Ghaderzadeh, son of Sakineh Mohammadi Ashtiani, was himself released on bail on December 12.
His meeting with the media was arranged by the provincial justice department at a guesthouse belonging to a government welfare organisation.
Mohammadi Ashtiani also made a camera appearance for journalists on Saturday in what officials termed an "out of prison visit" with family. Journalists were shown a film clip in which she was seen at the guesthouse eating dinner and chatting quietly with her son.
She did not make any comments and her grown-up daughter who was also present appeared to be trying to avoid the cameras.
Mohammadi Ashtiani, a 43-year-old mother of two, was sentenced to death by two different courts in Tabriz in separate trials in 2006.
Her sentence to hang for her involvement in the murder of her husband was commuted to a 10-year jail term by an appeals court in 2007.
But a second sentence to death by stoning on charges of adultery levelled over several relationships, notably with the man convicted of her husband's murder, was upheld by another appeals court the same year.
Her stoning sentence triggered an outcry in the West and her son on Saturday pleaded that her execution be stayed.
"My mother has been sentenced to stoning... I want her death sentence to be dropped. This is my request," said Ghaderzadeh, adding that he hoped the sentence would be stayed as Iran's former judiciary chief Ayatollah Mahmoud Hashemi Shahrudi had backed the suspension of such sentences.
Ghaderzadeh, who was himself arrested by authorities on October 3 for speaking to two German journalists, is now out on bail of around 40,000 dollars posted by a relative. The two German journalists are still in custody.
Ghaderzadeh said he made his mother's case "controversial" in order to save her but acknowledged that the plan had backfired.
"I thought if the case becomes controversial, she would be freed. But it did not happen," the bearded youngster wearing spectacles said in Persian with a heavy Azeri accent.
"I planned this myself and searched on the Internet and found Mina Ahadi who introduced me to (Mohammad) Mostafaie," he said, referring to a Germany-based activist who has championed his mother's case.
Mostafaie, who was the first lawyer of Mohammadi Ashtiani, has now left Iran. Ahadi raised the alarm in November over what she said was Mohammadi Ashtiani's imminent execution.
Ghaderzadeh criticised Mostafaie, the two German journalists and the second lawyer Javid Houtan Kian, who too is in custody, saying the group had "worsened" his mother's case.
"He (Mostafaie) charged 20 million rials (2,000 dollars) and then escaped without even meeting me or my mother," Ghaderzadeh said, disputing the lawyer's remarks that his father was a drug addict and used to force Mohammadi Ashtiani into prostitution.
"What Mostafaie recently said that my father was a drug addict is a lie. He has made this up," said Ghaderzadeh, accusing the lawyer of using the case to seek asylum outside Iran.
"I want to complain against Ahadi because she abused the case, Mostafaie for his false interviews, Houtan Kian for his advice to make the case more controversial and the two German reporters who entered the country as tourists," he said, adding that he made a "mistake" in talking to them.
Ghaderzadeh also criticised Taheri and said it was "desperation" in the initial days that made his family grant clemency to his mother's lover, which led to his release.
"The question is why is Taheri free?," the youngster said.
"He misused our desperation at that time to get our approval, but I will get Issa even if I have to study law." Under the Iranian penal code, a murder victim's family can offer clemency to the convict.
Iran's English-language Press TV aired footage of Mohammadi Ashtiani last month in what it said was a re-enactment of the murder of her husband.
The report also included interviews with Mohammadi Ashtiani, her son Sajjad and lawyer Houtan Kian, and also accused Ahadi of seeking to politicise the case in the Western media with the aim of undermining the Islamic republic.