Rick Shory

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Gibbs economics

I was asked to review the book “Solar Hydrogen Generation: Transition Metal Oxides in Water Photoelectrolysis” in regards to alternative energy production. I loved the geeky chapters because I’m a sucker for any sort of super technical chemistry gossip. But I want to offer my perspective on the gap between such information vs. practical systems. Most people realize there are “complications”, but I would like to share my ideas on how to think of these complications in a systematic way.

I will use an economics analogy to explain a thermodynamic term called “Gibbs energy” (in older publications “Gibbs free energy”). Gibbs energy is the deal-breaker (or -maker) in a physical system, to tell whether it will “go”. It’s like a bookkeeping analysis to see if a business model is viable.

This is of course way oversimplified, but: You have raw profit, and you have organization costs. If you have enough profit, you can gloss over management. If you have a slim profit margin, your system may still work if carefully managed. There are even cases where an otherwise unprofitable system will work if you “add” enough of the right kind of organization.

Gibbs energy has two terms, which I’ll simplify to “energy” and “entropy”. Energy is the basic “bang” of the system, sometimes obvious sometimes not. Entropy is the “organization” of the system. More organized means lower entropy. In the technical thermodynamics of the Gibbs equation, the energy and entropy terms are of opposite sign. This means, conceptually, “buying” organization using energy, or vice versa.

For a simple system, like an electrochemical cell, the terms are fairly straightforward to quantify. However, any system of real relevance, such as biological life or renewable energy, is much more complex, partly because it is less definite just where the boundaries of the system are. Though harder to quantify, it can be easier to conceptualize.

For example, a pure substance is more “organized” than a mixture, thus lower entropy. Picture a gold ingot sitting beside a heap of mine tailings. The gold is more “organized” than the original state, the mountain of ore. You can see that you have to “pay” energy, effort, management to get the gold. Incidentally, the whole scene, gold plus waste rock, is now less organized, higher entropy; but that’s another story.

Back to the case of the semiconductor hydrogen reactions. At the scale of the titanium dioxide (or whatever) particles, the system “goes”. Ultraviolet light hits the slurry and activates it, splitting water into hydrogen and oxygen. (This is not technically correct. It’s actually “electrons” and “holes”, and the chemical reactions may bypass hydrogen and oxygen. But it will serve for analogy.) So far, the practical use of such systems is to get rid of some undesirable organic pollutant. The oxygen produced “burns up” the pollutant, and a little hydrogen may bubble out.

But say you want to adapt these reactions to actually get a flow of hydrogen. Now you are faced with providing a feedstock of the organic material, as well as getting rid of the “burnt” carbon dioxide. Alternatively, you could let the slurry bubble out a mixture of hydrogen and oxygen — extremely explosive. Either way, your management costs have shot up. The larger system has to be much more “organized”. Is there still enough overall energy, enough “profit”?

Say you could magically get clean hydrogen. Hydrogen is a gas, and gases are inherently high entropy, relative to liquids and solids. The atoms are flying around more freely. To bring it to a more organized, manageable state, you can see you would have to expend effort. You could compress it into high-pressure tanks. You could liquefy it at extremely low temperature. This management “costs” energy, and cuts your overall profit.

Maybe you could chemically combine hydrogen with carbon to make a fuel that would be liquid at room temperature. That’s what gasoline is, and is why such fuels are so popular. But there is yet no practical way to do that. It would take extremely organized chemical reactions. Again, the management costs.

The closest that exists so far is the work of George Olah, which has come to fruition here. At first glance, this seems like the answer. You take carbon dioxide and water and you end up with the liquid fuel methanol. Methanol is a fair substitute for gasoline, not quite as high energy density because it contains some oxygen (it’s already part “burnt”). Poisonous, to be sure, if we drink it, and will readily kill anything it’s spilled on in any quantity. In this regard, similar to gasoline. But methanol is more readily biodegraded, once dilute enough.

