The bridge and park commission, in the issuance of any bonds or securities pursuant to its authority under this chapter, or any other statute, may, in its discretion, authorize and have inserted in such bonds or securities a provision to the effect that such bonds or securities shall constitute a lien upon all or any specified portion of the property which the commission is authorized to transfer, convey or sell to private individuals, with right of foreclosure of such lien to be vested in the holder or holders of such securities or bonds, upon terms and conditions such as may be approved by said commission and set out in such securities or bonds, and such provisions thus approved and inserted therein shall constitute and effect a valid lien on the property as specified. Further, all or any part of the proceeds from the authorized transfer, conveyance or sale of lots or other property of the commission to private individuals may be pledged by the commission, in its discretion, as security for any bonds or other securities lawfully issued or to be issued by it, upon such terms and conditions as said commission may provide.