More than 100 striking teachers in one southern Mississippi school district were fired yesterday, and educators around the state were threatened with dismissal or loss of salary, as lawmakers scrambled for a pay package to end the first mass walkout by public employes in state history.

The firing of 136 striking teachers in Marion County was the first such action since the walkout began Feb. 25. The county school district's 163 teachers were sent certified letters late Thursday saying that those who did not show up for classes yesterday would be in violation of their state personnel contracts, which could then be declared null and void.

State Education Department spokesman Jack Lynch said that only a handful of teachers reported; about 20 called in sick, the rest defied the ultimatum. "They just said 'Forget it,' " Lynch said.

Marion County officials were telling the fired teachers that they can reapply for their jobs once the strike is settled.

The strike, over the issue of pay, has spread to more than one-third of the state's 154 school districts (yesterday was the first day that no new districts joined). It has sent more than 9,000 teachers onto picket lines and has brought early spring vacations to nearly 172,000 students. Mississippi teachers, with an average salary of $15,971, are the lowest-paid in the nation.

George Brown, a spokesman for the Mississippi Association of Educators in Jackson said he is telling teachers that if they "don't feel pretty secure, they'd better get back in there unless they have a pot of gold."

Brown said that emotions have reached fever pitch among the state's almost 25,000 classroom teachers, and that an informal statewide survey Thursday showed widespread support for the walkout despite the new threats.

Brown said the Marion County teachers, whose average salary is $15,568, "voted overwhelmingly to stay out" even after receiving notice that they would be fired. "I can't believe this -- and in Mississippi!" Brown said. "They are saying there's no way they're going back in, unless the legislature shows them something."

Meanwhile, the crisis atmosphere in Jackson has abated somewhat. With regular spring school vacations scheduled to begin Monday, state legislators went home without agreeing to a new teacher-pay plan; the state school superintendent left for a national convention in Dallas; and Lynch, the Education Department's chief spokesman on the strike, said, "I'm leaving town and going fishing."

Gov. Bill Allain (D) has threatened to veto any teacher pay package involving a tax increase, setting the stage for a legislative standoff.