But peek behind the curtain, using Gibbs energy, and you see how the Iceland plant is “cheating”. The energy is geothermal, essentially free. The carbon dioxide feedstock is volcanic gases, already concentrated; that is, lower entropy. To collect the same carbon dioxide out of the atmosphere would take enormous “organization” costs of energy. Maybe someday it’ll be feasible, but not now.

I want to make a nod to the supposedly “poor” efficiency of biological life, as photosynthesis. The number is usually quoted as a sad one or two percent, compared to our even crude solar cells at 10%. But look at the outputs.

Solar cells make electricity, which must be used at the same moment it is produced. By some reckoning, it has infinite entropy. The “management” term is our huge electrical infrastructure, with all its controls, including any storage. Yes, we have made it work, but it works best for steady inputs like hydropower or fuels we can burn at will. For “higher entropy” inputs that fluctuate, like solar and wind, we have to provide ever more organization.

As an aside, I saw a blurb about future cities harvesting their own energy, the skyscrapers coated in “quantum dots”. I love it! Those would presumably be molecule-sized solar cells, each feeding into the grid. What a wonderful futuristic image, compared to the clunky ones we have now: Blocky three-by-six foot panels, weighing some forty pounds, holding arrays of hand-sized solar cells. Most people don’t realize that if even one cell in the array gets shaded, the efficiency of the whole thing plummets. (This is why solar installations look so stark. There can be no shading anywhere.) This problem could be solved, but again at an “organization” cost of more complex electronics. The management of a cityscape of quantum dots would be, well, futuristic.

But, organization is clearly the way to go. Looking again at photosynthesis, the final output is a chemically stable solid, say wood or grain. It just sits there until you’re ready to use it. This is accomplished by the extreme organization of biological life. Life just “does” it for you.

Unlike transition metal oxide systems that need scarce, high-energy ultraviolet photons, plants can get by on abundant, low-energy red photons. Plants deal with the high entropy (extreme dilution) of their feedstocks without you even noticing. They scrape together enough carbon out of the fraction-of-a-percent carbon dioxide in ambient air. From this smidgen, they build huge forest trees, continents of waving grass, fields of corn. They quietly eke out their soil mineral feedstocks in a similar way. They don’t have to go halfway around the globe for strategic metals.

Each chlorophyll molecule is essentially your quantum dot. The highly organized biochemical machinery is in place to bring that energy out into a stable carbon-based compound, such as glucose, even at the cellular level. This is done with no extreme pH sulfuric acid or potassium hydroxide electrolytes, no nightmarishly high temperatures. This energy stock can be stored locally in the cell as starch, or transported. No batteries. No spinning flywheels. No explosive pressures or high voltages. When the energy stock is to be transported, the transport system is part of the package too, in the form of the plant’s vascular system, which runs on water.

We haven’t even talked about repair, recycling and replacement of defunct equipment. For built technology, these issues are routinely swept under the rug when looking at product lifecycles. Heavy metals from electronics leach into groundwater. Plastics spiral into the oceans. Even innocuous materials have be dumped and buried in landfills.

For biological life, the recycling was all worked out millions of years ago. Dead plants just rot. Before they die and rot, they live with dust, dirt, grime, muck, random weather conditions, scarcity, breakage, etc. All the things anybody who has ever tended machinery knows can be a full time job.

Again, for real-world systems, the “management” (entropy) costs are easier to conceptualize than to quantify. But when you look at all the entropy terms that living things routinely play ball with, a one or two percent overall “efficiency” is phenomenal. Biological life is the benchmark to beat.

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Yes, free will

The arguments that claim “there is no free will” use experiments like this: Transcranial magnetic stimulation (TMS) of the brain causes involuntary movements, such as twitching of a finger. Now, I enjoy a good non-sequitur as much as anybody:

 I took my friend Elmer out to the airport. I showed him how, by hacking into a certain relay on an airplane, I could get one of the wing flaps to lower.

 “Woah!” he said, “This makes it impossible to believe there was ever a pilot in control!”

