Section 12A. A corporation subject to this chapter, and subject to the limitations and restrictions of section fourteen, may, by a vote of the holders of a majority of its shares outstanding and entitled to vote thereon at a meeting called therefor and with the approval of the department, issue debentures to be convertible into stock of said corporation, at the option of the holders of said debentures, in such manner, at such times, upon such terms and at such prices as may be fixed in such vote with the approval of said department and, upon the decision of the department, the shares of stock required for the conversion of said debentures shall be a part of the authorized capital of said corporation, and may be issued from time to time thereafter for the conversion of said debentures without any further authorization, order or decree by the department.