Speaker 1: Welcome to Stuff to Blow Your Mind production of iHeartRadio.
Speaker 2: Hey you welcome to Stuff to Blow Your Mind. My
Speaker 2: name is Robert Lamb.
Speaker 3: And I'm Joe McCormick, and we're back with part two
Speaker 3: in our series about the sowarrow cactus of the Sonoran Desert.
Speaker 3: If you're not very familiar with different cactus species, but
Speaker 3: you've seen a few old Hollywood westerns, or if you've
Speaker 3: just I don't know, looked at picture books made for
Speaker 3: kids or cartoons or something, you will probably recognize the
Speaker 3: ciwaro as the plant icon of the American Southwest. It's
Speaker 3: got this large, round, vertical stem, kind of like a
Speaker 3: tree trunk, and then these limbs that branch out from
Speaker 3: the core when the cactus is mature. We were talking
Speaker 3: in the last episode about how the sowarro is probably
Speaker 3: just what a lot of people think of when they
Speaker 3: think cactus, despite the fact that its geographic range is
Speaker 3: somewhat limited compared to more widely distributed species like the
Speaker 3: prickly pair. But it's just a fundamentally very charismatic plant.
Speaker 3: And the last time we talked about some reasons why
Speaker 3: that might be. It's sort of human shaped, you know,
Speaker 3: it's got a trunk kind of like a human maybe
Speaker 3: with arms looking raised in a posture that's kind of friendly.
Speaker 3: So in the last episode we talked about that. We
Speaker 3: also just generally introduced and described the species. We talked
Speaker 3: about the origin of its scientific name and the tie
Speaker 3: into Andrew Carnegie. We got a bit into its evolution
Speaker 3: and some interesting features like its rib structure and its spines.
Speaker 3: And so we're back today to talk some more about
Speaker 3: the sorrow and should we do a pronunciation note people
Speaker 3: pronounce this word different ways. We have landed on sowarrow,
Speaker 3: but there are other options.
Speaker 2: Apparently, Yeah, sowarrow is what the National Park Service says,
Speaker 2: so we're going with that. But like you look up
Speaker 2: souarrow in webster as, you'll find two different pronunciations for it.
Speaker 2: So if you have one that you prefer, if you
Speaker 2: think we're in the wrong here right in, we'll hash
Speaker 2: it out in listener mail.
Speaker 3: Sure, which probably also mentioned at the top, because we
Speaker 3: rob in the last episode you were reading from this book,
Speaker 3: but actually in the meantime I started reading it as well,
Speaker 3: so we're both using as a major source for these
Speaker 3: episodes a book called The The Well I did it
Speaker 3: there with the har g I started to Saguaro the
Speaker 3: Sowaro Cactus, a Natural History from University of Arizona Press,
Speaker 3: twenty twenty that is by a group of researchers and
Speaker 3: scholars named David Yetman, Alberto Burquz, Kevin Holteen, and Michael Sanderson.
Speaker 2: Yeah. So we'll refer back to that multiple times. But
Speaker 2: it's an easy book to pick up. It's available wherever
Speaker 2: you get your books, and it is a great deal
Speaker 2: more depth. So if you if you really want to
Speaker 2: dive into the world of the Suaro, it's a it's
Speaker 2: a great text to have.
Speaker 3: Now, Robert, I can't believe I didn't ask you this
Speaker 3: in the last episode, or I hope I'm not repeating myself.
Speaker 3: I think I didn't. We're talking about the suarrow because
Speaker 3: you were recently in Arizona. So I assume you were
Speaker 3: in the region of the Sonoran Desert, and so did
Speaker 3: you get close to these things while you were out there?
Speaker 2: Oh? Yeah, it's like you you really can't help but
Speaker 2: do so, Like like I said, for example, you land
Speaker 2: in Phoenix and you leave the Sky Harbor Airport there,
Speaker 2: you're just going to see them everywhere. And if you
Speaker 2: do any amount of hiking within their range, which we
Speaker 2: always try and do. Yeah, you're going to encounter them.
Speaker 2: You're going to encounter big ones, little ones. You're going
Speaker 2: to see the tiny baby suarros. You're going to see
Speaker 2: the giants, You're going to see the ribs, the skeletons. Everything.
Speaker 3: Well, later in this episode, I've got some stuff I
Speaker 3: want to talk about concerning their life cycle and abundance.
Speaker 3: So I hope maybe you can add some uh, some
Speaker 3: commentary from recent firsthand experience, like what ways you see
Speaker 3: these things in their environment?
Speaker 2: Yeah, yeah, it'll be interesting to reflect on that because
Speaker 2: they're you know, they're they're everywhere, so you find yourselves
Speaker 2: as you're walking you you kind of take them for
Speaker 2: granted at times. I mean, you can't see the forest
Speaker 2: for the trees, right and then this this is the forest. Uh.
Speaker 2: But then yeah, they do kind of hypnotize you as
Speaker 2: well at times, and you you can see the human
Speaker 2: form in them. You can see you know, you see
Speaker 2: those ribs, and you start thinking of them as a
Speaker 2: as a living thing, and so they they still cast
Speaker 2: their spell over you even as you sort of get
Speaker 2: used to them being there.
Speaker 3: Do they make sounds do they creak like trees?
Speaker 2: I don't remember any creaking. No, but but but maybe
Speaker 2: I just didn't hear it. We certainly wasn't out there
Speaker 2: in any degree of wind, as I recall. All right, well,
Speaker 2: I want to pick up talking about the relationship between
Speaker 2: the sorrow and rain. So summer moisture from summer rains
Speaker 2: is vital to the sorrow in the form of late
Speaker 2: summer or fall monsoon season rainfalls in the Sonoran Desert.
Speaker 2: And we've already referenced their particular temperature requirements as well,
Speaker 2: like they have a part of their whole range issue
Speaker 2: is they can sustain certain amounts of freezing temperatures, but
Speaker 2: only a certain amount. And it's kind of like, you know,
Speaker 2: a few different factors what they can physically handle themselves,
Speaker 2: and then also the sort of power ups they get
Speaker 2: from their environment.
Speaker 3: Yeah, and being in the desert, you know, they're vulnerable
Speaker 3: to temperature fluctuations on both ends, like getting roasted and
Speaker 3: desiccated by the hot sun in hot weather and also
Speaker 3: suffering freezes, especially in the northern part of their range,
Speaker 3: so they have to protect against they're fighting two fronts there.
Speaker 2: Yeah, so their flowering period evolved to take advantage of
Speaker 2: this particular need for summer moisture, they flower ahead of
Speaker 2: the monsoon rains, giving plenty of time for their fruit
Speaker 2: to develop and seeds to be distributed in time for
Speaker 2: the deluge. Their flowers are pretty big, so eight to
Speaker 2: ten centimeters, are three to four inches in diameter and
Speaker 2: white in color. And here's where it gets really interesting.
Speaker 2: They open at night, generally after ten pm. And remember
Speaker 2: we're mostly talking about Arizona here, just a slim range
Speaker 2: in California. Arizona doesn't observe daylight saving time, so that
Speaker 2: ten pm is going to be pretty consistent as far
Speaker 2: as clock time goes.
