They had spoken by phone two weeks ago, a few days after Bryant asked to be traded, but this was a longer, more emotional conversation.
Buss wanted to appeal to the nine-time All-Star, reminding him that trades take time to develop and that winning remains the focus of the organization, but Bryant voiced concerns about the direction of the franchise and reiterated his demand to be traded, said a source with knowledge of the situation.
"That's the message that came out of it," the source said.
Team sources vehemently insisted there were no plans to trade Bryant, and they were still hopeful that a peaceful solution could be reached. Bryant and Buss are expected to resume their dialogue in the near future.
Bryant's displeasure has grown steadily since the Lakers were eliminated by Phoenix last month in the first round of the playoffs. The Lakers are 121-125 since reaching the NBA Finals in 2004, not including their first-round exits the last two seasons.
Last month, Bryant publicly requested that Jerry West return to the team's front office -- an unlikely scenario -- and urged General Manager Mitch Kupchak to make trades that would steer the team in a winning direction.
"I'm still frustrated," Bryant said at the time. "I'm waiting for them to make some changes."
The Lakers have contacted numerous teams, but there have not been any blockbuster deals yet -- by them or by any other team in the league.
Trade talks around the league are expected to heat up as the June 28 draft approaches and could continue into the free-agent period that begins July 1.
Bryant was vacationing in Spain and stopped by to see a practice session of his favorite soccer team, FC Barcelona, on Thursday. Buss had been in China since leaving the U.S. more than two weeks ago. He planned to travel to London before returning to Los Angeles, although it was unclear whether he went to Spain specifically to talk to Bryant.
"What they talked about and what went on between Kobe and Dr. Buss is private and will remain between the two of them," Lakers spokesman John Black said.
Bryant's agent, Rob Pelinka, did not return calls seeking comment.
Bryant, who will be 29 in August, has four years left on his contract, but he can void it in two years.
The two-time scoring champion, widely acknowledged as the game's most dynamic player, has the NBA's top-selling jersey and is a significant draw at Staples Center. The Lakers are very cognizant of his importance in driving ticket sales, as well as his effect on corporate sponsors.
Buss, who signed off on Bryant's seven-year, $136.4-million contract in July 2004, released a statement two weeks ago in which he said, "We will continue to pursue every avenue possible to improve our team with him as the cornerstone."