Salt Tolerance in Suspension Cultures of Sugar Beet 1: Induction of Na+/H+ Antiport Activity at the Tonoplast by Growth in Salt
AUTOR(ES)
Blumwald, Eduardo
RESUMO
Cell suspension cultures of sugar beet were grown at various salinities (0-200 millimolar NaCl). Their tolerance to Na+ was comparable to that of the intact plant. Tonoplast vesicles were prepared by sucrose density gradient centrifugation of microsomal membranes and shown to be highly purified. The vesicles were subjected to a pH jump in the presence of acridine orange and the rate of recovery of fluorescence after addition of Na+ was used as a measure of Na+-dependent H+ efflux. In the presence of K+ and valinomycin, the Na+/H+ antiport showed saturation kinetics. Increasing Na+ in the growth medium did not change the apparent Km for Na+, but increased Vmax to about twice the control value, suggesting a specific induction of antiport synthesis by salt.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1056467Documentos Relacionados
- Inhibition of Na+/H+ Antiport Activity in Sugar Beet Tonoplast by Analogs of Amiloride 1
- Rapid Induction of Na+/H+ Exchange Activity in Barley Root Tonoplast 1
- NaCl Induces a Na+/H+ Antiport in Tonoplast Vesicles from Barley Roots 1
- Tonoplast Na+/H+ Antiport Activity and Its Energization by the Vacuolar H+-ATPase in the Halophytic Plant Mesembryanthemum crystallinum L.
- A specific mutation abolishing Na+/H+ antiport activity in hamster fibroblasts precludes growth at neutral and acidic pH.