Speaker 3: Regarding the flowers, I actually read this on a USDA
Speaker 3: National Plant Data Center sheet. It's just a fact sheet
Speaker 3: about soorows that mention the nocturnal flowers smell like ripe melons.
Speaker 3: Though that did make me imagine, like, wait, who's climbing
Speaker 3: up to get up there and smell the flowers?
Speaker 2: Its parallels, Well, you got to do your research. You
Speaker 2: got to get the step ladder out and smell those flowers.
Speaker 3: Yeah, right, so spines.
Speaker 2: So they open up at night? Why night, you might ask, Well, evolutionarily,
Speaker 2: the Suarro's flower game is aimed at nocturnal pollinators in
Speaker 2: the form of bats, such as the nectar feeding lesser
Speaker 2: long nosed bat. I included a picture of this guy
Speaker 2: for you here has a particular Beavis look. Yeah, I
Speaker 2: think you'll find.
Speaker 3: I like that you included a Beavis for reference. But yeah,
Speaker 3: it even it looks a little It's kind of blonde
Speaker 3: like Beavis, but has the Beavis jaw and nose situation.
Speaker 2: Yeah, you'd think that I watched Beavis and butthead all
Speaker 2: the time since I referenced Beavis in the last episode.
Speaker 2: But I haven't actually watched this show in decades. But
Speaker 2: it's a classic. It's a classic, great show. And yes,
Speaker 2: the bat kind of looks like Beavis. And then you
Speaker 2: also have moth pollinators such as hawk moths, so nocturnal
Speaker 2: pollination is key to the evolution of their flowers. However,
Speaker 2: while the flowers open at night, they're still visited during
Speaker 2: the day by daytime pollinators like various bees, and this
Speaker 2: includes indigenous bees and bees that have been introduced, migratory
Speaker 2: white winged doves and the doves and bees in general.
Speaker 2: These two daytime pollinator sources are actually the most successful
Speaker 2: pollinators among the most northern northern of the Souaros, and
Speaker 2: according to the authors of that University of Arizona book
Speaker 2: that we reference, the reason for this is that most
Speaker 2: of the far northern Saros grow beyond the range of
Speaker 2: pollinating bats, and they're only able to survive it all
Speaker 2: up there, most likely due to the bees. So they've
Speaker 2: kind of pushed beyond the range of the pollinators they
Speaker 2: evolve to depend upon, or at least that's the way
Speaker 2: it's shaken out over time. But the bees are keeping
Speaker 2: them going.
Speaker 3: So they have left their beloved beavis spat behind and
Speaker 3: moved on to the bees.
Speaker 2: Yeah, yeah, yeah. The authors point out that the northern
Speaker 2: Souaros likely exhibit decreased genetic diversity due to this, since
Speaker 2: bees and doves have far more limited ranges compared to
Speaker 2: the bats that might travel sixty miles while foraging during
Speaker 2: their own northward migration. Now, beyond these pollinators the seedlings,
Speaker 2: fruit and seeds of the suaro, which are quite small.
Speaker 2: I don't know if we've described the seeds yet, but
Speaker 2: they're very small. They're important for a whole host of organisms,
Speaker 2: various ant and rodent species depend on the seeds. I
Speaker 2: don't know if we'll get into it in this episode
Speaker 2: or it'll be a subsequent episode, but humans, of course
Speaker 2: make use of the fruit. We'll come back to that.
Speaker 2: Termites will invade the plant to consume some of the
Speaker 2: soft tissues, but apparently never healthy plant tissue. There's a
Speaker 2: nineteen seventy seven study that the authors referred to here
Speaker 2: by Steinberg and Low, and in it it was revealed
Speaker 2: that the average sorrow produces some forty million seeds in
Speaker 2: a lifetime. Few of these seeds. Very few of these
Speaker 2: seeds will survive long enough to germinate, and of those
Speaker 2: that do germinate, as few as one individual plant per
Speaker 2: parent plant will survive the first year, which is pretty
Speaker 2: pretty incredible. This despite a ninety percent germination rate given
Speaker 2: ideal conditions. There's just that much out there looking to
Speaker 2: eat the seeds, the fruit, or the sprout itself before
Speaker 2: it gets past that one year point and one year old,
Speaker 2: soorrows are still tiny. I encourage folks to look up
Speaker 2: pictures of these. They If you've ever been to certain beaches,
Speaker 2: you may have encounted sand spurs, these little little little
Speaker 2: prickly bets with tiny spines on them. That's about what
Speaker 2: a baby, a one year old sorrow looks like.
Speaker 3: Yeah, those things are the bane of dull being walked
Speaker 3: near the beach.
Speaker 2: But yeah, they're so tiny, but yet they will become
Speaker 2: in time and given given that the correct role of luck,
Speaker 2: they will become giants.
Speaker 3: Yeah. Well, I guess that feeds right into something I
Speaker 3: wanted to talk about, which is the is the broader
Speaker 3: picture of how slowly Soorrows grow. And you're exactly right
Speaker 3: that the earliest stages of growth are the most excruciatingly slow.
Speaker 3: So studies carried out in Sorrow National Park indicate that
Speaker 3: a sorrow seedling, after it germinates, on average, takes about
Speaker 3: eight years to grow between one and one point five inches.
Speaker 3: So you might see the seed fall leave, come back
Speaker 3: ten years later and it's still you know, it's a
Speaker 3: little little guy like that. Growth rates do accelerate after
Speaker 3: that that early earliest decade, so it's not eight years
Speaker 3: for every inch or inch and a half of the
Speaker 3: cactus's height, but it still grows very slowly across its lifespan.
Speaker 3: The Jetman at All book says that after twenty five years,
Speaker 3: they are usually still less than a meter in height,
Speaker 3: so incredibly slow growth. Depending on regional variations in climate,
Speaker 3: it usually takes somewhere between fifty and one hundred years
Speaker 3: for a swaro to get its first branch, the first
Speaker 3: arm coming out wave and saying hello. Between fifty and
Speaker 3: one hundred years for that, and a major factor in
Speaker 3: the rate of growth seems to be the level of
Speaker 3: moisture in the environment, so wetter conditions mean faster growth
Speaker 3: and earlier branching, or at least usually mean that. The
Speaker 3: authors of the book also note that variation in temperatures
Speaker 3: during the winter to spring period seem to have a
Speaker 3: pretty powerful effect on growth rates, with temperature volatility in
Speaker 3: the early warm season negatively affecting growth, and I think
Speaker 3: this is a fact they link to the idea of
Speaker 3: increased temperature volatility coming with climate change. Obviously that puts
Speaker 3: sorrows somewhat at risk, but even in the most favorable conditions,
Speaker 3: it's probably going to be fifty years before a cactus
Speaker 3: goes from seedling to getting an arm. The normal natural
Speaker 3: full lifespan of the swarow is somewhere between one hundred
Speaker 3: and fifty and two hundred years, so you know they live,
Speaker 3: They live across multiple human generations and take multiple human
Speaker 3: generations even to become the more recognizable mature shape.
Speaker 2: Yeah, and this is something like a number of these
Speaker 2: details important to keep in mind later when we discuss
Speaker 2: the indigenous indigenous mythic dimensions of the Sowara.
