Buoyed by generous gifts from associates of Lyndon B. Johnson and the wealthy Reynolds Metals Co. family, two canidates in Virginia's Democratic primary for lieutenant governor today disclosed that they have already spent nearly $500,000 in their race for part-time job that pays $10,500 a year.

Today's disclosures by Charles S. (Chuck) Robb, the late President's son-in-law, and State Del. Richard S. (Major) Reynolds III, a member of the Reynolds Metals family, are certain to make the June 14 primary the most costly ever for the state's No. 2 office.

Del. Ira M. Lechner (D-Arlington), the third canidate in the race for the largely ceremonial job, announced he has raised only $91,709.96 and scoffed at Robb and Reynolds for their expensive campaigns. "When I said these two poor boys are going to throw about a million dollars at me, I wasn't wrong," Lechner said in an interview.

To make matters worse for Lechner, he confirmed today that his campaign staff got kicked out of a surban Richmond apartment last week in a zoning dispute.

Robb, a McLean lawyer, filed a campaign finance report disclosing that he had raised $114,698.23 - including a $10,000 gift from Lady Bird Johnson, his Mother-in-law - and has borrowed another $120,988 for his campaign. A spokesman said Robb put up his home and personal holdings to barrow $100,000 for 90 days from The United Virginia Bank - National in Northern Virginia to pay for an extensive television ad campaign.

Reynolds, a freshman legislator who is hoping to win the job once held by his older brother, the late J. Sergeant Reynolds, told a news conference he now expects to spend "between $350,000 and $400,000" on his campaign. Between 80 per cent and 90 per cent of that amount will come from the Reynolds family, he said.

Reynolds put his net worth at about $1.1 million and defended "as a practical matter" his decision to depend heavily on his relatives for campaign funds. ". . . When one is from what is presumed to be a well-to-do family, it is more difficult to raise funds," he said.

Of $295,273 Reynolds said he had received in contibutions by May 10, $221,000 came from his father, R. S. Reynolds Jr., a retired Reynolds executive, and his mother, Virginia S. Reynolds. The candidate gave $45,000 to his campaign and borrowed another $40,000. Other relatives chipped in $8,900 and Rep. Stephen L. Neal (D-N.C.) also a relative, gave $200.

In financial reports that yere required by state law to be filed today with Virginia election officials, it appeared that Robb had had the most success of the candidates for lieutenant governor in raising funds. Fund-raising parties held at his McLean home have attracted many major political figures and his report listing contributors read like a "who's who" of the Johnson administration.

Robb's contributors include Sen. Lloyd M. Bentsen Jr. (D-Texas), $1,000; Sen. Allen Bible (D-Nev.), $100; Liz Carpenter, former press secretary to Mrs Johnson, $250; George E. Christian, former White House press secretary, $100; Clarke Clifford, former defense secretary, $500; Washington lawyer Thomas G. Corcoran, $250; and Nancy Dickerson, former broadcast personality and Washington socialite, $250.

Former Supreme Court Justice Abe and Mrs. Fortas contributed $250; former Agriculture Secretary Orville L. Freeman, $100; Dr. Armand Hammer, head of Occidential Petroleum Corp. of Los Angeles, $250; former Russian ambassador and speical diplomat Averell Harriman, $250; Rep. J.J. Pickle (D-Tex.), $250; and Wolf Trap Farm founder Catherine SHouse, $100.

Art benefactor Joseph H. Hirshhorn of New York gave $250; Mary Lasker, a New York City philanthropist, $1,000; former Democratic Party Chairman Robert Strauss, $250; former U.S. Joseph D. Tydings of Maryland, $250; Jack Valenti, a former Johnson aide, $500; and Redskins football owner Edward Bennett Williams, $250.

Lew R. Wasserman of Beverly hills, Calif, president of the Music Corp. of America, gave $2,500; House Majority Leader Jim Wright (D-Texas), $100; former Labor Secretary Stewart L. Udall and White House consumer adviser Estehr Peterson, $50 a piece.

In comparison to the money Rynolds and RObb reported receiving from their relatives, Lechner listed a $50 donation from his mother and a $600 loan from his wife that has been repaid.

Most of Lechners contributions came in the form of small donations from Northern Virginians and from Virginia and Washington-area labor unions.

In the four-way race for the Democratic nomination for Attorney General, State Del. Edward E. Land of Richmond reported spending the most money - $78,047 - of the three candidates who filed their reports today. Contributions to Lanes campaign accounted for about half of the $80,914.17 he has raised. The remainder of the funds, $40,139.84 was borrowed from various sources, including $24,000 from Lane's Richmond law firm.

Del. John L. Melnick (D-Arlington) borrowed $25,000 for his campaign, but his actual donations of $42,553.51 surpassed Lane who generally had been thought to have had the most success raising money in the race.

McLean lawyer John T. Schell reported gifts totaling $24,570 and spending $25,158 in his race. Del. Erwin S. (Shad) Solomon of Bath County, the fourth candidate in the race, did not have his report in the state elections board office today. The reports will be considered filed on time if postmarked by midnight tonight, a board spokeswoman said.

Republican candidates for statewide office are selected by convention and will not have to file any expense reports with the state until 30 days before the Nov. 8 election.