Pollen in Its Place

What am I looking at?

The blue structure is the stigma (1), the very tip of the pistil of this thale-cress flower. The orange dots are pollen grains (2) that are stuck to the stigma.

Biology in the background

This image shows the very beginning of the process that flowering plants use to reproduce. Pollen is produced by the anther of a flower and then is spread far and wide by wind or pollinators like insects, birds, bats, and other animals. The pollen grains travel until they encounter another flower of the same species. When they do, they stick to the top part of the pistil, known as the stigma. Once stuck there, the pollen grains germinate, each one forming a pollen tube to carry the plant’s genetic material down the pistil and into the ovary, where it merges with an ovule, leading to seed production.

The pollen grains from this plant are about 25 micrometers across, or roughly three times smaller than the width of a human hair. The pistil of this flower is about 0.8 millimeters long, or roughly 25 times smaller than the width of a human thumbnail.

Technique

This image was created by chemically clearing the pistil tissue and then imaging the resulting sample with confocal microscopy.