Speaker 3: So Another question is when those soarrows get to the
Speaker 3: mature stage, you know, they're reaching the end of their
Speaker 3: lifespan at one hundred and fifty or two hundred years
Speaker 3: of age. How do they die? It seems older, taller
Speaker 3: sonarrows are vulnerable to being blown over by wind and
Speaker 3: to being struck by lightning, which happens most often during
Speaker 3: summer monsoon conditions. In the colder, more northern regions of
Speaker 3: the Sonoran Desert, old soorrows are more likely to die
Speaker 3: from freezes during winter. And this is interesting because whereas
Speaker 3: something like lightning strikes or wind might have a more
Speaker 3: you know, varied you might pick out individuals in a population,
Speaker 3: especially big top heavy ones, or you know, the individual
Speaker 3: lightning strikes might take out individual soorrows in a In
Speaker 3: the more northern regions, a local freeze can kind of
Speaker 3: wipe out a whole crop, a whole local crop of
Speaker 3: cactus all at once. Another interesting fact they were talking
Speaker 3: about is that if you see a sar with a
Speaker 3: branch that droops downward instead of reaching up, you know
Speaker 3: it's got the arm turned down. This is often a
Speaker 3: result of injury from freezing conditions in the past. So
Speaker 3: maybe there was a freeze that didn't fully kill the cactus,
Speaker 3: but it injured the tissues, and so now it's got
Speaker 3: a drooping arm.
Speaker 2: Oh. Interesting.
Speaker 3: Yeah, But beyond the wind, the lightning, and the cold,
Speaker 3: the soorrow book points out some interesting types of vulnerability
Speaker 3: you might not expect, especially given how massive and hardy
Speaker 3: and well defended these plants seem to be. So you
Speaker 3: would think, you know, like nothing can hurt them. You know,
Speaker 3: they got all the spines, they're huge. But the author
Speaker 3: is right. Quote John Alcock, who monitored the same soarrows
Speaker 3: through the year over many years time, found that a
Speaker 3: mechanical injury as simple as constant rubbing by a palo
Speaker 3: verdi or ironwood branch could render a soarrow susceptible to
Speaker 3: disease and ultimate rot. So they are susceptible to especially
Speaker 3: if they get abrasions on their skin. You know, something
Speaker 3: kind of cuts into them, or hurts them, or just
Speaker 3: kind of rubs them enough, they can get these bacterial
Speaker 3: or fungal infections. They can get these infections that ultimately,
Speaker 3: you know, spread through the tissue of the plant and
Speaker 3: kill it. The authors also provide some interesting and I
Speaker 3: think vivid descriptions of the death of a sorrow. To
Speaker 3: paraphrase Hemingway, the soorrow often tends to die slowly and
Speaker 3: then all at once. So the slowly part is that
Speaker 3: you can get this kind of in between life and
Speaker 3: death zombie mode cactus stage where a doomed soorrow has
Speaker 3: been has been lethally injured, like it has been through
Speaker 3: a lethal freeze, but it may continue after that to
Speaker 3: stand upright and produce flowers, that produce flowers and fruit
Speaker 3: for years, but it's not going to survive. It is
Speaker 3: now doomed inevitably to die within a certain timeframe, usually
Speaker 3: less than a decade. But in the time between it
Speaker 3: keeps on living, keeps on doing reproductive activity. But in
Speaker 3: the final stage of death this comes on with shocking speed. Quote,
Speaker 3: what recently appeared to be a healthy plant may over
Speaker 3: a period of a few weeks, turn yellow, then brown,
Speaker 3: then brown, with black streaks, branches will collapse and fall,
Speaker 3: and finally these sickly outer layers will slough off. And
Speaker 3: I connected this with images of the cacti that we
Speaker 3: talked about last time, with that peeled away skin. Look.
Speaker 2: Yeah, yeah, and we see the ribs inside them that
Speaker 2: those hard woody rods that give them their structure and
Speaker 2: their integrity.
Speaker 3: Yeah. And so that structure, that internal structure can help
Speaker 3: continue to hold the cactus up even after its you know,
Speaker 3: softer tissues and the flesh are you know, have been
Speaker 3: critically damaged by freezes, or are infected with rod or
Speaker 3: something like that. But eventually it all, it all falls apart.
Speaker 3: Another thing that the author has mentioned. I didn't make
Speaker 3: a note of this, but I just remembered it is
Speaker 3: you can get a weird situation where sometimes a big
Speaker 3: mature cactus gets knocked over, maybe it gets blown over
Speaker 3: by wind or something, so it falls over, but it's
Speaker 3: still sort of alive for a bit, so it falls
Speaker 3: but continues to produce fruit and flowers.
Speaker 2: Oh wow, Well, I guess we see that with with
Speaker 2: trees as well. Sometimes the tree has been knocked over
Speaker 2: by one or fallen to one cause or another, but
Speaker 2: it's still going to continue doing the best.
Speaker 4: It can't at life.
Speaker 3: The thing I wanted to come back to is that
Speaker 3: before the sowaro gets to the mature reproductive stage of
Speaker 3: its life, it has to pass through a brutal gauntlet
Speaker 3: of survival. Rob You were talking about this in the
Speaker 3: The Unbelievable ratio of like how many seeds are produced
Speaker 3: versus how many actually survive to become a mature adult cactus. Again,
Speaker 3: most of the info here is coming from that the
Speaker 3: Yetna at All book. You mentioned earlier that the swaro
Speaker 3: tends to set fruit in the early summer, and this
Speaker 3: is usually going to be between June, mid June and
Speaker 3: early July, and that this is timed to come right
Speaker 3: before the summer monsoon rains. This is because the seed,
Speaker 3: you know, the goal is there's a seed inside the fruit,
Speaker 3: and the plant wants to disperse those seeds. And the
Speaker 3: seeds are going to be dispersed either by animal transport,
Speaker 3: so they'll be dispersed in the maybe the feces of
Speaker 3: an animal that ate the fruit. This could be a
Speaker 3: bat or one of many species of bird, or sometimes
Speaker 3: it'll disperse just by falling. You know, it's not going
Speaker 3: to get as far that way. But yeah, it's trying
Speaker 3: to disperse the seeds. But when the seed hits the ground,
Speaker 3: the seed needs warm, moist soil in order to germinate.
Speaker 3: And the authors we're talking here about how a huge
Speaker 3: amount of the seeds fall in places where they're just
Speaker 3: not going to have a chance to germinate and survive.
Speaker 3: Sometimes they get eaten by granivores like doves and bats,
Speaker 3: and then they'll get pooped out on a rock surface
Speaker 3: or inside a cave roost or some of their dark place,
Speaker 3: or they'll get dropped in an open area that's blasted
Speaker 3: dry by the sun, so they just don't have a chance.
Speaker 2: Now, I do want to add, for anyone who's not
Speaker 2: familiar with this landscape, you do following a heavy rain,
Speaker 2: you do have these wet areas. And I again, I
Speaker 2: am a visitor to the Sonoran Desert. I don't regularly
Speaker 2: spend my time there, but on my most recent trip,
Speaker 2: we did go for a nice hike, a couple of
Speaker 2: hikes in the Suarrows range, and it was for me
Speaker 2: kind of surreal to be out. You know, it's it's
Speaker 2: dry in so many respects. You're in the desert. You're
Speaker 2: very concerned about how much water you have on you
Speaker 2: And at the time I was running just a little
Speaker 2: bit low, not dangerously low, but it was a little low.
