What is in Mr. Potato?

The Potato that we eat today originated  in the Andes of South America. We consume a storage organ of the plant called the tuber, which is a modified underground stem. All modern potatoes came from a single potato somewhere in modern Peru. I find this quite amazing. Up until about the late 1500s, the Potato wasn’t even part of the old world diet, but today it is the fourth most consumed food crop. The infamous Irish Potato famine resulted in a million deaths and a mass migration,causing the population of Ireland  to fall by about 25%! It has indeed changed the world, as much as Chinggiz Khan, the famed or dreaded Mongol.  I had more humble aspirations for the Potato. I wanted to study the tuber under the microscope with one of the DC micronauts; Aditi. The videos contain conversations, which I left behind as a record, so apologies in advance for inaccuracies in conversation. We sliced the potato with a hand microtome and made many thin slices. Here’s what we did with each slice.

  1. Viewing the unstained potato. Fascinating view of the modified chloroplast called the amyloplast, which makes starch and is rapidly converted to simpler sugar (energy) when the potato tuber sprouts new roots and shoots.

2. Potato tuber slice stained with iodine for about 30s and then washed with water. Starch reacts with iodine to give a nice dark purple color. It is amazing how the cell is filled with amyloplasts.

3, Potato tuber slice stained with methylene blue. Here the cell wall is well stained. It is interesting how you can barely see the nucleus and other organelles, while the amyloplast (which is a modified chloroplast) just inundates everything.

 

5. How does a cooked potato tuber look?

6. And what if we stain the cooked potato tuber with iodine?

 

The Potato cells are gigantic like the onion epidermis and make for some wonderful viewing.  If you haven’t done it before, you should give it a try.

 

-Aditi and Laks

 

 

 

 

 

 

 

 

4 Comments Add yours

  1. Manu Prakash says:

    This is the most hilarious (and inspiring) post I have read. This is absolutely fantastic. Great job team.. Aditi and Laks..

    cheers
    manu

  2. Manu says:

    Team @Laks and @Aditi: I just got the chance to watch all the videos. What inspiring videos.. I was on the edge of my seat.. specially when you first showed the starch granules. I had never seen them before; and now every time I will eat a potato; I will think about this post.

    Secondly, the discovery of the unfolded starch is wonderful. Now I understand why potato can actually be crunchy.. it’s just starch.

    It is so wonderful to hear you both talk; it was almost as if I was in the room with you. I will try this as well.

    Now I am hungry; and I would like to eat a Pani Puri.. yummy post.

    cheers
    manu

  3. laksiyer says:

    Thank you @Manu.. This is my (our) first time too. I am rediscovering the fascination with starch. Remember the dhobi using starch water to iron clothes in India? One of the things I want to see is amyloplasts in roots which are responsible for gravitropism.. Next investigation.

  4. Nataraj says:

    Cool, I have never known so much about potatoes before. This was very informative.

    Regards

    Nataraj

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