Pollen are the tectum and the foot layer, which is just above the intine. The tectum and foot layer are separated by a region called the columella, which is composed of strengthening rods. The outer wall is constructed with a resistant biopolymer called sporopollenin. Pollen apertures are regions of the pollen wall that may involve exine thinning or a significant reduction in exine thickness. They allow shrinking and swelling of the grain caused by changes in moisture content. Elongated apertures or furrows in the pollen grain are called colpi (singular: colpus) or sulci (singular: sulcus). Apertures that are more circular are
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