Speaker 2: It's like, okay, I need to get back and get
Speaker 2: some water. But then you're also passing puddles that are
Speaker 2: still standing. You know, you're you're you're stepping, you're walking
Speaker 2: through soft earth because of the recent rain, and so yeah,
Speaker 2: it can almost seem it can be very difficult to imagine,
Speaker 2: I think if you haven't encountered this in this environment.
Speaker 3: Yeah, yeah, so there will be seasonal rains and that
Speaker 3: we'll get more into this in a minute. But the
Speaker 3: swarrow is very biologically poised to take maximum advantage of
Speaker 3: when these frequent and seasonal rains do come, so that
Speaker 3: it has water stores to tide it over through the
Speaker 3: periods of drought. But the seedling has all these things
Speaker 3: to contend with, it might get dropped in a place
Speaker 3: that's not favorable for germination. Not to mention how rarely
Speaker 3: in time the overall climatic conditions align for the seedlings
Speaker 3: to germinate. The authors of the book note that quote
Speaker 3: the necessary conditions for germination of seeds and survival of
Speaker 3: seedlings seldom occur, perhaps ten times per century, often less
Speaker 3: frequently still, so that's sort of the good case scenario
Speaker 3: tend to. You know, it can go be a long
Speaker 3: time in between the years when things work out just
Speaker 3: right for the young souarros to you know, to germinate
Speaker 3: and then to survive through their youngest lives. And this
Speaker 3: leads to two very interesting consequences. One is areas with
Speaker 3: tons of Sorrows all roughly the same size, and that's
Speaker 3: because they're all pretty much the same age. It's like
Speaker 3: a cohort or a crop that came from one of
Speaker 3: these periods when they all grew up together, when the
Speaker 3: conditions were right, and so you're not getting a lot
Speaker 3: of in between because you know, there are long gaps
Speaker 3: in between these periods when conditions are right. And it
Speaker 3: also leads to areas that are Soorrow habitats, but at
Speaker 3: certain times in history seem to have no mature soarrows,
Speaker 3: and this latter condition can can cause and historically has
Speaker 3: caused periods of what we might call illusory extinction. So
Speaker 3: the authors mention this in the case of the eastern
Speaker 3: unit of Soorrow National Park, where between the time the
Speaker 3: park was established in nineteen thirty six, and some surveys
Speaker 3: that were done in the nineteen sixties, nearly all of
Speaker 3: the mature souarros disappeared. Quote, what was once a soorrow
Speaker 3: forest became a comparatively uninteresting and structurally nondescript desert landscape.
Speaker 3: Now that's alarming.
Speaker 2: Yeah, yeah, I believe this is the case where they
Speaker 2: have some photographs in the book of this Yeah.
Speaker 3: Yeah, And some casual observers were deeply disturbed. You know,
Speaker 3: they thought the suarros had gone extinct in the area,
Speaker 3: but they had not. The reality was that people were
Speaker 3: observing the effects of this reproductive pattern where the right
Speaker 3: conditions for germination and survival of seedlings only happen on
Speaker 3: the timescale of decades. Then you pair that with the
Speaker 3: extremely slow growth of the seedlings, and you can get
Speaker 3: periods where nearly all of the mature saros in the
Speaker 3: region reach the end of their natural lifespan, they die,
Speaker 3: and the younger generation of souarros are still tiny. So
Speaker 3: it looks like the cactus has just disappeared from the landscape,
Speaker 3: but it hasn't. And in fact, in the case I
Speaker 3: just talked about the historical case with the eastern part
Speaker 3: of Suarro National Park, there was an additional human factor involved.
Speaker 3: Researchers figured out why this illusory extinction occurred between the
Speaker 3: thirties and the sixties, and it was the combination of
Speaker 3: the generational dying of a crop of mature souarros plus
Speaker 3: several decades of climate being not very favorable to seedlings,
Speaker 3: plus human behavior in the area, primarily livestock grazing, which
Speaker 3: meant you know you're going to have cattle or whatever
Speaker 3: live stock just tramping through the area, so that you
Speaker 3: know that is negatively affecting the seedlings, but also people
Speaker 3: cutting down woody trees for firewood or to fire kilns.
Speaker 3: And when these human activities were eliminated, the Suaros bounced
Speaker 3: back in the area and the cactus forest grew again.
Speaker 3: Now here's an interesting question. Why would people cutting down
Speaker 3: woody trees for firewood have an effect on soarrow seedling growth.
Speaker 3: This is another really interesting part of the young Souarro's
Speaker 3: survival gauntlet. So warrow seedlings need protection, and for this
Speaker 3: protection they rely often on what are known as nurse
Speaker 3: plants or nurse trees. So rob I wonder if this
Speaker 3: matches with your experience of looking for the little seedlings
Speaker 3: out in the desert. If you go out into the
Speaker 3: desert and find tiny soorrow seedlings thriving, especially in the
Speaker 3: colder parts of the Sawaro Range, the more northern parts,
Speaker 3: it's usually the case that these seedlings are hiding under
Speaker 3: the protective cover of a larger established plant, with the
Speaker 3: most common species including the pallaverdi, the ironwood, creosote, mesquite,
Speaker 3: and another shrub called the triangle leaf bersage or barsage.
Speaker 3: I don't know how you say that, did you observe
Speaker 3: this kind of thing? I've got a picture, by the way,
Speaker 3: you can look at in the outline, rob where you've
Speaker 3: got these young sowarrows, all kind of they're almost gathered
Speaker 3: like children around a mesquite tree. You know, they're under
Speaker 3: its branches and they're springing up around it.
Speaker 2: This is this is this is fascinating. Yeah, I didn't.
Speaker 2: I don't think I directly observed this or at least
Speaker 2: identified it as such. But I think part of that
Speaker 2: is that and this is another thing that might not
Speaker 2: be obvious to folks who haven't visited this environment, is
Speaker 2: that you do have a lot of plant life. It's again,
Speaker 2: we have this kind of like Looney Tunes and old
Speaker 2: Western vision of like a desolate landscape with just a
Speaker 2: few cactus columns holding up the sky. And it's not
Speaker 2: the case. It's a it's a very very botanically diverse area.
Speaker 2: There's so many different types of cacti as well as
Speaker 2: as other plants that have evolved to thrive in dry conditions,
Speaker 2: and so you see this multi layered effect going on,
Speaker 2: things living and thriving in the shadow of other plants,
Speaker 2: you know, pretty much throughout these landscapes.
Speaker 3: Yeah. Yeah, I was thinking, it's funny how when I
Speaker 3: was a kid, I used to picture the desert as
Speaker 3: essentially sand dunes like you might get in the rubolcalli
Speaker 3: or something just like sand dunes with no plant life
Speaker 3: except occasionally a souaro cactus poking up out of them.
Speaker 3: And so no, the reality is something more mixed. You know.
Speaker 3: You will get this actually quite crowded scrub or shrub landscape,
Speaker 3: you know, with a lot of kind of hardy, thorny
Speaker 3: kind of plants, and then the cactus is coming up. Yeah.
