Jiang Qing, the disgraced widow of Mao Tse-Tung, appeared in court today and was said to have replied "I don't know" to charges that she tried to discredit Deng Xiaoping, now China's foremost leader, and the late premier Chou En-lai.

Knowledgeable sources said the 67-year-old leader of the so-called "Gang of Four" took the stand for more than an hour.She reportedly was questioned about only one of the charges against her and the other prominent leaders of the Cultural Revolution.

The official Xinhua news agency said Jiang Qing was called to appear by the First Tribunal of the special court that is hearing the case against the gang. It marked her first appearance in court since the indictment against the radical leaders was read out at the opening of the trial last week.

The news agency said the court was investigating "facts about the charges that Jiang Quing, a principal defendant of the Lin Biao and Jiang Quing counterrevolutionary cliques, had plotted to bring before Chairman Mao Tse-tung false accusations against Chou En-lai and Deng Xiaoping."

The sources said she repeatedly replied "I don't know" when asked about the testimony of a codefendant, Wang Hongwen, that she dispatched him to Mao to tell her husband that Chou and Deng had been engaged in a conspiracy against him.

Last night, Wang and another leader of the Cultural Revolution who helped engineer the 1976 ouster and humiliation of Deng made humble confessions in a nationwide television broadcast. But they shifted blame for the "frame-up" to Mao's widow.

The fumbling, meek testimony yesterday of the two once-powerful radicals who rose to the Politburo in 1969 recalled similar scenes during the Cultural Revolution when scores of Chinese officials, including Deng, were forced to make "self-criticisms."

The fact that the first two defendants called to testify at the Gang of Four trial admitted persecuting Deng -- known during the radicals' heyday as a "counterrevolutionary double-dealer" -- shows how much China's leadership has changed since the four were arrested in late 1976.

The passage of time also was reflected yesterday in the physical appearances of the defendants: Yao Wenyuan, 49, the Cultural Revolution's proud publicist, now puffy-faced and sputtering, and Wang, 45, the dashing textile worker from Shanghai and zealous archetype of the Cultural Revolution, his head now shaven and bowed.

The two men and Jiang Qing are being tried along with two other erstwhile radicals on charges of persecuting and framing thousands of officials and plotting resurrection. In a sense, the Cultural Revolution they ran from 1966 to 1976 is on trial.

In a second courtroom, five generals once allied with the late defense minister Lin Biao are standing trial on charges of plotting to assassinate Mao in 1971 and stage an armed coup. Lin, named Mao's heir apparent two years earlier, reportedly died in an airplane crash trying to flee the country after the unsuccessful mission.

Although the trials officially are described as open to the public, only those with invitations can attend. For the rest of the curious nation, selected portions of the previous day's events are broadcast on television and radio each night.

In last night's televised version, Yao and Wang confessed to participating in a two-year drive to discredit Deng and prevent him from becoming the first vice premier of China. They succeeded, and Mao ordered Deng to be purged and criticized in October 1976.

Appearing separately before the panel of 35 judges, both defendants said they were following the orders of Jiang Qing, the onetime movie actress-turned-radical who reportedly decided to head off Deng after he began regaining political strength in 1974 and trying to blunt China's leftist policies.

Efforts to derail Deng intensified in October 1974, China's television audience was told. Wang then visited Mao at his home in Changsha and suggested that Deng and other moderates were planning to grab power in Peking.

It was at this meeting, according to testimony, that Wang said, "The atmosphere in Peking is like that of Lushan" -- a reference to a 1970 people's congress in the Lushan highlands at which Lin Biao tried to have himself named head of state.

At another point in his meeting with Mao, Wang noted that premier Chou was seriously ill, but continued talks "late in the night" with Deng and other opponents of the radical Politburo members, according to testimony. In Chinese jargon, late-night discussions imply conspiracy.