Unless otherwise authorized as provided in this section, seventy-five percent of the appropriations made by the legislative assembly for the line items of salaries and wages and operating expenses for any state institution, department, board, commission, or bureau in the executive branch of state government for the biennium, except institutions under the jurisdiction and supervision of the state board of higher education, shall become available on the first day of July next succeeding the enactment by the legislative assembly. The remaining twenty-five percent of any such appropriations shall be available only at the beginning of the fourth quarter of the biennium. No state institution, department, board, commission, or bureau in the executive branch of government for which an appropriation for salaries and wages and operating expenses is made may disburse more than seventy-five percent of such appropriation during the first eighteen months of the biennium nor incur any expense or liability which shall be discharged from such appropriation or for which such appropriation shall become available. Whenever it is made to appear to the emergency commission by a verified petition submitted by a state institution, department, board, commission, or bureau in the executive branch of state government that the percentage of the appropriation for operating expenses allocated for the first three-quarters of the biennium will not be adequate to properly perform its duties and functions, because of seasonal or other unusual circumstances, it may authorize a revision of the allocated percentage in any such items, except salaries and wages, provided it will not deprive such state institution, department, board, commission, or bureau from maintaining its office for the fourth quarter of the biennium.