The Prince George's County School Board voted last night to reduce busing for desegregation in the county by almost 25 percent, altering for the first time a desegregation plan put into effect by a federal court order seven years ago.

The plan will allow 3,772 elementary school students to attend schools in or closer to their neighborhoods starting next fall.

The vote was seven to one, with the "no" cast by the board's only black member, Bonnie Johns, who said the plan "hits one race [blacks] more heavily." Another member, Chester Whiting, abstained.

One fear of the plan's opponents is that it will lead to underenrollment at many predominantly black schools, which will then be threatened with closing.

The plan will affect 75 of the system's 145 elementary schools and will allow 1,400 more elementary students to walk to school. The bus rides of more than 2,300 others will be shortened. About 70 percent of the students affected by the new busing patterns are black.

Officails of the county NAACP branch, which filed the suit against the school system that led to the federal court desegregation order in 1973, said last night they expect to take the board back to court on grounds that the plan is an effort to resegregate the school system.

The also said they plan to file a complaint against the board with the U.S. Office of Civil Rights.

The plan the board approved is the result of months of effort by a citizens committee the board set up last fall to explore ways to reduce "unnecessary" busing for desegregation.

The current board and past ones had considered dozens of ways to change the busing pattern that the U.S. District Court in Baltimore designed and implemented in January 1973.

Since that plan went into effect, the county's racial makeup and school-age population have shifted dramatically, but the board had never, before last night, been able to agree on modifications.

In the years since the busing order was put into effect, the county's black student population has jumped from about 25 percent of the system to nearly 50 percent, a circumstance that has led to increasing resegregation of the school system.

As a result there are now many instances of cross-busing where black students are bused to predominantly black schools and students living in integrated areas are transported daily to integrated schools miles across the county.

Although board members stated repeatedly over the past three years their goal of reducing busing as a means of discouraging "white flight" and other social ills, they had turned down all busing modification proposals out of fear of new court suits or because of political bickering among themselves.

In recent weeks, with board elections drawing closer, sentiment on the board shifted in favor of adopting a plan to curtail at least some of the busing.

About 16,000 of the school system's 127,000 students ride buses each day for desegregation purposes, and of these almost all are elementary pupils. About 60,000 additional students in both elementary and secondary schools ride buses each day simply to get to school.

The plan adopted last night is designed to eliminate as much cross-busing as possible without substantially altering the racial balance of the elementary schools.

The citizens committee had explored returning all elementary pupils to their neighborhood schools, but backed away from that idea when it discovered that the number of one-race schools in the county would increase dramatically.

As a result, the committee recommend the much smaller plan that the board approved last night.

After approving the committe's plan last night, the board voted down a second proposal, made by board member Sue Bieniasz, that would have taken 10,000 of the 16,000 children now bused for desegregation off the buses. That proposal included a recommendation to close 14 schools, which many board members found objectionable.

Johns, the black board member who voted against the successful plan, said, "bad situations often provoke terible solutions. To me, this busing proposal hits one race more heavily than the other. As a result of this plan five schools [in her predominantly black district] are highly vulnerable for closing" because of changes in busing and therefore enrollment.

"It is in violation of good education to only be talking about one part of the remedy" for segregation rather than considering such issues as curriculum, extracurricular activities, transfer policies and special programs, she said.

Board member A. James Golato, one of those who voted for the plan, said, "What does our inaction [over the past few years] do for education? If we did nothing at all we would have more segregation every year than we have now. What we're trying to do is stop that cycle and get some stability in this county. The very purpose of busing for desegrgation is not being accomplished for this small group of people [the children who will no longer be bused]. It is busing which is not helping integration."