Think of the water lily. It has air bladders under each leaf to keep it afloat. It has to pump gas in there, and I would guess that these are filled largely with CO2. I’ll be the first to admit I don’t know the exact biochemistry behind that, though.
Yes, it is, but at this point I’m taking my pearls and horse-water and going home.
Before you go, Darren Garrison, would you care to address how waterlilies create hollow flotation devices, or is your answer simply “human breeding”?
This is a simple question with a very, very complicated answer. Which makes it perfect for GQ. Makes it perfect for the Straight Dope. This kinda thing is Cecil’s bread and butter.
Wait… Malic Acid! It’s even part of the citric acid cycle! If I remember correctly, it can bind CO2. That’s gotta be part of the answer right there. A plant will store the CO2 caused by it’s respiration by sticking it to the Malic acid and then release it later. Most do that through the underside of leaves. stomata. Water Lilies! I knew there was something bouncing around in the back of my head with that. That’s how they trap the gas! If the plant covers up a stomata, and the malic acid releases the CO2 then boom, you got a botanical baloon.
Now, let’s take it one step further. Fruit structures are different from leaves, obviously, but some of the same design structures just have to apply. And this is waste CO2. What better way to prevent bacterial growth on your seeds than to pump CO2 into the seed pod and push out all the O2?
This is one of the best Dope controversies I’ve encountered in awhile.
I found one source suggesting that pumpkins haven’t ‘‘evolved’’ or changed a whole lot over time, human breeding attempts notwithstanding.
*''Anywhere from three to 20 million years ago, two types of squash did the dirty (pollen-wise, of course) and produce what’s called an allotetraploid baby. Geneticists figured this out by sequencing the modern pumpkin’s genome and comparing it to other squashes in its family. ‘Tetraploid’ means it had four copies of each chromosomes, and ‘allo’ means that each chromosomal pair came from different species. Often when this happens the DNA eventually loses genes and over time becomes diploid again. Not so with pumpkins. Pun’kins lost their duplicate chromosomes randomly, leaving them with just two of each chromosome, one from each parent—which is almost human of them.
Since the pumpkin genome hasn’t changed a whole lot since then, that means today’s jack-o-lanterns are almost identical to ancient ones (assuming that early humans carved gourds)."*
Elsewhere it’s noted that squash/pumpkin ancestors had tough outer shells (no word on “hollow” interiors) and that breeding efforts over time resulted in softer rinds that were easier to break down as well as tasting better.
http://nationalgeographic.com/science/phenomena/2015/11/16/why-pumpkins-and-squashes-arent-extinct/
My take on why pumpkins and squash aren’t as dense as some vegetables/fruits may relate to numerous factors including preservation of seed fertility and ease of spread, partly via the digestive tracts of animals. Hard to imagine many beasts that would want to eat stringy pulp and gulp down seeds whole in preference to solid pumpkin/squash flesh, but I’m not a mammoth or whatever creature still eats these things in the wild.
Why are you hung up on CO2? If plants or fruit or seeds have some hollow space in them I would assume that it’s filled with air. Are there any of these that are air tight before they dry? I assume as they grow they are porous enough to ‘inhale’ air. And I recall that some floating plants that may include water lilies have some kind of filaments that basically hold air bubble in place under them and around their stems.
I wouldn’t say that I am hung up on it. I’m just spitballing, man. You’re also correct in that waterlillies have “hairs” on the bottom that trap bubbles (I used to grow them), but they also have bladders. And you can pop them! For the plant to keep the pressure in those bladders, it’s got to be CO2 right?
OK, consider Kelp. Not exactly a plant per se, but close enough enough for this conversation. It spends it’s entire life underwater, but it uses gas filled bladders. That gas has to come from someplace, and it’s not the ambient environment.
We weren’t talking about water lilies–we were talking about the fruits of pumpkins. They are not directly related to the human invention known as the jack-o’-lantern pumpkin. Water lilies have hollow spaces in their stems that help them float (as do lotuses.) Lots and lots of plants have stems with hollow spaces, especially herbaceous plants that grow quickly and die back in one season–elephant ears and Amorphophallus sp. I know have them from my growing them. It is probably a widespread trait across arums. There are plants and plant-ish things with actual special flotation devices, too, including bladderworts and some brown algae. For all of them, the answer to “how” is going to be some highly technical (and possibly insufficiently studied) description of the interactions of genes and proteins, including especially protein pumps in cell membranes moving specific types of molecules across pressure gradients. For example, from the Wikipedia entry for bladderworts, we have this:
All “hows” are going to be something like that.
Except for the slight problem (which has been pointed out) that the pumpkin is just one of a variety of plants humans derived from the same ancestor. The pumpkin and the zucchini–for example–are two human-built varieties of the same species of plant. In other words, the ancient pumpkin and the ancient zucchini are the same thing–and they don’t look that similar, especially in cross-section.
So has anyone actually tested the gas inside a pumpkin to see whether it is just normal air, or CO2, or some kind of special Halloween swamp gas?
This thread is largely an example of another type of cluster.
Moderator Note
If I take your meaning correctly, this appears to be a threadshit. In any case, let’s refrain from remarks like this that make no constructive contribution to the thread. If you believe posts to be in error, please address this directly rather than making snarky remarks.
Colibri
General Questions Moderator
The thread title’s reference to a “Jank’o’lantern” had me wondering if that was a pumpkin carved to resemble onetime South Dakota governor William Janklow, which is a nightmarish Halloween thought. :eek:
I was actually just trying to be amusing, but yeah, I see it now. Apologies.
Thanks.
??? The bell pepper I just bought from the supermarket looks (approximately) proportionally bigger than the tree peppers I saw growing wild as a kid, and very similar to the hot peppers I grew in our garden. Which had thin skin and smaller voids in proportion to their smaller overall size.
Now I’m going to confuse spandrels with squinches, dang it. And think about it when I shower. :smack:
That’s pretty much what I’m wondering. It’s an interesting question. Well, at least I think so.
And to the board in general: I’m sorry this thing has become a bit of a Charlie Foxtrot, it was not my intention.
Here is a thread from a more focused forum.
Good find. So basically air but with a little more CO₂ and a little less oxygen?