George Bush and Michael Dukakis painted sharply differing pictures of American business Friday, with the vice president citing a defense plant as an example of U.S. competitiveness and the Massachusetts governor attacking the wave of corporate takeovers.

Meanwhile, Jesse Jackson, who has fallen far behind Dukakis in the race for the Democratic presidential nomination, said both Bush and Dukakis would continue Reagan's faulty economic policies.Jackson, speaking at a downtown Cleveland rally sponsored by 9 to 5, the National Association for Working Women, refused to concede the race to Dukakis, pointing to the 1984 Ohio primary where Gary Hart defeated Walter Mondale after Mondale won the big New York and Pennsylvania primaries.

"Ohio, you can make a big judgment on this coming Tuesday," Jackson said. "Mondale won New York and Pennsylvania. Ohio made an independent judgment."

He added, "Shall we sustain Reaganomics? That's what Bush says. Shall we manage Reaganomics efficiently? That's what Dukakis says. Shall we reverse Reaganomics? That's what I say."

Dukakis and Jackson campaigned in Ohio, where 159 delegates are at stake in next Tuesday's primary. Another 95 Democratic delegates are at stake Tuesday in the Indiana and District of Columbia primaries.

Bush, who will sew up the Republican nomination with his expected victories in those primaries Tuesday, toured a Magnavox Corp. defense electronics plant in Fort Wayne, Ind., and again attacked the trade bill that Congress passed and President Reagan plans to veto next week.

"We can compete," Bush said. "We don't need to look elsewhere, we look right here at home."

Bush's opposition to the bill, like Reagan's is mainly due to the provision requiring companies with at least 100 workers to give 60 daysnotice of plant closings or mass layoffs.

"I'm against the (plant closing) provision and for plant openings," he said. "We want to emphasize plant openings."

Dukakis, speaking to about 140 labor leaders in Columbus, Ohio, sharply criticized the administration for fostering anti-competitive business practices.

"If we're serious about winning the battle for our economic future, we've got to get control of the merger and acquisition binge that's gobbling up our capital, destroying competition and creating billions in profits for a few, without creating a single new job for American workers," Dukakis said in a 25-minute speech at an electrical workers union hall.

"Why are we putting up with this? Because we have a Labor Department and an NLRB (National Labor Relations Board) that won't stand up for the American worker," he said, "because we've got an attorney general who couldn't tell the difference between antitrust and antifreeze, and a Federal Trade Commission that seems to have forgotten that its job is to promote and encourage competition in the American marketplace."

Dukakis later told a Dayton rally the trade bill is a "good, solid, thoughtful" measure. He noted Massachusetts is the only state with a comprehensive plant closing law, which has helped to save thousands of jobs through its advance notice provision.

United Press International's count of committed and projected delegates shows Dukakis with 1,137.15 of the 2,081 delegate votes needed to win the nomination at July's convention in Atlanta. Some Democratic delegates cast fractional votes. Jackson has 784.20 votes in UPI's count.

On the Republican side, Bush has 1,092 votes, 47 short of the 1,139 he needs to secure the nomination.