 “Yes,” I replied, “That’s the only logical conclusion.”

 “And,” as he thought further, “There’s no such thing as flight!”

 “Quite correct,” I agreed.

 “Oh, and…” Now he was holding his head, and swaying, “So my memory. Of my vacation to Brussels, where I traveled by air… Was a complete delusion!”

 “The obvious truth,” I admitted.

 

Sorry. Yes, I know it was a failure. It falls short of funny. It’s stupid. Sorry.

But that is evidently the chain of conclusions that leads from these trivial neurological demonstrations to the sweeping philosophy “There is No Such Thing as Free Will.”

 

We find ourselves in a world built from ideas, created by decisions. Yet, there is no mechanism that turns those decisions into reality?

We find ourselves in a world where all sorts of things fly (bugs, birds, airplanes). It’s obvious they do. There are ways to stop them flying, like a flyswatter. Sometimes the wind is too strong for birds. Yes, terrorists crash planes. But it’s obvious, things fly.

The fact that a system can be sabotaged, hobbled, and hacked does not prove there’s no such thing as the system. Instead, it’s good evidence the system is the main event. The fact that flight can be thwarted doesn’t prove there’s no flight. The fact that free will has limitations is no proof it doesn’t exist.

By the Theory of Relativity, you can hold the perspective that an airplane did not fly from New York to Seattle. Rather, the craft remained stationary while the rest of the universe shifted around it. All the physics works out. But the stationary-airplane reference is useless, except for demonstrating the Theory of Relativity. For aeronautical engineering, you use a frame of reference where the plane flies.

Maybe there is another possible reference system than individual free will, such as that All That Occurs is the will of All. But still, intent creates reality.


 

We have a number of built in — I won’t call them “delusions”, rather “conveniences”. Cases where what we think our brain is processing, is different from what it actually is.

In vision, for example, our impression of smooth continuous motion. Certain people have a neurological breakdown, called “akinetopsia”, such that they lose this impression of continuity, and see only a series of snapshots. If you think about it, between normal blinking, eye-shifts, and perspective changes, that’s about all that’s coming in. So, we think our brain is processing motion, but it’s actually synthesizing it for us.

We develop a sense of familiarity about things. This goes so much without saying that we never notice until it glitches. Déjà vu, that sense of familiarity, yet somewhere we’ve never been. Or the opposite, jamais vu, loss of that sense when it should be there. What is “familiarity”? Memory, surely, but with a sense of time, memory-of-memory, a conviction that “this was this way before”. We know full well that most things were there before we saw them. But this fabricated sense-of-familiarity, in its normal working, gives us a convenient comfort that “this was this way before, for me.”

When we are enjoying a conversation, we sense it as a flow, happening in real time. We are not aware of the processing lags, both to decode speech and create it. We are not aware of processing at all, until we stray beyond a language we’re fluent in.

Incidentally, the case of not being able to choose not to understand speech in your native tongue is thrust up as “proof” there is no free will. I’m sorry. Limitations don’t disprove free will. Free will is not the same as godlike (or diabolical) omnipotence. You don’t have the “free will” to levitate a book by telekinesis. You don’t have the “free will” to hold your breath until you die. More’s the pity.

These examples, of visual smoothing, déjà vu, and conversational speech, all bear on how our minds play with time sense, so life works better. The no-free-will pundits make hay the most from some hair-splitting experiments in a similar vein. Supposedly, your impression of when you decided to take some action, like lifting your finger, occurs up to several seconds after the internal brain waves started, which lead to the action. Ok. So? It’s one more example of how our minds masterfully play with time, so the world makes more sense. We “backdate” our impression of when we decided, but still we decide.

Professional baseball players, with the highest batting averages, go up against a women’s softball pitcher — and she strikes them out! How? It turns out, one of the strongest predictors of success in pro baseball is simply — exceptional eyesight. The pro batter, without ever realizing it, has trained himself to read the body language of the pitcher. The batter knows how the ball is going to go before it ever leaves the pitcher’s hand. Indeed, it’s easy to show that, at the speed the baseball flies, there is no time to visually process its trajectory anyway. Yet, the batter swings, and a good percentage of the time connects. At least until he’s facing a pitcher with different body language.

