De-etiolation

By Jay Presley and Laura LeMay

This project was centered on the de-etiolation of bean (dicot) and wheat (monocot) plants. De-etiolation is the process by which plants change or convert their etioplasts, plastids, within its cells into chloroplasts. Etiolated plants are plants that have been growing in complete darkness and are usually long, skinny and white. They express these traits because they are focusing their energy towards growing up against gravity and towards a light source. We have demonstrated the process of de-etiolation by growing wheat and bean plants in the dark for over 2 weeks, exposing the plants to light for a few days, and recording the visual changes of the plants to light by means of a time lapse video. Both types of seeds were planted at the same time and placed in the dark. The recording of the time lapse video begins when the plants were taken out of the darkness. The video shows the changes that take place in the plants at a rate that is more noticeable to the naked eye. De-etiolation can be a quick process so the video will allow us to slow down and observe this process.

The de-etiolation of the monocot and dicot showed interesting results. The wheat (monocot) showed slight greening of the stems but not much in the form of standing upright towards the light. This was primarily due to how long the wheat plants were and that they were unable support their own weight. In order to avoid this, younger and shorter wheat plants could be used that are still standing upright. However, some of the stems did show the presence of de-etiolation by the manufacturing and activity of chloroplasts giving them a green color. The dicot bean (dicot) plants had more pronounced changes from de-etiolation. The leaves turned completely green, and even moved/rotated in the direction of the light, showing signs of the plant’s response to blue light. The stems of the bean plants did change slightly to a greener color, but the lack of significant change could be due to the short amount of time that was given for this process to occur. The overall results were as expected in that the color of the plants changed from white to green, providing evidence that the chloroplasts inside the plants were finally able to become active and photosynthesize.