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Ca 2+ transient induced by extracellular changes in osmotic pressure in Arabidopsis leaves: differential involvement of cell wall–plasma membrane adhesion
Author(s) -
HAYASHI TERUYUKI,
HARADA AKIKO,
SAKAI TATSUYA,
TAKAGI SHINGO
Publication year - 2006
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2005.01447.x
Subject(s) - tonicity , plasmolysis , extracellular , osmotic pressure , biophysics , microbiology and biotechnology , biology , chemistry , biochemistry , cell wall
We investigated the mechanism underlying the perception of extracellular changes in osmotic pressure in Vallisneria gigantea Graebner and transgenic Arabidopsis thaliana (L.) Heynh. expressing cytoplasmic aequorin. Hypertonic and hypotonic treatments of A. thaliana leaves each rapidly induced a Ca 2+ transient. Both responses were essentially dependent on the presence of extracellular Ca 2+ and were sensitive to Gd 3+ , a potential blocker of stretch‐activated Ca 2+ channels. Immediately after plasmolysis caused by hypertonic treatment and subsequent deplasmolysis caused by hypotonic treatment, the cells did not respond to a second hypertonic treatment and exhibited an impaired adhesion of the plasma membrane (PM) to the cell wall (CW). Recovery of the responsiveness required about 6 h. By contrast, no refractory phenomenon was observed in response to hypotonic treatment. Pretreatment with cellulase completely inhibited the Ca 2+ transient induced by hypertonic treatment, but it did not affect the response to hypotonic treatment. V. gigantea mesophyll cells pretreated with cellulase exhibited an impaired adhesion of the PM to the CW. The leaf cells of multicellular plants can respond to both hypertonic and hypotonic treatments through the stretch‐activated Ca 2+ channels, whereas cellulase‐sensitive adhesion of the PM to the CW is involved only in the response to hypertonic treatment.