Speaker 2: I kind of go back to the to the the
Speaker 2: observation that Frank Loyd Wright made that the desert was
Speaker 2: felt like the bottom of the ocean, you know, and
Speaker 2: like the bottom of the ocean is very diverse, but
Speaker 2: is different compared to say a forest that one might
Speaker 2: be used to, or you know, certainly a more temperate zone.
Speaker 3: So coming back to nurse plants and nurse trees, if
Speaker 3: a soorro seed manages to reach warm, moist soil and
Speaker 3: actually germinate, which again many do not, it first puts
Speaker 3: out these two tiny seed leaves called coudledans, And unlike
Speaker 3: the flesh of the adult cactus, which is protected by
Speaker 3: both sharp spines and a kind of inherent nastiness and unpalatability.
Speaker 3: Remember we talked last time about how you cannot just
Speaker 3: cut and chug or cut and chomp the flesh of
Speaker 3: a soorrow. It will make you sick. It's not good
Speaker 3: for you. The flesh of the soorrow is actually tough, acidic,
Speaker 3: contains irritants. It's just like not very palatable. There are
Speaker 3: some creatures that can kind of consume it. But unlike that,
Speaker 3: the tender cudaledans of a freshly germinated seed are relatively
Speaker 3: easy pickings for rabbits, mice, and pack rats, ants, birds,
Speaker 3: all kinds of things want to eat the seedlings. The
Speaker 3: seedlings are also easily crushed underfoot by larger animals like
Speaker 3: deer or grazing cattle you know, livestock animals, and they
Speaker 3: are vulnerable to the sun, so if they don't have
Speaker 3: adequate shade, they will get roasted and desiccated. On the
Speaker 3: other hand, if they don't have protection against the cold,
Speaker 3: they will easily freeze to death because they don't have
Speaker 3: the mass that the adult cactuses have that helps protect
Speaker 3: them against freezing as they don't have the mass or
Speaker 3: the defense mechanisms of mature souarows that allow them to
Speaker 3: survive these short dips below freezing temperatures. So the authors
Speaker 3: of the book right quote, nurse plants are so named
Speaker 3: because their shade branches litter, plus the other plants that
Speaker 3: grow in their shade shelter the seedlings from sunburn and freezing,
Speaker 3: protect them against trampling, conceal and shelter them from herbivores, and,
Speaker 3: in the case of some luguminous trees, provide a nitrogen
Speaker 3: enriched soil environment. So the nurse plant offers the whole package.
Speaker 3: It keeps you from burning. Not burning keeps you from
Speaker 3: dry you know, getting too hot, drying out and desiccating
Speaker 3: keeps you from freezing, keeps animals from eating you or
Speaker 3: crushing you. And sometimes it even gives you some natural fertilizer.
Speaker 3: So it's a nice deal, right. It would almost be
Speaker 3: nice if the soaros could find a way to pay
Speaker 3: back their nurse plant somehow, But in this case, what
Speaker 3: goes around does not come around, because it seems what
Speaker 3: often happens is by the time the sowarrow is becoming
Speaker 3: large enough that it has its own defenses and it
Speaker 3: has enough mass to survive frosty weather and doesn't need
Speaker 3: the nurse plant's protection quite so much anymore. It also,
Speaker 3: at this point has a pretty robust root structure. Now
Speaker 3: we haven't talked a lot about the root structure of
Speaker 3: the toworro, but it tends to unlike other plants which
Speaker 3: have a deeper taproot goes down deeper in the soil,
Speaker 3: the soworrow tends to have a wide, shallow root structure.
Speaker 3: And what this does is it kind of sucks up
Speaker 3: a lot of the rain water that would previously have
Speaker 3: seeped down into the soil and been absorbed by the
Speaker 3: deeper roots of the nurse tree, and in this way,
Speaker 3: the growing soworrow may quite often sort of murder the
Speaker 3: plant that raised it, or if that's putting it too strong,
Speaker 3: it at least starts to outcompete the plant that raised it.
Speaker 3: Very is this the thanks I get situation? However, because
Speaker 3: the growth of the sorrow is so slow, the author's
Speaker 3: point out that this process never serves to wipe out
Speaker 3: the population of nurse plants in an area because the
Speaker 3: nurse plants have plenty of time to reproduce and recruit
Speaker 3: new generations before they are sort of betrayed and destroyed.
Speaker 2: Yeah, the betrayal and destruction is still a very slow
Speaker 2: process for the sowarro.
Speaker 3: Also, I mentioned that the association between soorrow seedlings and
Speaker 3: nurse plants is stronger in the northern part of the
Speaker 3: soarro's geographic range. The authors of the book right that
Speaker 3: in the southern regions where you find somorrow, because of
Speaker 3: the higher humidity in the wet season, soworrows actually don't
Speaker 3: do so well under plant canopies. I think I don't
Speaker 3: know all the reasons for this. They don't get deeply
Speaker 3: into it. They say that they kind of suffocate under
Speaker 3: plant canopies. I think it could be that there's, you know,
Speaker 3: just other factors come into play, like they're more in
Speaker 3: competition for light and stuff like that. But whatever the reason,
Speaker 3: they don't do as well under plant canopies in the
Speaker 3: southern part of their range, so instead they are found
Speaker 3: more isolated from other plants in rocky areas, where they
Speaker 3: rely on rocks and boulders to provide the kind of
Speaker 3: shelter that something like palloverdi and other plants provide further north.
Speaker 2: Yeah, yeah, this is this is this is fascinating again.
Speaker 2: It It may seem counterintuitive to many to think about
Speaker 2: a cactus as being at all vulnerable to the sun,
Speaker 2: or to think about freezing temperatures in a desert environment,
Speaker 2: but these are all definitely in play.
Speaker 3: One thing I wanted to briefly come back to that
Speaker 3: the authors mentioned, which I thought was kind of interesting,
Speaker 3: is when they say that the cactuses are protected not
Speaker 3: just directly by the nurse plant, but by the community
Speaker 3: of other plants that grow up in the shelter of
Speaker 3: the nurse plant. So it's almost like the nurse plant
Speaker 3: provides a kind of an environ meant of collective defense
Speaker 3: by you know, by by shading and protecting these plants.
Speaker 3: A lot of the plants gathered there, and they also
Speaker 3: kind of help shade and protect each other.
Speaker 2: That's a great point. And I think this is another
Speaker 2: thing that it can seem counterintuitive to us because of
Speaker 2: our agriculture brains. You know, we think about monocrops. We
Speaker 2: think about, oh, there's the crop. There's a million of
Speaker 2: them right next to each other doing well. As opposed
Speaker 2: to the more the natural environment you'll encounter or the
Speaker 2: approach that you'll see in like horticulture, where there's a
Speaker 2: realization that no, it's not just this one plant growing there.
Speaker 2: It's like this plant is growing next to this one,
Speaker 2: in the shade of this one, in the partial shade
Speaker 2: of this one, in the soil that is manipulated by
Speaker 2: this one. You have an entire ecosystem going on there,
Speaker 2: and it's it's more than it's more than just the individual.
Speaker 2: And I guess part of that too is like humans
Speaker 2: have an individual spirit, and we are also often prone
Speaker 2: to think about ourselves as being disconnected from everyone else
Speaker 2: around us in the world and the people that came
Speaker 2: before us.
