Fire and Ice

There’s no need to call the fire department. This fiery column is merely the top of a flower’s pistil. The orange structures you see within the blue outline are called xylem.

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Fire and Ice

There’s no need to call the fire department. This fiery column is merely the top of a flower’s pistil. The orange structures you see within the blue outline are called xylem.

What am I looking at?

This is the top of a chemically cleared pistil from a thale-cress flower. You can see the stigma on top of the pistil in orange (1), with several round pollen grains stuck to it (2). The transparent blue portion below the stigma is known as the style (3); it contains xylem, also in orange (4), which distributes water to this part of the flower.

Biology in the background

In plants, xylem is part of the vascular system and helps distribute water throughout the plant. It is made of hollow cells connected end to end. The roots of a plant absorb water from the soil and the xylem transports that water throughout the plant. This water distribution system is critical in flowers because the development of seeds and fruit from flowers depends on an adequate water supply. In this image, you can see the characteristic spiral structure of the xylem (4). Xylem is also a major constituent of wood; in fact, the word is derived from the Greek word xylon, meaning wood.

This pistil is about 1.2 millimeters tall, or roughly 16 times the width of a human hair.

Technique

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