So, because the batter used his well-trained neurophysiology, rather than conscious thought, to hit the ball, he never “willed” to hit it?

Another irrelevancy brought into the no-free-will harangue deals with that pesky time lag. Researchers introduce a time lag between the sound and the motion in a movie. Subjects shown the movie find it very annoying, when the mismatch is even a fraction of a second, much less than the delay between the brain waves that herald a decision and the impression of having made that decision. This is supposed to prove something.

This proves nothing, except we are used to how things work. First of all, it’s unlikely audio and video actually arrive in our brains simultaneously. We conceptually stitch them together, after allowing for processing delays.

You can perform the thought experiment of watching an unsynchronized movie, and easily imaging how irritating it would be. But imagine this. You are spending a relaxing weekend at a cabin on a lake. It’s mid-morning, and you are enjoying coffee, or the libation of your choice, on the porch by the lakeshore. You casually become aware of an interesting person at another cabin across the water. For convenience, I’ll say “he”. He’s splitting firewood. His big shoulders flex, and the axe comes down. The wood splits with a satisfying crack. The knock lightly echoes off the hills. You watch, cycle after cycle, and you do not find it irritating at all.

But wait. The other cabin is 1000 feet across the water. Sound travels about 1000 feet per second. So there is nearly a one-second delay between his muscular exertions and the resultant sound. Why no annoyance? Because you know from a lifetime of experience that’s how sound works, including the echo. In fact, the time delay contributes to the languid sense of space and atmosphere in the scene.

Ok, it’s my turn to fabricate neurological theories on that time lag between brainwaves and the sense of decision. I speculate that, like sound and echo in a tranquil forest, its purpose is to give a sense of light and space in the mind, the hallmark of a comfortable decision.

“Proof” does not consist in mashing together tenuously related concepts. Déjà vu does not prove, or disprove, past lives. Akinetopsia does not prove that existence is a puppet show. Neurological time lags have nothing whatsoever to say about free will.

apple seeds germinating


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Germinating fruit tree seeds

There is a huge amount of disinformation out there about how to grow fruit tree seeds. Rather than going into all that, this post is about how to do it.

This is not even an experiment. I’ve been growing tree seeds for decades, and I know how it will turn out. This is more a test, to demonstrate the techniques.

I saved a handful of apple seeds, from some random apples I used to make applesauce. Later, I’ll discuss differences in species and varieties, but ordinary apple seeds make a good demonstration.

I divided the seeds into three approximately equal batches, of about 23 seeds.

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The first batch was the “control”, or no treatment. I planted these in a pot of dirt, same as you might plant flower seeds.

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This was on January 22, 2016.

I kept the pot moist, in normal warm room temperature. At the end of the test, May 4, 2016, there was no difference. Not one had grown.

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If you try this with a large number of seeds, you may have one or two random seeds sprout, but this is not the way .

Next, the “freeze” batch, I put overnight in the freezer.

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The next day, I put them in a small ziplock bag with damp sawdust, and stored them in the refrigerator.

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I checked on them periodically. In this check on April 1, 2016, none have grown.

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At the end of the test, May 4, 2016, none had grown.

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Looking close, the moisture around the seeds is becoming milky. The seeds are starting to rot. They are dead, and have been since they were frozen.

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This is one of the misunderstandings. People hear that seeds need cold to germinate, so they freeze them. As if freezing will “break” dormancy, like shattering ice. No.

If seeds are completely dried, some species can survive deep cold, but it only holds them in suspended animation. It does nothing to make them germinate. Usually, it just kills them, as you see here.