Speaker 3: But I think another way that it's interesting relating to
Speaker 3: ourselves is that kind of like the relationships between humans.
Speaker 3: You know, it's not purely it's not usually as simple
Speaker 3: as one plant purely helps or harms the other. I
Speaker 3: mean there it's a complex web of interactions and when
Speaker 3: in which the different organisms are both helping and hurting
Speaker 3: each other in complex ways.
Speaker 2: Yeah. It reminds me about our various discussions about parasites
Speaker 2: and symbiosis and how sometimes the line between one and
Speaker 2: the other is a little a little hard to navigate,
Speaker 2: like when where does where does parasitism end and something
Speaker 2: a little more even begin? Does it start as one
Speaker 2: thing and become another? Yeah? It gets a little money.
Speaker 3: All right, are you good if we talk a bit
Speaker 3: about metabolism. Yeah, So we've already discussed several of the
Speaker 3: giant Sorrow's adaptations to survive in the dry conditions of
Speaker 3: the Sonoran desert. So again, you've got things like the
Speaker 3: fact that it uses this wide, shallow root structure to
Speaker 3: quickly absorb massive amounts of water after fleeting rains. It
Speaker 3: has this waxy epidermis and water storing tissues that allow
Speaker 3: the cactus to hold huge amounts of extra moisture within
Speaker 3: its flesh. And some of the authors we talked about
Speaker 3: in the last episode compared the cactus to just an
Speaker 3: enormous drum of water, like a giant standing drum of
Speaker 3: what I mean, that's quite true, Like much of its
Speaker 3: mass is water.
Speaker 2: Yeah, they're bright green, while everything other trees in the
Speaker 2: vicinity have just turned to like brown, you know, dried out,
Speaker 2: almost like a deathly state, and the cactus, the soarro
Speaker 2: is still glowing green.
Speaker 3: Yeah, full of water, but once again, not drinkable water.
Speaker 3: It's you know, it's trapped in some kind of mucilage
Speaker 3: with all sorts of stuff, chemicals, and so.
Speaker 2: You yeah, not to drink even in survival situations, especially
Speaker 2: in survival situations where your dehydration is not going to
Speaker 2: be helped by nausea, vomiting and diarrhea.
Speaker 3: Yeah, and so there's that, but even counterintuitive things like
Speaker 3: we talked the last time about how you might think
Speaker 3: the spines are only to deter herbivores from eating the
Speaker 3: flesh of the cactus, like to keep them away or
Speaker 3: to do other things like prevent them from rubbing against it.
Speaker 3: And you know, the spines do help with that, but
Speaker 3: they also help with water and they help with controlling
Speaker 3: the microclimate around the cactus because the spines help shade
Speaker 3: the surface of the cactus under the hot sun, mitigating evaporation.
Speaker 3: And they also i'll trap a boundary layer of warm,
Speaker 3: humid air around the souarro's skin, kind of like wearing
Speaker 3: a sweater.
Speaker 2: Yeah, that's crazy.
Speaker 3: But one interesting water conscious adaptation we haven't talked about
Speaker 3: yet is that souarros use what's called crasulation acid metabolism
Speaker 3: or CAAM. That's the acronym the CAAM photosynthesis. If this
Speaker 3: sounds familiar to listeners, we did briefly talk about this
Speaker 3: in an October episode from a few years ago where
Speaker 3: we were getting into the subject of a Spanish moss
Speaker 3: monster that was featured in an episode of cul Check
Speaker 3: the Nightstalker. But the connection to Spanish moss is that
Speaker 3: it also makes use of cresulation acid metabolism for roughly
Speaker 3: the same reason as the cactus, which is to preserve moisture.
Speaker 3: So what is CAM photosynthesis? Like other plants, the sowarro
Speaker 3: gets its energy through photosynthesis, So, in simplified terms, it
Speaker 3: uses sunlight to power a series of chemical reactions which
Speaker 3: take carbon dioxide that it absorbs from the air through
Speaker 3: these little holes. Most plants have these little holes on
Speaker 3: the undersides of their leaves. In the case of the cactus,
Speaker 3: it's going to be these little holes in the stem
Speaker 3: which can open and close. These are called stomata, and
Speaker 3: they open and close to absorb carbon dioxide from the air,
Speaker 3: and then they fix that carbon dioxide into sugars into carbohydrates.
Speaker 3: And so for this reaction, the plant actually does need water,
Speaker 3: which it absorbs through its roots, and the chemical reactions
Speaker 3: produce the necessary carbohydrates for the plant to live, sustain itself,
Speaker 3: and grow and reproduce. These are the energy storing molecules.
Speaker 3: And then the reactions also produce oxygen as a byproduct,
Speaker 3: which is very lucky for us, lucky for all of
Speaker 3: the oxygen breathing metazoins out there. But the most common
Speaker 3: form of photosynthesis in the plant kingdom is known as
Speaker 3: C three carbon fixation. Something like ninety percent of plants
Speaker 3: use C three. There's another type known as C four
Speaker 3: carbon fixation. Crasulation. Acid metabolism is an alternate form of
Speaker 3: photosynthesis that it still does basically the same thing. You know,
Speaker 3: the beginning and end is roughly the same, but it
Speaker 3: uses a few extra steps. The CAM pathway comes with
Speaker 3: a reduced total carbon carbon output, so it's gonna be
Speaker 3: less productive overall for the plant. But what this pathway
Speaker 3: sacrifices in total energy molecule production, it makes up for
Speaker 3: in water preservation because it saves water. Most species of cacti,
Speaker 3: which are adapted to hot and dry conditions use CAM photosynthesis.
Speaker 3: So what's the trick here. I'm not going to go
Speaker 3: into a full depth on the chemistry, but the major
Speaker 3: macro scale distinction of camp photosynthesis is that it allows
Speaker 3: the plant to keep its stomata closed during the daytime.
Speaker 3: And remember that the stomata are these little tiny holes
Speaker 3: or pores in the skin of the plant. Again most
Speaker 3: often on the underside of leaves, but in the cactus
Speaker 3: they're going to be on the outer the layer of
Speaker 3: the stammer of the arms, and these little holes allow
Speaker 3: the exchange of gas and vapor with the air outside. Now,
Speaker 3: a C three pathway plant will keep these pores open
Speaker 3: during the daytime so that the plant can continuously absorb
Speaker 3: carbon dioxide from the air while the sun is shining
Speaker 3: to power the photosynthesis in its leaves, so in the
Speaker 3: C three pathway, it's like the raw materials are being
Speaker 3: delivered to the factory while the assembly line is running.
Speaker 3: But for the suaro in the desert environment, having the
Speaker 3: stomata open during the day is a dicey proposition because
Speaker 3: the sun is blazing hot, the air is very dry,
Speaker 3: and those conditions together mean that a lot of water
Speaker 3: inside the plant will be evaporating and escaping while the
Speaker 3: windows are open. So instead, what the soarro does is
Speaker 3: it keeps its pores closed tight during the daytime and
Speaker 3: then opens them instead at night, when there will be
Speaker 3: less evaporation and water losc as temperatures are lower, so
Speaker 3: it feasts on CO two after midnight by the light
Speaker 3: of the moon. Now, like any other plant, it still
Speaker 3: needs sunlight to power photosynthesis. It can't do anything about that.
