what are the meanings of the metaphor she uses of the pear tree the mule at the gate? What are their impact on the novel??

This chapter presents the story of Janie's childhood and of her sexual awakening. An important symbol that emerges in this chapter and continues to appear throughout the novel is the pear tree, which is a metaphor for Janie. It blossoms when Janie blooms, just when Janie has her sexual epiphany. The first sentence of the chapter is very important: "Janie saw her life like a great tree in leaf with the things suffered, things done and undone. Dawn and doom was in the branches." Janie's sexuality is always regarded by the author as natural.

http://www.gradesaver.com/their-eyes-were-watching-god/study-guide/section1/