Do you want to hide the lines or the entire axes?
The problem is you are overwriting the handle to the previous plot each loop. If you want to capture them all, you need to create a vector of handles.
for i=1:size(V)
handles.p2(i)=plot(........)
hold on
end
The, to set them all off in one command, you can use
set(handles.p2,'Visible','off')
