Roy Mark Hofheinz rose from a radio disk jockey to Mayor of Houston and was the entrepreneur who conceived of the Astrodome. Mr. Hofheinz, a legislator at the age of 22, Harris County judge at 24 and two-term Mayor of Houston, was partly paralyzed by a stroke in May 1970. His strength impaired, he spent recent years confined to a wheelchair most of the time. He was alert through the 1970's and tried, with the help of four aides, to remain active. Monuments to his business skills include the world's first domed stadium, the Houston Astros baseball team and the Astroworld amusement park. In his later years, the Texan was for a time part owner of the Ringling Brothers-Barnum & Bailey Circus. Early Years of Struggle Mr. Hofheinz, the son of a laundry truck driver, was born in Beaumont, Tex. The family moved to Houston, 90 miles to the east. His father died when he was 15 and he began work early to help support his mother and himself. He attended Rice University, the University of Houston and Houston Law School, now South Texas College of Law. Mr. Hofheinz earned his law degree at the age of 19. Three years later, he sought and won a term in the Texas Legislature. At 24, he sought and won election as Harris County's chief executive officer, the county judge. In 1944, after losing a bid for re-election, he became a lawyer and businessman. In the process, he acquired part ownership in several radio and television stations, including Houston's KTRK-TV. He also bought a few oil wells and much land around what was to become one of the nation's most prosperous cities. In 1952, at the age of 40, he was elected Mayor of Houston. In 1960, Mr. Hofheinz proposed the world's first indoor stadium to facilitate major league sports in a city where intense heat, humidity and mosquitoes made most outdoor activity unattractive to fans. He persuaded residents of Harris County to vote bonds to finance the $31.6 million Astrodome and the world's first domed stadium opened in 1965 with Mr. Hofheinz's holding a 40-year lease. Aside from indoor baseball and football, the Astrodome inaugurated the era of the plush skybox, a Hofheinz idea that made profitable use of the space above the regular stadium seating area. Mr. Hofheinz also helped innovate artificial turf, first known as Astroturf, because the stadium's skylighted roof provided inadequate sunlight for grass. Mr. Hofheinz leaves his second wife, Mary Frances Gougenheim, his secretary, whom he married after his first wife, Irene, died in 1966; his daughter, Dene Hofheinz Mann; his sons, Fred, a former mayor of Houston, and Roy Mark Hofheinz Jr., a Harvard professor.