Search PubMed⌕ Search

Biomedical subjects

XQ Wang

Publications and source records attributed to XQ Wang.

At least 19 recordsLinked to original sources
PubMed2000

Poly

Explore the source record for details and available documents.

Journal Article↗
PubMed1998

Differential responses of abaxial and adaxial guard cells of broad bean to abscisic acid and calcium

Regulation by abscisic acid (ABA) and Ca2+ of broad bean (Vicia faba) abaxial and adaxial guard cell movements and inward K+ currents were compared. One millimolar Ca2+ in the bathing medium inhibited abaxial stomatal opening by 60% but only inhibited adaxial stomatal opening by 15%. The addition of 1 &mgr;M ABA in the bathing medium resulted in 80% inhibition of abaxial but only 45% inhibition of adaxial stomatal opening. Similarly, ABA and Ca2+ each stimulated greater abaxial stomatal closure than adaxial stomatal closure. Whole-cell patch-clamp results showed that the inward K+ currents of abaxial guard cells were inhibited by 60% (-180 mV) in the presence of 1.5 &mgr;M Ca2+ in the cytoplasm, whereas the inward K+ currents of adaxial guard cells were not affected at all by the same treatment. Although 1 &mgr;M ABA in the cytoplasm inhibited the inward K+ currents to a similar extent for both abaxial and adaxial guard cells, the former were more sensitive to ABA applied externally. These results suggest that the abaxial stomata are more sensitive to Ca2+ and ABA than adaxial stomata in regard to stomatal opening and closing processes and that the regulation of the inward K+ currents by ABA may not proceed via a Ca2+-signaling pathway in adaxial guard cells. Therefore, there may be different pathways for ABA- and Ca2+-mediated signal transduction in abaxial and adaxial guard cells.

Journal Article↗