The thre unopposed candidates for reelection to the Prince George's County school board say they are not sure why no one wants to run against them, but figure they must be doing something right.

"I hope it is because people believe in what I'm doing," said Bonnie Johns, who said she knew of others who were interested in representing her district -- composed of the Capitol Heights, Seat Pleasant, Fairmont Heights, Kentland and Glenarden areas -- until they heard she was running for a new term.

"Citizen support," was the confident explanation of the fourth district's Susan Bieniasz. "I'm strong in my district. One of my major things is to be accessible."

Her district includes Colmar Manor, Bladensburg, Cheverly, Kentland and Glenarden.

"I've tried to be as accessible as possible," said board chairman Jo Anne Bell."I've enjoyed having a district that is not bashful about picking up the phone and calling when something is wrong," she said of her Forrstville, District Heights and Suitland constituents.

The school board veterans talked about the promises and problems of the public schools in separate interviews recently. The three unopposed incumbents will not face the voters again until 1984.

This year the school board is expected to approve a school facilities plan for closing 20 to 30 schools over the next five years, if the current pattern of underenrollment continues.

The closings and consolidations are imperative because of the budget squeeze brought on by TRIM, the tax-limiting amendment to the county charter. Moreover, the voters appear reluctant to come to the school system's aid with more tax dollars.

The school closings also will have an impact on the emotional issue of busing. The original 1973 plan was amended this year over the protests of Johns and other black leaders, who felt the change would lead to the closing of many inner-Beltway schools when the inevitable consolidations began.

So far, Johns has not been able to step out of her symbolic position as the "lone black school board member," though she complains that the label overstates the obvious.

She talked about her board duties in the living room of her elegant home, which from the outside could be mistaken for a museum or a library. "The loan black member. For some, that means you don't have th ability to think long range, to be able to analyze and synthesize. So I must have two roles, the general and the specific."

She is keenly aware of the bind in which many public school systems all over the country find themselves -- a seemingly nexorable drift toward a non-white majority, neglect and decline.

"If you look at history, public education periodically takes these beatings," she said. "People drift away, and when they come back it's no-man's-land, and they have to build it from scratch. It you shrotchange the school system, it comes back to haunt you."

Bieniasz also expressed an awareness of the hard facts the school board must face.

"Our unions need a raise this year. They've gone through the worst two years of inflation. And we're not going to get any more money," she said, her steel-gray eyes unblinking.

She said the board will have to decide whether to cut services in order to increase teachers' pay. It may even mean fighting some federally required programs, such as special education for the handicapped and bilingual education, because they are expensive. Bieniasz said in any case, she opposes bilingual education.

"These things are taking money away from educating the garden-variety student in the county, and the garden-variety kid has got to be educated," she said.

After four years on the board and a year as chairman, Bell still bubbles with enthusiasm for the public schools. Yet, she says a "cancer" threatens the schools and it is up to the board to prlong its "remission."

She points out that citizens seeking to amend TRIM to allow an increase in tax money for the schools could not come up with the necessary 10,000 signatures on a petition last year, despite the ready constituency of more than 8,000 school employes.

"They should have been concerned as parents about the children, they should have been concerned as employes about their jobs and they should have been concerned as citizens about the shaping of new citiznes," said Bell, who has seven children. "When they didn't sign they said, "We believe you have the funds to do the job.'"

She said the demands on the school system will take their toll in a few years, particularly on teachers who must increasingly teach out of their fields to classes that are growing larger and larger.

"We probably can survive until 1982. After that, I don't know. All the teachers we've asked to do a job and a half and cope we've already put . . . on the (road) to burnout," she said.

All three incumbents said there may be conflict in the year ahead, as competing community groups clash over the problems of school closings and racial balance. There is also the specter of a potential lawsuit, should the current busing policy or the status of school integratin itself be challenged in court.

Bell believes the busing plan enacted thisyear has put the problem behind the school board, and that the NAACP is not likely to bring suit.

Bieniasz was more cautious. Her plan to consolidate schools along neighborhood lines, which she says would have halved busing while improving the racial balance of the schools, was rejected last year.

"The busing we are doing now could do more to meet the problem. It's got to be revamped," she said. "If we do nothing and let racial isolation continue to grow, I don't know whether that provides an opening for a suit or not. I do know that if we make the wrong moves we could very well get sued."

The changes in busing affected 11 of the 16 elementary schools in Johns' district, reducing their enrollment by 17 percent, while the combined population of all county elementary schools fell by 4.7. The new busing also changed the racial mix of those schools in Johns' district from 67 percent black to 71 percent black, based on projected figures.

"I personally feel that my district has had enough schools closed and I don't want to hear about any more schools closing," she said. "If you close enough schools here, then you can just bus kids out, not in."