LOS ANGELES, Mar. 21 – Mary Brunner, a Charles Manson follower convicted of committing two armed robberies as part of a plan to free the murder cult leader, was sentenced Tuesday to two consecutive 10-year-to-life prison terms.

And in another court-room, the state Court of Appeal affirmed the first-degree murder conviction of Charles (Tex) Watson in the Tate-LaBianca slayings, but modified his sentence from the death penalty to life imprisonment.

Miss Brunner’s attorney, Howard Weitzman, had asked that she be given concurrent rather than consecutive sentences, arguing that she would be able to conduct herself “in a socially acceptable manner” after a period of time in custody.

Superior Judge Arthur Alarcon, however, invoked the more stringent sentence, noting that a psychiatrist testified during the trial to the “icy, callous determination” with which she regarded the possible necessity of killing several persons in order to free Manson.

She was convicted Feb. 21 with three other Manson “family” members on charges of having taken 143 rifles and $630 in cash from a Hawthorne surplus store on Aug. 21, 1971, and of having robbed a beer distributor in Covina of $2,600 eight days earlier.

Sentencing for her co-defendants, Kenneth Como, 33, Katherine (Gypsy) Share, 30, and Lawrence Bailey, 23, is scheduled for today, Thursday and Friday, in that order.

Alarcon also rejected a request from Como that he be married to Miss Share.

Watson, 26, was convicted Oct. 21. 1971, on seven counts of murder and one of conspiracy in the Tate-LaBianca slayings. At that time, he was sentenced to death.

He had been tried separately from Manson and the cult leader’s co-defendants, Susan Atkins, Patricia Krenwinkel and Leslie Van Houten, who also were convicted.

By WILLIAM FARR