Red Onion Cells

A thin section of a red onion (one layer beneath the outermost layer) was sandwiched between two layers of transparent packing tape.  Next, the onion was imaged with a FoldScope that was equipped with a low-magnification (140x) lens, LED light module, and iPhone (5) camera.  In this manner, it was possible to observe individual onion cells (see attached images).  Interestingly, many of these onion cells contained small circular structures that were located near the center of the cell.  I suspect that they may be nuclei.  An additional image of a candidate nuclei was acquired using a high-magnification (500x) lens.  In the future, it would be interesting to use a nuclei-specific stain in order to determine if the small circular structures are indeed nuclei.  Furthermore, it would be interesting to see if image quality might be increased by using only a single layer of transparent packing tape.


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3 Comments Add yours

  1. Manu Prakash says:

    Beautiful shot. I have never seen a red onion this red – at a cellular level. Where does that red color come from?

    Also; if you setup a short time lapse, you might see cytoplasmic streaming inside the onion cell. Really worth a try.


    1. pmooney3 says:

      If you look at a cross-section of a red onion, you will see that each individual layer within the onion has an outer portion that is pink/red in color. It was from this pink/red portion that a thin film was isolated and imaged. I found that red cells had a much improved contrast as compared to colorless cells.

  2. Manu says:

    @pmooney3: Thanks. That’s nice; next time I have to look at this layer. Also; for fresh onions – watch cytoplasmic streaming is a treat. Do give it a try – leave one of the “live” cells on a time lapse and see what happens. A beautiful story will unfold..


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