| Autor: |
N T, Wood, A C, Allan, A, Haley, M, Viry-Moussaïd, A J, Trewavas |
| Rok vydání: |
2000 |
| Předmět: |
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| Zdroj: |
The Plant journal : for cell and molecular biology. 24(3) |
| ISSN: |
0960-7412 |
| Popis: |
Two novel approaches for the study of Ca2+-mediated signal transduction in stomatal guard cells are described. Stimulus-induced changes in guard-cell cytosolic Ca2+ ([Ca2+]cyt) were monitored using viable stomata in epidermal strips of a transgenic line of Nicotiana plumbaginifolia expressing aequorin (the proteinous luminescent reporter of Ca2+) and in a new transgenic line in which aequorin expression was targeted specifically to the guard cells. The results indicated that abscisic acid (ABA)-induced stomatal closure was accompanied by increases in [Ca2+]cyt in epidermal strips. In addition to ABA, mechanical and low-temperature signals directly affected stomatal behaviour, promoting rapid closure. Elevations of guard-cell [Ca2+]cyt play a key role in the transduction of all three stimuli. However, there were striking differences in the magnitude and kinetics of the three responses. Studies using Ca2+ channel blockers and the Ca2+ chelator EGTA further suggested that mechanical and ABA signals primarily mobilize Ca2+ from intracellular store(s), whereas the influx of extracellular Ca2+ is a key component in the transduction of low-temperature signals. These results illustrate an aspect of Ca2+ signalling whereby the specificity of the response is encoded by different spatial or kinetic Ca2+ elevations. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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