In addition to the purposes stated in article eight, section seven of this Constitution, the Commonwealth may be authorized by law to create debt and to issue bonds to the amount of seventy million dollars ($70,000,000) for the acquisition of land for State parks, reservoirs and other conservation and recreation and historical preservation purposes and for participation by the Commonwealth with political subdivisions in the acquisition of land for parks, reservoirs and other conservation and recreation and historical preservation purposes, subject to such conditions and limitations as the General Assembly may prescribe.