Abstract
Environmental pH is a key factor influencing plant growth and development. In our previous study, we found that Arabidopsis germinated seeds or seedlings grow well over the pH range 4.2 to 10 and are capable of neutralizing acidified or alkalized culture media.
In this study, we examined whether proton pumps such as plasma membrane H+-ATPase, vacuolar H+-ATPase, and vacuolar H+-PPase, were involved in the neutralization of culture media. Treatment of seedlings with vanadate promoted the neutralization of acidic medium (pH 4.2), whereas fusicoccin slowed down it. In contrast, the application of vanadate to seedlings hindered the neutralization of alkaline medium (pH 10.0), and fusicoccin promoted it. These results suggest that plasma membrane H+-ATPase primarily functions in the neutralization of alkaline environments.
Using Arabidopsis mutants, we are now investigating the involvement of various transporters including plasma membrane Na+/H+ antiporter (SOS1) in medium neutralization.
