"It should be dead, but it's not. Just like a ghost."

October 7, 2016 10:16 AM

The mystery of California's ghost redwoods may have been solved.

Brilliant October sunshine filters through the high forest canopy, where the silver-green needles of healthy trees soak up rays and turn them into fuel. But the albino tree lacks chlorophyll, the green pigment that allows plants to make food from light via photosynthesis. It is incapable of the one thing that all trees must do to live.… The mystery of the albino redwood has stumped researchers for more than a century. The trees are so improbable that those who haven't seen them up close sometimes question whether they can exist at all. But Moore is convinced that this ghost story has a scientific solution - one that should change how we view not just the albino trees, but also the entire forest.

Albinos are exceedingly rare - there are only 406 in existence, by Moore's latest count. And redwoods as a species are notoriously complex. The trees' genomes have 32 billion base pairs to humans' 3.2 billion, and they carry six copies of each chromosome instead of two. No one has successfully sequenced the redwood genome, making it impossible to pinpoint the mutation that causes their albinism.

Redwoods can also clone themselves, further complicating scientists' understanding of them. Vast rings of related plants communicate via their roots, and during the hard months of winter and early spring, they'll distribute nutrients evenly among themselves. Scientists have spilled dye onto trees at one end of a grove and traced it through the root network all the way to the other side.

"Most people, when they come to the redwood, they look up at the canopy," Kuty says. "But down is where the action is."

posted by Lexica (23 comments total)

oh my god is there a giant bunnicula pls say yes
posted by poffin boffin at 10:30 AM on October 7, 2016 [35 favorites]

Since the albino redwoods are sucking sugars out of the shared root system from photosynthesising neighbors, there's definitely some vampirism (or possibly benign symbiosis) going on.
posted by figurant at 10:33 AM on October 7, 2016 [8 favorites]

....Team Redwood?

*ducks*
posted by I-baLL at 10:35 AM on October 7, 2016

there's definitely some vampirism (or possibly benign symbiosis) going on.

Y E S
posted by poffin boffin at 10:47 AM on October 7, 2016 [4 favorites]

Since I scanned for it, here's the part with the theory:

He found that the albino needles were saturated with what should have been a deadly cocktail of cadmium, copper and nickel. On average, white needles contained twice as many parts per million of these noxious heavy metals as their green counterparts; some had enough metals to kill them ten times over. Moore thinks faulty stomata - the pores through which plants exhale water - are responsible: plants that lose liquid faster must also drink more, meaning that the albino trees have twice as much metal-laden water running through their systems.

"It seems like the albino trees are just sucking these heavy metals up out of the soil," Moore said. "They're basically poisoning themselves."

Moore's theory - which he presented at a redwood conference last month and hopes to publish next year - is that albino redwoods are in a symbiotic relationship with their healthy brethren. They may act as a reservoir for poison in exchange for the sugar they need to survive.

"It's really interesting work, and I'm so glad he's doing it," said Jarmila Pittermann, a plant ecophysiologist at the University of California in Santa Cruz who studies redwood water transport systems. She agreed that poor stomata control is probably responsible for the build up of heavy metals in the albino plants.

"As far as conferring advantage to the healthy trees," she added, "I think that more work needs to be done."
posted by The Minotaur at 10:53 AM on October 7, 2016 [18 favorites]

Forests. I love 'em.
posted by Atreides at 10:57 AM on October 7, 2016 [2 favorites]

there's definitely some vampirism (or possibly benign symbiosis) going on.

Peter Wohlleben, author of The Hidden Life of Trees would suggest neither vampirism nor benign symbiosis, but instead a deliberate making of nutrients available to the albino trees. According to his work, trees are intimately connected and 'altruistic'.
posted by Thella at 11:01 AM on October 7, 2016 [7 favorites]

"As far as conferring advantage to the healthy trees," she added, "I think that more work needs to be done."

A little redwood shade being thrown there?
posted by Flashman at 11:01 AM on October 7, 2016 [2 favorites]

The symbiosis theory might be right, but I like the idea that these are purely parasitic mutants that have figured out how to subvert the mechanism that cuts off unproductive members of the root system.