For the “chill” batch, I put them in a ziplock sandwich bag with a little damp sawdust. I put this bag in the refrigerator. These seeds need moisture and oxygen to germinate. Polyethylene, the plastic most ordinary plastic bags are made of, is permeable enough to oxygen that this works fine. You can zip the bag closed so the seeds don’t dry out. You do not need to leave the bag open.

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In this check, on April 1, 2016, you can see that some seeds are starting to germinate.

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Germination is a gradual thing. I judged that a seed had “germinated” if the root tip coming out was longer than it was wide. So, on this date, I counted 3.

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In the next check on April 15, 2016, more had germinated. I replaced the sawdust with a damp paper towel, to make things easier to see. This works just as well as sawdust. If you don’t need the see the seeds, you can use peat moss, sand, soil, crumbled up autumn leaves, etc. If you’re doing a lot of seeds, you can mix them in the bag, and then plant the whole mix once the seeds are germinating.

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If you count the seeds, you will notice I did not put back the 3 that had already sprouted. The purpose was to demonstrate germination, not to grow the seeds. If you want to grow the seeds, you can plant them as soon as they sprout. They don’t need cold any more. In fact, cold only slows them down. This is natures way of easing the seedlings into springtime. Chill breaks their dormancy, but then the cold temperatures keep them growing slowly, so they don’t pop up and get hit by late frosts.

Going by my criteria, I did not count the seed in the lower right corner to have “germinated” yet, as its root was not long enough. So I counted 5 more germinated on this date, for a total of 8 so far. But as you will see, it makes little difference in the final tally.

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By May 4, 2016, all the rest of the seeds had germinated.

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Here’s the numbers on this test. None of the seeds grew except those in the “chill” treatment.

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The magic is holding the seeds at a temperature above freezing, but below about 40 degrees Fahrenheit (4 degrees Celsius). Your ordinary home refrigerator is the correct temperature range. How do you know? If it were too cold things would freeze and if it were too warm your food would go bad. If your refrigerator is working normally, it’s perfect to cold-treat seeds. This is what has happened when you cut open and apple and find seeds sprouting inside. The apple was kept in cold storage, and the period of refrigerator temperature satisfied the seeds’ chill requirement.

The seeds need to be imbibed with water, but not under water. Immersed in water, they would not get enough oxygen.

These are like the conditions a seed would find, buried in the surface layer of soil, through the winter. Even in continental climates, where air temperatures go extremely low, the soil a short distance below the surface seldom freezes so cold.

Here are the numbers on the “chill” treatment, with the dates translated into elapsed time. Chill requirements for plants are often expressed in hours, so I’ve included the elapsed time expressed as hours as well as days.

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Notice that nothing visible occurred for more than a month! It’s as if the seed has a little hourglass inside, which runs down while the chill conditions are met.  If it’s too warm, the hourglass stops. If it freezes, the hourglass stops. But after enough accumulated hours, the seed grows.

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Notice that this is not abrupt, but in most batches of seeds, once it starts it goes pretty quick. This is how nature hedges her bets. If some seeds came up too early and got killed, there would be stragglers to take their place. On the other hand, if the early ones got a good head start and took over more space, the next generation would drift towards lower chill. In tree species that have a substantial north-south range, local populations have adjusted themselves to the best chill requirement for their conditions.

Plants use the same chill mechanism to “know” when to leaf out. It correlates with seed chill. That is, for two of the same kind of plant, except with different chill requirements, the one that needs less chill to germinate from seed will need less chill to start leafing out each spring. All else being equal, it will bloom earlier too.

This explains why certain fruits are notorious for getting their blooms frosted. Peaches have a low chill requirement, and apricots even less. Evidently they originated in parts of the world with cold winters, hot summers, and not much transition (chill) in between. Brought to North America, where the weather has all sorts of wild swings, they get their chill requirement at the first breath of spring. They bloom out, then get snapped by late frost.

Why haven’t they adapted? They never needed to. If you grow these seeds, you will find them very “easy” to germinate. Everyone who ever cultivated them did too. The grower planted a bunch of seeds, and the first sprouts to pop up tended to get planted out in the orchard. This, of course, selected for low chill. The trees did well enough, and if the blooms got frosted too often, well, that region would not be known for apricot production.

