When you say from the bottom, do you mean they're arising from the roots under the compost, or actually growing off the mainstem of the plant above ground?

There is one from the main stem above ground, and, there is one from under the compost.

Your Acer has been grafted and these green shoots are coming up from below the graft. You'll need to cut them off and remove any others that appear.

Thanks very much for your help.