Every time I make fajitas, I cut into bell and chili peppers and notice how hollow they are. I always think to myself: what is the gas inside this pepper, and how does it get there?
Perhaps Capsicum peppers are porous. I did a little kitchen experiment to try to find out. (I'm afraid I don't know much about biology, so this "experiment" is likely to be flawed in at least one basic way, but I figured I should at least try to figure it out myself before asking.) Here's what I did:
I filled a small container with water and submerged an uncut Anaheim pepper. It was quite buoyant! I put the lid on the container so it would stay submerged. It didn't seem to become any less buoyant, and its interior didn't seem to fill up with water. No bubbles emerged from the pepper, as least as far as I could tell.
So air doesn't seem to easily pass in or out of the pepper. And of course they don't grow around air, so how does the gas get in?
Here are my guesses:
- The fruit is porous to air, but the holes are small enough that, in my experiment, they were sealed by the surface tension of the water.
- The fruit isn't porous to air when fully grown, but it is porous to air while it's still developing.
- The fruit does some amount of photosynthesis, and the air is waste oxygen.