Role of Calcium in Signal Transduction of Commelina Guard Cells.
AUTOR(ES)
Gilroy, S
RESUMO
The role of cytosolic Ca2+ in signal transduction in stomatal guard cells of Commelina communis was investigated using fluorescence ratio imaging and photometry. By changing extracellular K+, extracellular Ca2+, or treatment with Br-A23187, substantive increases in cytosolic Ca2+ to over 1 micromolar accompanied stomatal closure. The increase in Ca2+ was highest in the cytoplasm around the vacuole and the nucleus. Similar increases were observed when the cells were pretreated with ethyleneglycol-bis-(o-aminoethyl)tetraacetic acid or the channel blocker La3+, together with the closing stimuli. This suggests that a second messenger system operates between the plasma membrane and Ca2+-sequestering organelle(s). The endogenous growth regulator abscisic acid elevated cytosolic Ca2+ levels in a minority of cells investigated, even though stomatal closure always occurred. Ca2+-dependent and Ca2+-independent transduction pathways linking abscisic acid perception to stomatal closure are thus indicated.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=160004Documentos Relacionados
- Two Transduction Pathways Mediate Rapid Effects of Abscisic Acid in Commelina Guard Cells.
- Convergence of the abscisic acid, CO2, and extracellular calcium signal transduction pathways in stomatal guard cells.
- Evidence for an Extracellular Reception Site for Abscisic Acid in Commelina Guard Cells.
- Angiogenesis: role of calcium-mediated signal transduction.
- Abscisic acid signal transduction in guard cells is mediated by phospholipase D activity
