Stacking Up Eggs

What am I looking at?

This is a cross section of the pistil of a thale-cress flower. You can see pollen grains attached to the top of the pistil, which is called the stigma (1). In this image, the pollen grains are starting to send pollen tubes (2) down to the ovary, which contains the ovules (3). Click on the right arrow to see a related image — a magnified view of the stigma and the uppermost ovules contained within the ovary.

Biology in the background

The pistil of a flower contains ovules, which are a plant’s version of eggs in an animal. Once pollen germinates, it sends pollen tubes down through the pistil to fertilize the ovules below. These fertilized ovules eventually become seeds. A pistil is composed of three main parts: on top the stigma, which receives pollen from another flower of the same species; then the style, through which the pollen tubes grow to reach the ovules; and finally the ovary, which contains the ovules and is the final destination of the pollen tubes.

These ovules are about 100 micrometers across, or just slightly bigger than the width of a human hair.

Technique

These images were created using confocal microscopy.