Lead Ann. Bot., May 1, 2007; 99(5): 869 - 875. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Yamaji and J. F. Ma Spatial Distribution and Temporal Variation of the Rice Silicon Transporter Lsi1 Plant Physiology, March 1, 2007; 143(3): 1306 - 1313. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Fauteux, F. Chain, F. Belzile, J. G. Menzies, and R. R. Belanger The protective role of silicon in the Arabidopsis-powdery mildew pathosystem PNAS, November 14, 2006; 103(46): 17554 - 17559. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. HODSON, P. J. WHITE, A. MEAD, and M. R. BROADLEY Phylogenetic Variation in the Silicon Composition of Plants Ann. Bot., November 1, 2005; 96(6): 1027 - 1046. [Abstract] [Full Text] [PDF]
|
|