Ca2+ transient induced by extracellular changes in osmotic pressure in Arabidopsis leaves: differential involvement of cell wall–plasma membrane adhesion

• Published in: Plant, cell and environment cell and environment, 2006-04, Vol.29 (4), p.661-672
• Main Authors: HAYASHI, TERUYUKI, HARADA, AKIKO, SAKAI, TATSUYA, TAKAGI, SHINGO
• Format: Article
• Language: English
• Subjects: Actin Cytoskeleton - drug effects; Actin Cytoskeleton - ultrastructure; Actins - antagonists & inhibitors; aequorin; Aequorin - genetics; Apoproteins - genetics; Arabidopsis - cytology; Arabidopsis - drug effects; Arabidopsis - physiology; Arabidopsis Proteins - antagonists & inhibitors; Arabidopsis Proteins - physiology; Biological and medical sciences; Bridged Bicyclo Compounds, Heterocyclic - pharmacology; Calcium - metabolism; Calcium Channels - physiology; Cell Adhesion - physiology; Cell Membrane - physiology; Cell physiology; Cell Wall - physiology; Cellulose - metabolism; cellulose microfibrils; Cytoplasmic Streaming - physiology; deplasmolysis; Fundamental and applied biological sciences. Psychology; hypertonic treatment; hypotonic treatment; Mechano‐perception; Microfibrils - physiology; Osmotic Pressure; Plant Leaves - cytology; Plant Leaves - metabolism; Plant Leaves - physiology; Plant physiology and development; Plasma membrane and permeation; plasmolysis; Recombinant Proteins - genetics; Signal Transduction; Thiazolidines - pharmacology; Vallisneria gigantea (mesophyll cell)
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/j.1365-3040.2005.01447.x

ABSTRACT 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 Ca2+ transient. Both responses were essentially dependent on the presence of extracellular Ca2+ and were sensitive to Gd3+, a potential blocker of stretch‐activated Ca2+ 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 Ca2+ 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 Ca2+ channels, whereas cellulase‐sensitive adhesion of the PM to the CW is involved only in the response to hypertonic treatment.