Abstract：The V-H+-ATPase in plant cell transports can proton into the vacuole and forms the electrochemical gradients across the membranes, which energizes the secondary transport systems presented on the membranes. We applied plants Mesembryanthemum crystallinum, Zea mays, Aplum graveolens, and Daucus carota, and initially observed that the V-H+-ATPase from different plant species performed special active peaks of the proton transportation and vary isoforms of subunit A during circadian rhythm and/or stress. Repeat experimental results showed that there were two strong peaks of proton transportation in the leaves of M.crystallinum occurred at the time of 3 and 18 o'clock, respectively. In the leaves of A.graveolens, D.carota and Z.mays only one strong peak was observed: the active peak in the leaves of A.graveolens and D.carota was observed at 15 and 12 o'clock, respectively; the active peaks in the leaves of Z.mays was revealed during the time periods of 15~18 o'clock. The expressions of the isoforms of the subunit A of the V-H+-ATPase from above plant were observed: two isoforms were revealed in the leaves of M.crystallinum, which was not affected by salt stress and day/night change; four isoforms of the subunit A were observed in the leaves of Z.mays, the number of the isoforms was not affected by salt stress; three isoform of the subunit A from the leaves of A.graveolens did not show much differences during day/night change, but appeared a new isoform after salt stress; In the leaves of D.carota, the isoform of the subunit A was changed during day/night time period, at 8 o'clock two isoforms were observed, while at 18 o'clock only one was revealed, the isoforms of the subunit A from D.carota were not affected by salt stress. The proton transportation and the isoforms of the subunit A of the V-H+-ATPase from above plant species suggest the specific phenomenon related plant species, which may be an interesting base for the studies of the role of gene silencing and proteases.
