What is the significance of “Mary Jane”?

Pecola buys Mary Jane candies, little sweets with wrappers that have a picture of a blonde and blue-eyed girl. When Pecola eats the candy, the moment is described like the Christian eucharist: the passage says that to eat the candy is to eat Mary Jane (like eating the body of Christ), a transformative act that somehow brings Pecola (in her own mind) one step closer to being Mary Jane.