CHRISTIAN KOCH, MICROCHEMICALS / SCIENCE PHOTO LIBRARY CHRISTIAN KOCH, MICROCHEMICALS / SCIENCE PHOTO LIBRARY
Pollen cell structures. Pollen grains are the male reproductive structures produced by flowering plants. They have a double wall (intine and exine) that encloses two structures called generative nuclei (purple). The exine (outer wall) includes spines or warts, and pores (holes). Here, the pollen grain is seen before (left) and after (right) it has landed on the stigma (female part of a flower). The pollen grain then extrudes a pollen tube (lower right) which includes a tube nucleus (black). The pollen nuclei then descend the pollen tube to fertilise the female reproductive cells in the ovule and form a zygote for the seed of a new plant.
Model release not required. Property release not required.