It's like a small village where everybody's good friends with Count Orlok, who might look a little weird but he's good people and definitely has nothing to do with everyone being anaemic and waking up with bitemarks on their necks all the time.
posted by figurant at 11:04 AM on October 7, 2016 [6 favorites]

i'm gonna be this tree for halloween and steal candy from everyone around me.
posted by poffin boffin at 11:35 AM on October 7, 2016 [13 favorites]

I love the discoveries we are making about how complex and interlinked plants are. Though it makes stories like Big Lonely Doug even sadder.
posted by tavella at 11:39 AM on October 7, 2016 [2 favorites]

Maybe albino redwoods should post a question over on ask seeing as they take all the crap in exchange for table scraps.
posted by srboisvert at 11:41 AM on October 7, 2016 [1 favorite]

ghost redwood...idea for Halloween outfit

me like
posted by strelitzia at 12:16 PM on October 7, 2016 [1 favorite]

poor stomata control

It's a normal developmental phase, they'll grow out of it eventually.
posted by Greg_Ace at 12:37 PM on October 7, 2016 [4 favorites]

there's definitely some vampirism (or possibly benign symbiosis) going on.

One thing about living in Santa Carla Cruz I never could stomach; all the damn vampires.
posted by 445supermag at 12:55 PM on October 7, 2016 [5 favorites]

Albino redwoods: nature's sin-eaters
posted by BitterOldPunk at 2:06 PM on October 7, 2016 [7 favorites]

> i'm gonna be this tree for halloween and steal candy from everyone around me.

I like this idea myself (especially as pale as I already am) but my toes aren't dexterous enough to filch candy.
posted by Fiberoptic Zebroid and The Hypnagogic Jerks at 3:19 PM on October 7, 2016 [4 favorites]

A frequent sight in Douglas fir forests is a "mugwump" -- a healed-over stump nourished by neighbouring trees.
posted by klanawa at 4:15 PM on October 7, 2016 [2 favorites]

We had a thread about the ghost redwoods a couple of years ago, before Moore had come up with a theory to account for them, but I thought I saw what was going on with them then, and this is what I said:

After all, redwood relatives are diploid, but redwoods themselves are hexapoloid, implying that the ancestral redwood may have arisen when a diploid seed had each of its chromosomes duplicated three times (or more complicated multi-step variations on that theme) and then grew into the first redwood tree.
...
suppose the albino allele is present at a rate of 1%-- which seems quite high to me.

Then the probability any randomly chosen chromosome has it is 1/100, and if redwoods were diploid (two sets of chromosomes) you'd see it at most in (1/100)(1/100), or one in ten thousand of the population.

But redwoods are hexaploid (six sets of chromosomes), so if it's randomly distributed, you'd see it in (1/100)(1/100)(1/100)(1/100)(1/100)(1/100), or one in a trillion of the population.

I doubt there are as many as a billion redwoods, counting even small seedlings.
...
I think my argument can be turned on its head to show us just why redwoods need to be hexaploid-- which is a major drain on resources available to the tree, and would therefore be a major selective disadvantage-- when all its relatives are able to get along being diploid.

Redwoods in a mature stand are both huge and pretty close together, and that limits the amount of usable light which reaches the forest floor (which has the effect of shading out possible competitors). So much so, I'm guessing, that redwood seedlings themselves would have very little chance of getting high enough to become self-sufficient from their own photosynthesis without a big boost from a mature tree, without, in fact, a long period as essentially a parasite on a mature tree (which is probably a close relative most of the time, kin selection and all that).

So for the mature tree, ghost seedlings could be indistinguishable from healthy ones for many years, and if the prevalence of the ghost allele is high, that could make a strategy of helping seedlings out more expensive than it could possibly be worth if the trees were only diploid or tetraploid, because that many more ghosts would take too much away from mature trees for the forest to sustain itself in its current form, and it would have to become less dense, or the redwoods would have to be much smaller, or both. and that would open the way for possible competitors to grow and compete with the redwoods, conceivably displacing them from some of their range.

So, redwoods are hexaploid to cope with the problems that would otherwise be caused by the high frequency of the ghost allele, I'd say.

I still think this is basically right, and that Moore has made a misstep.

To reiterate and shorten my argument somewhat, there is such heavy shade in a mature redwood forest that seedlings could very, very rarely survive to become mature trees without going through a prolonged parasitic stage in which their growth comes not from nutrients they've photosynthesized themselves, but instead comes from nutrients which are donated to them by surrounding, more mature trees which are close relatives.

