https://hortscans.ces.ncsu.edu/uploads/t/h/thermal__51bf44b0...
It's not clear why this matters from the paper, in that it sounds like (but not spelled out) that they are perhaps trying to refrigerate fruit for transport, where the transport itself is not actively refrigerated, merely insulated, so the reduction to target temperature has to occur before shipping. However this was published in 1970, and I'd assume in that part of the world refrigerated shipping and (large) storage was not uncommon?
Aside #1 - undamaged grapefruit will happily store at room temperature for 6 weeks or more, and be the tastier for it.
Aside #2 - received wisdom is that grapefruit, and perhaps most citrus, benefit from one or more frosts to 'sweeten up', though I have never understood the mechanisms for this claim, or how high-water fruit does not burst its vesicles and then deteriorate rapidly.
TFA and this paper you cited may speak to the latter (the fruit content does not freeze overnight as the thermal inertia is so high), and might partially debunk the former.
Harvest time is extremely hectic. There's a very small window to get months worth of produce picked, sorted, cooled, packed and shipped. Cooling is a major bottleneck, because capital for refrigeration is not unlimited. Likewise any delay can be a major issue- if a truck is slow to load, how do you know whether or not you need to re-cool your produce first?
It's well known what temperatures produce does well at (can't be too hot or too cold without MAJORLY affecting end margins) because it's easy to test by setting a fridge to a given temperature. It's much harder to know, for a given type of produce, how fast it will cool or heat, and how long you need to spend doing that. It's not as simple as sticking a thermometer in it, which will create paths for heat to move into and out of the produce. Even then you still don't know what the heat distribution inside the produce is so you can optimize the temperature over as much of the plant as possible.
It's really quite tricky and stuff like this helps farmers a lot. IMO farmers do more actual number math more than almost any other occupation (ex: [1]). Much of it is rules of thumb and guesstimation, but they still are constantly balancing dozens of figures to make choices every day. They're always doing mental calculations in economics, biology and physics. Even if the job wasn't so physically and technically taxing, I would respect the hell out of them just because of the mental workload.
I'll try to stop using that from now on, thanks!
> fantastically fastidious on fruit quality
Great alliterations. Great writing all around. This just made my night.
Mostly, though, it's a matter of the effect on the thread. The value of a comment is the expected value of the subthread it spawns [1]. In this particular community a "Churchill+genocide" comment is pretty well guaranteed to spawn a flamewar, which was not true of the subthread one level up. So it's relative to the community you're participating in.
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que...
I'd rather invite them to read the original Roland Barthe's essay (1967), which has that same title. Additionally, one can read New Criticism's authors on what they called the "intentional fallacy".
I personally wouldn't spend my time skimming through clickbait-y YouTube videos in hopes that I find one that is actually informative instead of a half-assed presentation made to maximize monetization.
(good heavens, the implications - ultra right wing skinheads suddenly willing to reading Pride and Prejudice...)
Are you seriously trying to compare the achievements of Hitler and Churchill in a morally neutral context?
https://en.wikipedia.org/wiki/Pomelo#/media/File:Citrus_gran...
Flavor-wise it undoubtedly is.
Grapefruit didn't evolve naturally. In fact, it's only a couple of hundred years old. It's the way it is because of human intervention.
Grapefruit are a cross, probably, of pomelo and a sweet orange - as you say, not all that long ago. While some grapefruit varieties are quite pithy, pomelos (that I've seen) are very pithy - hence the 'this can only have been even more expensive a protective layer in earlier versions of this plant'.
The question still stands - why is this adaptation useful, given it's probably expensive. (That assumption of mine may be entirely wrong.)
Early species would have been shorter, and all species in the history of this would have fruited long before the individual trees reached 10 metres (I'm guessing even in ideal conditions that implies 10+ years growth). Most would-be consumers of the fruit would be able to reach fruit within the first metre or so (if unable to climb or fly) and anywhere in the tree otherwise.
What kind of animals live, or lived, in wild citrus' native range? Now I'm curious. [EDIT: Himalayan foothills... Macaques? Elephants?]
Or it's selected for particular animals as spreaders? In wild grapes, for example, most are adapted for bird spread (small dark acidic berry, high up in a tree on dangling shoots) but there are a handful of species (vitis labrusca "fox grape" for example, and vitis rotundifolia aka muscadines) that have adapted for mammals and they are quite different: larger berry, lighter colours, strong smell (think Concord), lower acids, slip skin, and a tendency to "shell" (fall off the vine when ripe). They also tend to grow wild in shadier moister areas, e.g. the underbrush where foxes and skunks and racoons etc. will grab them, not birds.
I understand the 'travel far and wide', though of course evolution's not directed, and is there significant difference in fitness & success over the long term for a variation that allows a plant to produce offspring 1km away in one generation (say 5y), rather than taking 2 generations?
(And, of course, it's worse than that. The 10m drop potential isn't realised until the plant is probably 15 years old or more -- at which point the distance / propagation calculation is almost irrelevant, as that specimen would have produced fruit for at least 5 years whose seeds would have travelled the same distances, regardless of this (future) robustness capability.)
Sadly, though, I suspect plant archaeologists have more pressing concerns than this question.
Maybe.
I have a Marsh grapefruit tree, fruiting now (southern hemisphere) as it happens, and I note that it produces particularly pithy progeny. (Ignoring for the moment that Pomelo is one of the parents of the modern grapefruit.)
I don't have a convenient 10 metre drop to test this, and while I have no reason to doubt the veracity of this citation, I'm now consumed with curiosity why this plant has evolved to have this feature.
I expect it's quite an expensive adaptation, and given that modern specimens are the result of a lot of cross-breeding over the years to have juicier pulp and a lower ratio of skin/pith to pulp (ie. reduced resistance to damage) it presumably was even more expensive in ancestor plants.
Standard fruit purpose is to have animals unwittingly propagate the plant -- entice something to eat the fruit, and some time / distance later, deposit the seeds in a fertiliser ball. How does protecting the pulp from these kind of damage assist with that -- unless ancestor trees were spectacularly tall, and ancestor consumers fantastically fastidious on fruit quality.
[1] https://doi.org/10.1088%2F1748-3190%2F11%2F4%2F045002