ATLANTA (AP) — With hours left before her execution Monday for her husband's murder, the only woman on Georgia's death row asked a state board to "bestow mercy" and appealed to the U.S. Supreme Court for a delay.

Earlier Monday, a federal appeals court in Atlanta rejected her lawyers' request to halt her execution on the grounds that Georgia's lethal injection procedures aren't transparent enough to allow a legal challenge.

Kelly Renee Gissendaner, 46, is scheduled to receive an injection of pentobarbital at 7 p.m. Monday at the state prison in Jackson, for the February 1997 murder of her husband, Douglas Gissendaner.

Prosecutors said she plotted his stabbing death with her boyfriend, Gregory Owen. Owen pleaded guilty and is serving a life sentence; his first possibility of parole will come in eight years, her lawyers said.

Gissendaner would be the first woman executed in Georgia since 1945 and only the 16th woman put to death nationwide since the Supreme Court allowed the death penalty to resume in 1976.

The parole board is the only entity in Georgia authorized to commute a death sentence.

Gissendaner's lawyers note that the parole board already heard from many people testifying about Gissendaner's faith and remorse at a hearing last week before denying her clemency.

But, her lawyers argue, the board did not hear from many Department of Corrections employees whose perspective "would have left no doubt that a grant of clemency is supported in this case."

The most important witness the board did not hear from is Kathy Seabolt, who served as her warden for six years, first at Metro State Prison and then at Lee Arrendale State Prison. Seabolt could testify that former parole board chair James Donald promised Gissendaner would receive clemency, her lawyers wrote.

Each time the topic came up in conversations between Donald and Seabolt, "Donald reiterated his statement that Ms. Gissendaner did not need to worry about clemency as it was a foregone conclusion," they wrote.

Gissendaner's lawyers also urged the parole board to subpoena some other corrections employees so they can testify without fear of retaliation.

Although department rules allow employees to speak to lawyers for capital clemency proceedings, the reality is less clear, Gissendaner's lawyers wrote. Some employees had said they would testify and provide written statements on Gissendaner's behalf, but changed their minds after getting a memo from the new warden, who succeeded Seabolt last year.

"Under no circumstances are you to discuss this with people outside the institution. Staff should also be careful what is said to other inmates and personal feelings are to be suppressed," Kathleen Kennedy wrote on Jan. 29 as she notified staff of the likelihood of the upcoming execution.

Gissendaner's lawyers also urged the board to consider that before trial, she had been offered the same plea deal as Owen — life in prison with an agreement not to seek parole for 25 years.

"At one time, therefore, all the parties involved in the case thought a sentence less than death was appropriate for Ms. Gissendaner," her lawyers wrote.

Owen, who is the one who stabbed Douglas Gissendaner to death, took the deal and testified for the prosecution. Gissendaner balked at the parole agreement and took her lawyer's advice to go to trial.

The parole board has granted clemency before in cases involving disproportionate sentences for co-defendants, her lawyers wrote.

"In fact, this Board has on at least four occasions in the past commuted a death sentence of a co-defendant who was not the actual killer of the victim," the lawyers wrote.

Douglas Gissendaner's parents and sisters want her to be executed, but two of Kelly and Douglas' three children have asked the parole board to spare her life, the lawyers wrote.

In statements submitted with her clemency application, Kayla and Dakota Gissendaner describe a journey from bitterness and anger to forgiveness; finally they have a meaningful relationship with their mother.

"We also believe that Kelly's death will not restore them or make them whole," Gissendaner's lawyers wrote of the entire Gissendaner family.

Gissendaner was originally set to be executed last Wednesday, but the Department of Corrections postponed it due to a winter weather report.