But some of those seedlings will turn out to be a waste of resources by the mature trees because they will never be able to photosynthesize because they have deleterious mutations, yet because the relatives are so generous with donated nutrients over such a long period of time, the ghosts can reach considerable size.

To minimize that waste of resources, redwoods don't rely on only two copies of their chromosomes to mask the deleterious recessives that prevent photosynthesis, the way their relatives do -- they have evolved to have six copies of each chromosome!

The Minotaur very generously excerpted Moore's current theory for us:

He found that the albino needles were saturated with what should have been a deadly cocktail of cadmium, copper and nickel. On average, white needles contained twice as many parts per million of these noxious heavy metals as their green counterparts; some had enough metals to kill them ten times over. Moore thinks faulty stomata - the pores through which plants exhale water - are responsible: plants that lose liquid faster must also drink more, meaning that the albino trees have twice as much metal-laden water running through their systems.

"It seems like the albino trees are just sucking these heavy metals up out of the soil," Moore said. "They're basically poisoning themselves."

Moore's theory - which he presented at a redwood conference last month and hopes to publish next year - is that albino redwoods are in a symbiotic relationship with their healthy brethren. They may act as a reservoir for poison in exchange for the sugar they need to survive. ...

But I think there is a very strong case to be made that the ghosts have such a big burden of toxic metals precisely because they don't photosynthesize.

Chlorophyll itself is a chelating compound; in its normal state it contains a chelated magnesium ion which is necessary for it to be able to participate in photosynthesis, and everything I've read seems to suggest that it has a fairly narrow specificity for magnesium.

However, that's not the case for some of its most important catabolites, or breakdown products. Those turn out to have a strong affinity for just the toxic metals that Moore has found to be poisoning the ghosts:

“Non-fluorescent” chlorophyll catabolites (NCCs) are ubiquitous, colourless bilane-type natural products, first identified about 20 years ago. In various senescent leaves NCCs are oxidized, in part, to yellow chlorophyll catabolites (YCCs), which undergo further oxidation to unique pink chlorophyll catabolites (PiCCs). The present work presents the crystal structure of a PiCC, the first of a natural chlorophyll catabolite from a higher plant. The PiCC binds (divalent) zinc-, cadmium-, copper- and nickel-ions with high affinity. Binding of these metal ions to the PiCC is rapid at room temperature. The resulting deep blue complexes represent the first transition metal complexes of a bilin-type chlorophyll catabolite. The structure of the metal complexes has been deduced from spectroscopic analyses, which has revealed an effective tridentate nature of the tetrapyrrolic PiCC ligand. The zinc and cadmium complexes show bright red luminescence, the nickel and copper complexes are non-luminescent. Binding of Zn- and Cd-ions to the PiCC ‘lights-up’ the intensive red fluorescence of the metal-complexes, which is detectable at nM levels of these closed shell metal ions. Formation of transition metal complexes with PiCCs, and related chlorophyll catabolites, may thus also occur in the tissues of plants, notably of ‘heavy metal (hyper)-accumulating’ plants. [my emphasis]

Which means that photosynthesizing redwoods can get rid of toxic metals simply by shedding old needles which contain broken down chlorophyll which has sucked up the toxic metals -- a gambit which is not available to the ghosts.
posted by jamjam at 5:17 PM on October 7, 2016 [20 favorites]

I wanna hear what Lab Girl has to say.
posted by Obscure Reference at 6:20 PM on October 7, 2016

redwood seedlings themselves would have very little chance of getting high enough to become self-sufficient from their own photosynthesis without [...] a long period as essentially a parasite on a mature tree

Just like human seedlings!
posted by heatherlogan at 11:48 PM on October 7, 2016 [1 favorite]

Hey primalux, I was just in the SF Botanical Garden today and overheard someone asking a Garden volunteer about the albino redwood, saying she didn't see it today. The volunteer said it's not there any more - is this true? What happened to it?
posted by Quietgal at 5:21 PM on October 8, 2016

Thanks, primalux - good to know it hasn't died! I'll have to look for it next time I'm in the park.
posted by Quietgal at 7:23 PM on October 8, 2016