The pomegranate.
Persephone had ate the pomegranate in the Underworld; so had to return to the Underworld a part of every year.
Kidnapping, most assume, Persephone did the eating of the food of the underworld part, which stuck her in the Underworld; guaranteeing she could never fully return to the world above: but she had to return thus becoming the goddess of spring.
Persephone's tragic flaw is her naivety and curiosity. When she was kidnapped by Hades, her curiosity led her to eat pomegranate seeds, binding her to the underworld for part of the year. This cycle of her descent and return to the underworld represents the changing seasons.
In Greek mythology, winter was caused by Demeter's grief over Persephone's return to the underworld. Her daughter Persephone was kidnapped by Hades and ate pomegranate seeds, forcing her to return to the underworld for part of each year. As Demeter grieved over her daughter, she neglected the crops, causing them to wilt.
In Greco-Roman mythology, Pluto was the king of the Underworld. He married Persephone and only allowed her to return to earth for part of the year.
Because while in the Underworld during her first stay with Hades she ate some pomegranate seeds. Eating them bound her to the Underworld, and she must return to it for half of the year, and is able to be with her mother and the living for the other half of the year.
Persephone would have to spend a part of the year in the Underworld with Hades.
Persephone would have to stay in the Underworld for a part of the year.
The ancieant myth about Persephone and Hades states that any living thing that eats food from the underworld must remain there for all time. Perssphone did eat six pomigranet seeds however, and therefore must spend six months of every year in the underworld. This myth was used by the Greeks and Romans to explain winter (Persephone was the goddess of spring and growing things)
She lived part of the year in the underworld with her husband Hades.
The most popular is in which Hades asks Zeus for Persephone's hand in marriage and is granted it, while Demeter does not know and when Persephone is taken he offers her the pomegranate to eat in the Underworld. Which she does, thus she can't leave the Underworld save for part of the year. Demeter has been searching for her daughter, and finds out where Persephone is, and demands her return; when Zeus and Hades argue that Persephone must stay in the Underworld for a portion of time; Demeter lets the world feel her wraith in the first winter.
Persephone refused to eat anything when she was first taken to the Underworld, out of protest. But when she was offered the pomegranate seeds she was very hungry. She only a few, but in eating them it tied her to the Underworld, forcing her to return for half of the year.