Poland's military authorities today took two tough moves that indicate they are significantly escalating their actions against dissidents.

The authorities announced that four leading dissidents had been charged with attempting to overthrow the state by force, and for the first time they formally ruled out talks with the elected leadership of the suspended Solidarity trade union.

The moves were interpreted by Polish and foreign analysts as a major escalation against Solidarity and its dissident advisers following nationwide antigovernment demonstrations earlier this week. After quashing protests in 34 of Poland's 49 provinces, the martial-law government now evidently feels strong enough to attempt the dismantling of all organized political opposition.

The government press spokesman, Jerzy Urban, also revealed that a worker in the southwestern city of Wroclaw died yesterday after being shot in the chest during street disturbances Tuesday. He said an investigation was being launched into the incident, which followed the fatal shooting by police of at least two demonstrators in the nearby copper-mining town of Lubin.

The ostensible target of the political trials now being prepared by the martial-law authorities is the dissident Committee for Social Self-Defense (KOR), which pioneered the idea of organized massive resistance in the late 1970s. But the wider purpose seems to be to prevent the formation of any future alliance between workers and dissident intellectuals such as that which gave birth to Solidarity.

At a press conference here for foreign correspondents, Urban said that the military prosecutor had ordered the arrest of four dissidents interned under martial-law regulations in effect since December. They include two of KOR's best-known leaders, Jacek Kuron and Adam Michnik.

Kuron, 48, was regarded as the organizational leader behind KOR and acted as a senior adviser to Solidarity leader Lech Walesa. He helped found KOR in September 1976 with the aim of protecting workers persecuted by the authorities and turned it into the most influential of dissident groups in Eastern Europe. KOR formally disbanded a year ago on the grounds that, with the rise of Solidarity, it had served its purpose.

Also charged, under Article 123 of the Polish Penal Code, were two other KOR members, Jan Litynski and Henryk Wujec, both of whom worked on underground publications before and after the labor unrest of August 1980. Warrants have been issued for several other KOR members who are in hiding.

Article 123 covers conspiracy "to overthrow the political system by force" and carries a maximum sentence of death and a minimum of five years imprisonment.

A former KOR spokeswoman, Anka Kowalska, said that the charges against the dissidents were absurd and unprovable.

"We never planned or contemplated the use of force, violence or terror," she said. "Peaceful methods formed the basis of KOR's ideology--and this was stated on numerous occasions. This was how we wanted to shape society's consciousness."

News of the moves against KOR was combined with a dramatic hardening in the government's position on negotiating with Solidarity following the riots earlier this week. Urban described attempted demonstrations on Aug. 31, the second anniversary of the Gdansk agreement that legalized free trade unions, as "a funeral march for Solidarity extremists" under which heading he apparently included Solidarity's entire elected leadership.

"There will be no discussions with the instigators of these incidents," he added. "To implement national accord, we shall address society and the masses of Solidarity members directly without using Solidarity's former leaders as an intermediary."

Asked whether he was also precluding negotiations with Walesa, he replied that the Solidarity leader had not shown any willingness to talk with the government. Unless he changed his "negative attitude" displayed during nearly nine months in internment, there could be no talks with him, Urban said.

Until now, one factor restraining the authorities from banning Solidarity has been the fear of triggering off a wave of strikes and demonstrations by workers. Last Tuesday's demonstrations appear to have provided the government with an opportunity for cracking down now.

The government evidently feels more confident of its ability to counter organized opposition now that it has shown it can handle street protests by deploying large numbers of police.

The official propaganda line is now to make no secret of the scale of this week's unrest in order to drive home the message that the security forces were nevertheless quite capable of dealing with it. Urban revealed that protests of one sort or another occurred in 54 different localities with the cities of Wroclaw and Krakow the worst affected.

He said that more than 1,800 people had already been punished for taking part in the demonstrations out of a total of 4,050 arrested. Magistrates' courts had fined 1,667 people and sentenced another 137 to prison.

Urban said that the southwestern town of Lubin was now calm after three successive days of rioting.