Plant and Cell Physiology, 2002, Vol. 43, No. 5 479-483
© 2002 Oxford University Press
Rhizoid Differentiation in Spirogyra: Position Sensing by Terminal Cells
1 Department of Life Science, Faculty of Science, Himeji Institute of Technology, Harima Science Park City, Hyogo, 678-1297 Japan 2 Department of Materials and Applied Chemistry, College of Science and Technology, Nihon University, Kanda-Surugadai 1-5-1, Chiyoda-ku, Tokyo, 101-8308 Japan
Some species of Spirogyra anchor themselves to the substrate by differentiating rhizoids. A rhizoid is differentiated only from the terminal cell, suggesting that this cell can recognize its terminal position in a filament. In the present study, we have analyzed the mechanism for position sensing by the terminal cell. When a filament is cut, a new cell occupies the terminal position, and three phenomena are induced: (1) the cell wall of the cut cell detaches from the new terminal cell; (2) adhesive material is secreted by the terminal cell; and (3) the terminal cell begins to differentiate a rhizoid via tip growth. All of these phenomena were inhibited by adding sorbitol to the external medium, suggesting that turgor pressure is involved in position sensing by the terminal cell. The inhibition by sorbitol was reversible. Upon cutting a filament, the distal end of a new terminal cell became convex. However, when a filament was cut in the presence of sorbitol, the distal end of a new terminal cell became less convex. Either treatment with Gd3+ or decrease in extracellular Ca2+ resulted in inhibition of all these phenomena, suggesting possible involvement of stretch-activated ion channel in position sensing by terminal cells.
3 Corresponding author: E-mail, shimmen@sci.himeji-tech.ac.jp; Fax, +81-791-58-0175.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
S.-y. Yamada, S. Sonobe, and T. Shimmen Synthesis of a Callosic Substance during Rhizoid Differentiation in Spirogyra Plant Cell Physiol., November 15, 2003; 44(11): 1225 - 1228. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Okazaki, M. Ishigami, and N. Iwasaki Temporal Relationship between Cytosolic Free Ca2+ and Membrane Potential during Hypotonic Turgor Regulation in a Brackish Water Charophyte Lamprothamnium succinctum Plant Cell Physiol., September 15, 2002; 43(9): 1027 - 1035. [Abstract] [Full Text] [PDF] |
||||
