Spot on tangerine skin: Bio60_2019

Spot on tangerine skin
Orange/ ripe part of tangerine skin
Green/ not ripe part of tangerine skin

When picking tangerines on the Stanford campus I noticed That some of the fruits had a few little black spots on their skin. I wondered what these spots were and decided to look at them with my foldscope. I picked and saved a tangerine with a spot until I had time to prepare a slide and look at very thin cross sections of the skin. I used a very razor to get thin enough sections. Shown in the pictures are the black spot, skin of the tangerine that was orange (ripe), and a part that appeared green (not ripe). What surprised me most was the shape of the spot. It is not round or uniform which makes me think it is some type of microorganism. Could it be related to the fungus that causes black spot in roses? I doubt it because The spot was very small, 2 mm maximum. But its was not dirt because it did not rub off and was noticed when the tangerine was still on the tree. In addition, I show the difference Between ripe and not ripe tangerine skin. The main difference I notice is that the cell outlines are clearer in the ripe skin picture. There may be a better-defined pattern in ripe tangerine skin.

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