Responding to the widening disparity between U.S. and German interest rates, the dollar yesterday plunged to an all-time low against the German mark before recovering in response to coordinated intervention by the United States and many of its trading partners.

The dollar touched 1.4555 marks in European markets, just under the previous low point of 1.4630 marks on Dec. 10, 1990, finally closing in European trading at 1.4645. Later in New York, the dollar closed at 1.4635 marks, down 0.0045 marks from late Friday.

In New York yesterday, traders predicted that the dollar would resume its decline despite intervention by central banks in several nations, while in Washington, Treasury Secretary Nicholas F. Brady said that "the surprising thing" about the dollar's decline was that it hadn't gone further following last week's drop in U.S. interest rates and rise in German rates.

Those who closely monitor exchange markets said they expected central banks to continue to support the dollar during the next few days. They classified yesterday's intervention as "significant," rather than "massive," but still effective in preventing a free fall of the dollar.

The bulk of the dollar purchases reportedly came from the New York Federal Reserve Bank on behalf of the Treasury and from the German central bank. There was participation also from the central banks of Britain, France, Italy, Spain, Austria, Belgium and Canada.

"They {the central banks} are not trying to put a firm floor under the market," said one expert. "Their tactic is to slow the decline and to remind the world that the {Western industrial nations} can still show cooperation, even if their economic policies diverge."

At a news conference on the budget, Brady yesterday urged the Fed's Open Market Committee to go further with its new policy of easier money when it meets in Washington today and tomorrow.

"We still believe there's ample room for lower interest rates in this country," Brady said.

"The Fed has actually, in terms of money growth, been below their own targets, and some would question why that is an appropriate place to be during a downturn in the economy."

The Federal Reserve, in response to the report Friday by the Labor Department showing further deterioration in jobs, cut both the discount rate and the federal funds rate by one-half of a percentage point Friday, a day after Germany's central bank boosted its discount and another key rate.

The combined effect was to weaken the dollar because investors were handed an incentive to move funds out of the United States -- and dollar-denominated investments -- and into Germany for a higher return.

Financial market sources said that, given the American economy's weakness, the Fed is likely to respond to pressure for still lower interest rates, and that the dollar is likely to reflect a growing disparity between interest rates here and abroad.

C. Fred Bergsten, director of the Institute for International Economics, said, "There is no reason to resist dollar depreciation."

President Bush's budget message for fiscal 1992 yesterday credited a 12 percent depreciation in the dollar last year with helping to reduce the merchandise trade deficit to $102 billion.

Bergsten forecast that the dollar might decline another 10 percent against the mark, to about 1.30.

The dollar held its ground better against the Japanese yen, a relative stability that some experts said might be due to financial market fragility in Japan, along with some pressure on the government to lower interest rates. At the close yesterday in New York, the dollar was at 130.635 yen, down 0.865 from Friday.