Speaker 3: It needs to use the sun to power the reactions,
Speaker 3: and there's none of that at night. So cam photosynthetic
Speaker 3: plants have to convert the absorbed carbon dioxide from the
Speaker 3: night time into an organic compound called malic acid, where
Speaker 3: they can store it for later use. Now it's important
Speaker 3: to note that malic acid is not an especially weird
Speaker 3: or exotic compound. In fact, it is produced by I
Speaker 3: think every plant on Earth, or if not every plant,
Speaker 3: nearly every plant. Most plants at least maybe all of
Speaker 3: them make this stuff. And you are already quite familiar
Speaker 3: with malic acid. I can guarantee by taste because it
Speaker 3: is the main chemical responsible for the tart flavor, and
Speaker 3: a ton of fruits like unripe apples, grapes, pears, and plums, apricots,
Speaker 3: all these fruits are going to have a sourness that
Speaker 3: comes from malic acid. Now, of course, it's not the
Speaker 3: only source of sourness in fruits. You also have citric acid,
Speaker 3: which you get in citric fruits and stuff. But malic
Speaker 3: acid is going to be the tartness in a lot
Speaker 3: of natural fruits and some vegetables too. I think it
Speaker 3: may be a dominant flavor in rhubarb, I think I've read.
Speaker 3: And one in Tristing fact I came across is that
Speaker 3: it is sometimes even used as the vinegar flavor in
Speaker 3: salt and vinegar potato chips. Are you a salt and
Speaker 3: vinegar guy, Rob.
Speaker 2: You know I'm not a huge potato chip guy, But okay,
Speaker 2: if I potato chips are on like say, the gaming table,
Speaker 2: and they often are I'm gonna be more drawn to
Speaker 2: salt and vinegar than I am to whatever kind of
Speaker 2: like spicy face melting flavor has been has been tried
Speaker 2: it out?
Speaker 3: Oh yeah, the extreme flavors haberneuro death or whatever.
Speaker 2: Yeah, I love those things, and I support it because
Speaker 2: that means I am less likely to eat a whole
Speaker 2: bunch of those chips.
Speaker 3: Right. So, the one thing that I thought was kind
Speaker 3: of surprising is that you would use malic acid as
Speaker 3: a vinegar flavor in a salt and vinegar chip, because
Speaker 3: it's supposed to be vinegar flavor, so you'd think that
Speaker 3: would come from vinegar, which is based on acetic acid.
Speaker 2: I never thought. I just assumed there would be in
Speaker 2: the factory, like some sort of like vinegar mister hitting
Speaker 2: the potatoes slices at some point.
Speaker 3: So I think some chips do use the powdered form
Speaker 3: of acetic acid on salt and vinegar chips, but other
Speaker 3: chips use malic acid. I was reading about this in
Speaker 3: an article for the website Serious Eats by Dan Suza
Speaker 3: called the Science behind Salt and Vinegar Chips. This guy
Speaker 3: went through and studied the ingredients of a bunch of
Speaker 3: different brands of salt and vinegar potato chips, and he writes, quote, surprisingly,
Speaker 3: a couple of brands in our lineup opt for citric
Speaker 3: acid from citrus fruits, malic acid from apples, lactic acid
Speaker 3: from milk, or even fumeric acid which apparently comes from
Speaker 3: lichen and the quote continues to give them pucker and punch.
Speaker 3: So I was looking through which ones are the ones
Speaker 3: that opt for malic acid. Some very familiar brands like lays,
Speaker 3: Uts and Whys all use malic acid in their flavoring mix.
Speaker 3: So it's not the only flavor there, but it's part
Speaker 3: of the flavoring they use for the chip. And while well,
Speaker 3: not all tartness is exactly the same, you know you'll
Speaker 3: get different acidic types of flavors, and malic acid is
Speaker 3: going to have a slightly different kind of tartness and
Speaker 3: acidity than acetic acid from vinegar or citric acid. So yeah,
Speaker 3: I don't know. I guess they just try different things
Speaker 3: and figure out what flavors they like. But sometimes you're
Speaker 3: going to be getting malic acid in your chips.
Speaker 2: Fascinating.
Speaker 3: So again, malic acid is all over the plant Kingdom.
Speaker 3: It's not unique to cacti, but what makes it special
Speaker 3: in the cresulation acid metabolism plants is that they use
Speaker 3: it to store carbon resources during the off cycle. So
Speaker 3: the carbon from the air is stored in the plant
Speaker 3: as malic acid. It's brought in during the night and
Speaker 3: then turned into malic acid stored there, and then once
Speaker 3: the sun fires up in the daytime, the plant can
Speaker 3: close its pores tight to protect its horde of water
Speaker 3: and minimize evaporation, and then vert the malic acid back
Speaker 3: into CO two inside its tissues and then fire up
Speaker 3: the photosynthetic assembly line. So rough analogy, it's kind of
Speaker 3: like having a form of cold storage. It's a place
Speaker 3: you can store the materials you need when it's not
Speaker 3: convenient to be getting them at the same time you're
Speaker 3: using them.
Speaker 2: And it allows the day shift to continue the night
Speaker 2: shift's work.
Speaker 3: Right. So, I was looking up some other examples of
Speaker 3: camp photosynthesis and familiar plants, especially food crops, and it
Speaker 3: turns out it just keeps popping up in interesting places.
Speaker 3: Pineapples famously actually rely on cam Another plant that uses
Speaker 3: camphotosynthesis to survive in dry conditions is the agave plant,
Speaker 3: the juice of which is fermented and then distilled to
Speaker 3: produce tequila. So anytime you have a marger rita, some
Speaker 3: of the complex sweet and tart flavors that come from
Speaker 3: the tequila element. Of course margarita, you're gonna have what's
Speaker 3: the other stuff in there? I think orange, liqueur or
Speaker 3: something and citrus. Yeah, but the tequila part itself, Some
Speaker 3: of these flavors are downstream products of crasulation acid metabolism.
Speaker 3: Another cam plant is vanilla. Now this one is not
Speaker 3: fully cam. I'll discuss the distinction in a minute, but
Speaker 3: this is interesting because the orchid flower that produces vanilla
Speaker 3: vanilla beans doesn't grow in especially dry conditions like the desert.
Speaker 3: It tends to grow in kind of, you know, moist
Speaker 3: forest conditions like the dense, shady understory of a humid
Speaker 3: tropical forest. So if the I was wondering, if its
Speaker 3: environment is pretty wet, why does it need cam the
Speaker 3: answer to this question. I had a harder time finding
Speaker 3: a very clear CLI answer to this, and I was
Speaker 3: seeing suggestions of different reasons in different sources. So maybe
Speaker 3: it's kind of complicated, but it seems one possible part
Speaker 3: of the answer brings us back to Kulchak, the nightstalker
Speaker 3: and paramou Fa. So remember that Spanish moss is an epiphyte,
Speaker 3: meaning it grows not on the ground but on the
Speaker 3: trunks and branches of trees. And because it grows on trees,
Speaker 3: it can't put roots into the ground to collect moisture,
Speaker 3: so it has to collect moisture from the air and
Speaker 3: directly from rainfall with these epiphytic roots or with these
Speaker 3: things I think called tricombes on its outer tissues. So
Speaker 3: this is a less stable, less dependable way to get
Speaker 3: water compared to having roots sunk in the ground. Thus
Speaker 3: it needs to use cam to protect what water it's
Speaker 3: able to suck out of the fog and out of
Speaker 3: the storm. Vanilla orchids are not full epiphytes, but it
Speaker 3: seems they are semi epiphytes, so they do they have
Speaker 3: roots in the ground, but they climb up trees. They
Speaker 3: climb up the trunks and branches of trees like vines,
Speaker 3: and as they climb up they produce these secondary aerial
Speaker 3: roots to absorb water directly from the air and from
Speaker 3: the rain. So kind of like Spanish moss, the aerial
Speaker 3: roots are a less stable, less consistent way to harvest
Speaker 3: water than the roots sunk in the earth, and so
Speaker 3: this could be a reason why these vanilla flowers rely
Speaker 3: on CAM at least in part. Could be other reasons too.
