Pollen (microsporocyte, pollen mother cell or meiocyte), after meiotic division. After the formation of the four microspores, which are contained by callose walls, the development of the pollen grain walls begins. The callose wall is broken down by an enzyme called callase and the freed pollen grains grow in size and develop their characteristic shape and form a resistant outer wall called the exine and an inner wall called the intine. The exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive. In simultaneous microsporogenesis meiotic steps I and II are completed
The Grain of Wheat than the original. The image of the grain of wheat dying in the earth in order to grow and bear a harvest can be seen also as a metaphor of Jesus' own death and burial in the tomb and his resurrection. The Rev. William D. Oldland in his sermon "Unless a Grain of Wheat Falls into the Earth and Dies" said: The Apostle Paul also says: "What is sown in the earth is subject to decay, what rises is incorruptible" (1 Cor. 15:42). The Grain of Wheat Parable of the Grain of Wheat (Greek: ὁ κόκκος τοῦ σῑ́του; "ho kókkos