Regulation of Apoplastic pH in Source Leaves of Vicia faba by Gibberellic Acid 1
AUTOR(ES)
Aloni, Beny
RESUMO
Leaf discs of broad bean (Vicia faba L.), peeled on the spongy mesophyll side, rapidly altered the pH of the surrounding medium (apoplast). Using pH indicator paper appressed against the leaf, immediately after peeling, initial apoplastic pH was estimated to be 4.5. Changes in the apoplastic pH were measured with a microelectrode placed into a 100-microliter drop of an unbuffered solution (2 millimolar KCl, 0.5 millimolar CaCl2, and 200 millimolar mannitol) on the peeled surface. Discs acidified the medium until the pH stabilized at about 5.0 (about 10 minutes). Acidification was inhibited by 50 micromolar sodium vanadate, an inhibitor of the plasmalemma H+-ATPase and attenuated by omitting the osmoticum or potassium ions from the medium. Fusicoccin (10 micromolar) greatly enhanced the rate of acidification. The presence of 0.1 to 1 micromolar gibberellic acid resulted in a slower rate of medium acidification. Gibberellic acid appeared to modulate the activity of the H+-translocating ATPase located at the plasma membrane of the mesophyll cells.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1055582Documentos Relacionados
- Enhancement of [14C]Sucrose Export from Source Leaves of Vicia faba by Gibberellic Acid 1
- Abscisic Acid Movement into the Apoplastic solution of Water-Stressed Cotton Leaves: Role of Apoplastic pH
- Apoplastic pH and Fe3+ Reduction in Intact Sunflower Leaves1
- Apoplastic pH and Ammonium Concentration in Leaves of Brassica napus L.
- Cutin Biosynthesis in Vicia faba Leaves: Effect of Age 1