On Jan. 3, for the first time in eight years, the big double doors swung shut during office hours on the reception room of the California governor's office.

Steve Merksamer, chief of staff to newly inaugurated Republican Gov. George Deukmejian, ordered the change, ending eight years of demonstrations, speeches, impromptu press conferences, visits by certifiable madmen and one protester who sat in the reception area during office hours for all of last year.

The closing of those doors tells the difference between former Democratic governor Edmund G. (Jerry) Brown Jr. and his successor. Gone is the rattletrap 1974 blue Plymouth that Brown made a symbol of his administration. It has been replaced by an Oldsmobile.

Deukmejian is seeking to move into the $1.4 million governor's mansion, which Brown called a "Taj Mahal." Brown refused to move in, choosing instead a $400-a-month apartment across from the capitol.

Those are symbols. But Deukmejian is systematically dismantling many of the institutional changes made by Brown, and Republicans are proud of it.

"Most people have their own views of what Jerry Brown stood for," Merksamer said. "George Deukmejian stands for a common-sense approach to government and to public problem-solving."

In Deukmejian's first budget address, the Governor's Council on Wellness and Physical Fitness was "zero-funded." So were the Office for Citizen Initiative and Volunteerism and the California Commission on Industrial Innovation.

Many of those programs, and emphasis on such technologies as wind energy and mulching toilets and the vain plan to launch California's own satellite, won Brown the nickname "Gov. Moonbeam."

But other programs and policies slated for the ax were far more substantial and had won Brown a reputation as the most forward-looking governor in the state's history.

Deukmejian has announced that he intends to abolish as much as possible of the State Energy Commission and Coastal Zone Protection Commission, both of which flowered under Brown. Deukmejian has cut the legal staffs of the state environmental agencies responsible for monitoring air and water pollution and for fighting the opening up of offshore areas to oil drilling.

He has also said he will weaken regulations under the state's Environmental Quality Act, and has vowed to eliminate local controls over housing development. Tax credits for homeowners who install solar energy systems would be eliminated, and the budget wipes out a program that, its advocates claim, helped move California's solar industry from $30 million in sales to $330 million and an estimated 20,000 jobs in five years.

Deukmejian is increasing funds in other areas, apparently to turn the state back to an earlier era.

"Regulations which choked off growth and progress must be examined and changed where necessary," he said in his budget address. "Our clogged transportation corridors need immediate attention so that goods and people can again be moved with speed and efficiency."

Three passenger trains subsidized by the state will be eliminated, Deukmejian has said, and Adriana Gianturco, Brown's transportation director and a celebrated freeway fighter and advocate of alternative transportation, has been replaced by a former highway engineer.

Deukmejian's cabinet does not reflect Brown's selection of minorities and women. "It is safe to say . . . the Deukmejian administration will be peopled with men and women of different ethnic backgrounds and religious backgrounds and heritages," Merksamer said. "We are trying to restore a sense of competence and discipline to the governor's office and state government." CAPTION: Picture, Throughout his term, Brown refused to live in this new, $1.4 million governor's mansion, preferring an apartment by the capitol. By John Malmin, Los Angeles Times