Speaker 3: It might have to do with light and heat stress
Speaker 3: in their hot environments, maybe as they like climb up
Speaker 3: trees and become exposed to the sun. But whatever the reason,
Speaker 3: when you taste vanilla, you can think about how wow,
Speaker 3: you know? So the compounds that I'm tasting now are
Speaker 3: downstream of growth through in part crysulation, acid metabolism. And
Speaker 3: it's worth noting that the different photosynthesis pathways are not
Speaker 3: mutually exclusive for a plant, so many plants can switch
Speaker 3: between like direct C three photosynthesis and CAM depending on conditions.
Speaker 3: It seems like vanilla orchids do this. A lot of
Speaker 3: camplants use C three when water is abundant, and then
Speaker 3: they switch defensively to the CAM pathway when they are
Speaker 3: under thread of drought. This is called facultative CAM photosynthesis.
Speaker 3: But the swaro is an interesting exception. It is one
Speaker 3: of the rare plants that, as far as we can tell,
Speaker 3: basically never goes into C three mode. It is pretty
Speaker 3: much only CAM, which is called obligate camphotosynthesis and coming
Speaker 3: back to the Jetman at All book, there's this whole
Speaker 3: interesting section about this in a chapter by one of
Speaker 3: the authors, Kevin Halteen. Halteen writes about some experiments that
Speaker 3: demonstrate and study the suarro's obligate relationship to CAM. One
Speaker 3: way you can do this is you put the soworro
Speaker 3: inside an air type plexiglass box and then measure the
Speaker 3: amount of CO two in the air in the box
Speaker 3: over time. And sure enough, these experiments show that carbon
Speaker 3: uptake by the sowarro is almost entirely confined to the
Speaker 3: nighttime it's after midnight. In a period between midnight and
Speaker 3: dawn and the rest of the day, carbon uptake is
Speaker 3: either zero or it's actually negative. So during the day
Speaker 3: it's you know, releasing carbon dioxide, which we don't usually
Speaker 3: think of plants doing. So why would that be going on?
Speaker 3: I guess there could be multiple reasons, but Holteine explains
Speaker 3: that this is actually pretty common for cam plants during
Speaker 3: the day because it happens when the malic acid is
Speaker 3: inside the tissues is converted back into carbon dioxide, so
Speaker 3: the photosynthesis can happen some of this co two escapes
Speaker 3: from you know, it leaks out of the plant before
Speaker 3: it can be converted into sugars. And another interesting thing
Speaker 3: that they note is that the suaro shows differential carbon
Speaker 3: uptake across the seasons of the year, regardless of some
Speaker 3: objective external conditions like the amount of water present. This
Speaker 3: seems to be an adaptation related to the fact that
Speaker 3: they grow more in the summer and then they shift
Speaker 3: into a more conservative, safer gas exchange strategy in the
Speaker 3: off season when less new tissue growth is needed.
Speaker 2: Fascinating, fascinating. Yeah, there's such amazing engines really, you know, again,
Speaker 2: it's so easy, especially with such a long living, slow
Speaker 2: growing organism as this, to just think of them as
Speaker 2: almost inert. You know, they're almost indeed like stone columns
Speaker 2: holding up the sky. But they are very active in
Speaker 2: what they're doing is amazing.
Speaker 3: Yeah, and so much of it is just centered around
Speaker 3: gathering and protecting water resources. I mean, it's to psychologize
Speaker 3: something that's actually just biological adaptation. It's like a water obsession,
Speaker 3: you know, it feels like almost a religious orientation toward water,
Speaker 3: which is a metaphor actually that you know that that's
Speaker 3: not new to me suggesting here. You know, people think
Speaker 3: of that often with desert organisms having a kind of
Speaker 3: obsessive or religious devotion to the water and their environment.
Speaker 3: It's what everything revolves around.
Speaker 2: Absolutely. Yeah, Now we're gonna go ahead and close out
Speaker 2: this episode here, but we have a lot more to
Speaker 2: talk about with the Sorrow, so well at least do
Speaker 2: one more episode, and in the next episode of Belief,
Speaker 2: we're going to get into indigenous traditions that involve the soarrow.
Speaker 2: We're going to talk about some other animal interactions and
Speaker 2: some other growth features of the soaro itself, So be
Speaker 2: sure to tune in for that episode, and in the meantime,
Speaker 2: certainly feel free to go ahead and ride in. Any
Speaker 2: of you desert dwellers or desert tourists out there, or
Speaker 2: cartoon watchers and Western officionados. We'd love to hear from
Speaker 2: you as well, if you have thoughts on anything we've
Speaker 2: discussed about the souaros thus far, or any media representations
Speaker 2: and so forth. It's all fair game. Just a reminder
Speaker 2: to everyone out there that Stuff to Blow your Mind
Speaker 2: is primarily a science and culture podcast, with core episodes
Speaker 2: on Tuesdays and Thursdays. Short form episode on Wednesdays and
Speaker 2: on Fridays, we set aside most serious concerns to just
Speaker 2: talk about a weird film on Weird House Cinema. Yes,
Speaker 2: I'm not sure if we have watched a film with
Speaker 2: the sowaro in it. We have watched some, We've watched
Speaker 2: desert movies. We've watched Arizona movies, but I don't know
Speaker 2: if we've watched anything filmed specifically in the Sonoran Desert.
Speaker 2: I'd have to go back and check, but I'm not sure.
Speaker 3: I was going to say, I think there's some sowarro
Speaker 3: in the movie Tarantula, the Okads Giant Spider movie that.
Speaker 2: Would make sense. Yeah, yeah, number of Arizona movies. I
Speaker 2: need to go back and check. By Yes, bright In,
Speaker 2: We'd love to.
Speaker 3: Hear from you huge thanks as always to our excellent
Speaker 3: audio producer JJ Posway. If you would like to get
Speaker 3: in touch with us with feedback on this episode or
Speaker 3: any other, to suggest a topic for the future, or
Speaker 3: just to say hello, you can email us at contact
Speaker 3: a Stuff to Blow your Mind dot com.
Speaker 1: Stuff to Blow Your Mind is production of iHeartRadio. For
Speaker 1: more podcasts from My Heart Radio, visit the iHeartRadio app,
Speaker 1: Apple podcasts, or wherever you listen to your favorite shows.