A solitary hand was raised in the chamber of Poland's national assembly, the Sejm, last night when the marshal asked whether there was anybody opposed to the martial law decrees already implemented by the military government.

Six more hands went up when the marshal, standing beneath a giant Polish flag, asked if there were any abstentions. By contrast, a forest of more than 400 hands went up in support of the prime minister, Gen. Wojciech Jaruzelski, and his Military Council for National Salvation.

After 16 months in which it tried to shake off the reputation of being "a rubber-stamp parliament," the Polish Sejm is once again under firm Communist Party control.

This week's parliamentary session was called to legitimize the suspension of many basic civil liberties in Poland and the internment of thousands of activists of the independent trade union Solidarity. Opening his speech with the words of the national anthem, "Poland Has Not Perished," Jaruzelski presented himself as a man struggling to preserve national institutions such as the Sejm rather than crush them.

In fact, the two-day meeting is likely to mark the start of a new rift between parliament and people, just as the gap was beginning to close. The determination of the authorities to stage-manage the proceedings was reflected in the suspension of live television transmissions of the debates. Instead, edited highlights were shown later.

But, for all the careful preparations, there was still a sense of occasion in the air as the deputies gathered in the semicircular, pillared chamber for the first time since martial law was declared Dec. 13. Together with the Roman Catholic church, the Sejm has long been regarded as the repository of Poland's national sovereignty: theoretically it can act as it pleases.

Like Poland itself, the Sejm has veered between total compliance and total defiance during its existence, which dates back five centuries. Examples of both attitudes fill the textbooks of every Polish schoolchild.

As yesterday's session began, some onlookers in the public gallery recalled the behavior of Deputy Tadeusz Rejtan who--in 1773--protested attempts to legalize the first partition of Poland by Russia, Germany and Austria. Shouting "over my dead body," he ripped the clothes from his chest and blocked the entrance to the chamber, thereby preventing his embarrassed colleagues from entering.

Rejtan managed to hold up the debate for 38 hours before he finally withdrew. He thus earned a special place in Polish history, which likes to honor courageous individuals who hold out against hopeless odds--even if they eventually lose. The Sejm eventually legalized the partition.

The question on everybody's minds yesterday was: Would any of the present deputies follow Rejtan's example?

There was, of course, no chance of the martial law decrees being voted down. The present Sejm was elected in March 1980--well before Solidarity's emergence--with the Communist Party and its allies winning 90 percent of the seats. All could be counted on to support the government.

Interest, therefore, centered on the reactions of the 50 or so "nonparty," but carefully screened, deputies.

Over the weekend, a palace coup within the Pax group of progovernment Catholics had resulted in the removal as leader of Ryszard Reiff, the only member of the State Council to vote against the introduction of martial law in the early morning of Dec. 13. Reiff did not attend the Sejm session.

Speeches critical of aspects of martial law were made by the leader of the five-man Znak, a group of independent Catholic deputies, Janusz Zablocki, and a well-known journalist, Karol Malczuzynski.

Radio Warsaw broadcast a long report of Malczuzynski's critical comments Tuesday, including his condemnation of loyalty oaths as "morally and politically detrimental," the Associated Press reported. It was not known why the state-run radio gave so much attention to Malczuzynski.

When it came to the vote, these critics abstained.

The opposing vote was registered by Romuald Bukowski, a painter from Gdansk who has frequently spoken out in support of Solidarity over the past year. A distinguished-looking figure in a bow tie, Bukowski walked out of the chamber during a speech by a Communist writer who ridiculed the critics of martial law.

The writer, Janusz Przymanowski, compared Solidarity to "the hordes of Genghis Khan" who, he said, had beheaded everyone higher than the wheel of a horsecart.

For a foreign journalist looking down from the visitors' gallery, the debate reflected Poland's own inner ironies: an overwhelmingly Catholic nation with rich parliamentary traditions in which Communists have a monopoly of political power. On top of all this, there was evidence of the fact that the country is now being run by the Army.

Dressed in the uniform of a five-star general, Jaruzelski sat stiff and erect in the front row of the government benches, behind him an assortment of government ministers and Army officers.

The marshal brought the house to order by banging his rod on the floor following the old tradition. Communist deputies cited approvingly passages from Jaruzelski's speech and lauded the virtues of the uniform and military discipline. The Catholics quoted from the sermons of the primate of Poland, Archbishop Jozef Glemp.

Like a true parliamentarian, the prime minister and martial law chief listened carefully to all the speeches which were sprinkled with elaborate parliamentary rhetoric.

At the end of it all, Army officers, ministers and foreign journalists all mingled in the line at the coatroom. The former Communist Party leader, Stanislaw Kania, smiled benignly as he put on a homburg and shook hands with old friends.