If you wanted to develop, say, a late-blooming apricot, you could use this approach. Plant a lot of seeds. Say you want ten trees. As the seeds germinate, pot them up, but when the eleventh one germinates, pull up the first one and plant the eleventh one in its place. Keep on doing this. Eventually, you will end up with the slowest to germinate, high-chill individuals. It might take generations, but finally you would have a late-blooming apricot.

This chill technique for germinating seeds works for most mid-latitude tree crops: apples, pears, peaches, apricots, cherries, plums, persimmons, almonds, chestnuts, walnuts, hickories, etc. It may be hard to believe a tender root tip can break its way out of a rock-hard seed like a peach pit or a walnut, but it does.

Most trees that ripen their seeds in the fall need chill. These include ashes, beeches, and some maples such as sugar maple, Norway maple, bigleaf maple, and vine maple. Tree seeds that ripen in the spring tend to have no chill requirement. They are ready to germinate as soon as they fall. These include elms and certain other maples like silver maple, and red maple. A number of leguminous (bean family) trees, such as locusts and mimosa (Albizia), have no chill requirement. Instead, their germination is inhibited by a water-impervious seed coat.

This chill technique is sometimes called “stratification”. This is from a traditional method of putting layers (“strata”) of sand and seeds in flowerpots or lath-bottom boxes, and leaving these sunk in the ground over winter. You can see why it works. Winter moisture keeps the seeds imbibed. The upper layers of soil maintain the proper chill temperatures. The sand makes it easy to separate out the sprouting seeds when it’s time to plant them in nursery rows. If you do it this way, put bricks or something on top of your flowerpots, to keep squirrels from messing with your seeds.

Seeds that need chill will, of course, germinate just fine planted directly outdoors in the fall. However, there is liable to be a lot of grass and weeds also growing by spring when they come up. You may have a hard time spotting the seedlings, or remembering where they were.

If you want to grow a lot of seeds this way, plastic bags may be easier than pots. Collect up your seeds as they come along, and keep them so they do not completely dry out. For example, cherries ripen in early summer. As you use the cherries, put the pits in some loosely lidded container or a plastic bag with something to keep them a little damp, such as moist sand, soil, peat moss, dead leaves, or sawdust.

If you put them in the refrigerator in the summer, they are likely to have their chill requirement met by fall, and germinate as winter is coming on. If this is what you want, growing them indoors all winter, go for it. But for a more natural cycle, put your seeds in a plastic bag and bury it a little below the ground surface, or under some dead leaves or sawdust. Then, the seeds will stay at ambient summer temperatures until autumn, and their timers will not start running down yet.

Be sure you have your seeds buried before things freeze hard. One time, I had a bag of peach pits out on top of the ground, and a November cold snap went to single digits. All these seeds were killed, but the ones buried just a few inches were fine.

As autumn comes, the temperatures will start dipping into the chill range at night, and the seeds’ timers will start ticking. As the weather gets cooler, the seeds will accumulate more chill hours each day. In midwinter, the seeds may go slightly below freezing, and their timers will stop. But as spring comes, they will resume. As each seed germinates, it will start to put out a root. Keep checking them. If left too long, the roots will be all tangled together, and the seeds will be hard to separate out to plant.


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Germinating ginkgo seeds

I had never grown ginkgo (Ginkgo biloba) seeds before, so when I noticed them under a tree in late November, I collected some to investigate.

I had a ziplock bag with me, and filled it up with the “fruits”. Botanically, these are not fruits at all, but that’s another story.  It’s well known that these smell bad, at least when freshly fallen. The odor is described as rancid butter, or dog shit. However the autumn weather had been torrential rain, and the scent was all leached away.

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It was about a month before I got around to the seeds. Meanwhile, I left the bag outdoor so the “fruits” would stay moist in the wet autumn weather. On December 31, 2015, I started my experiments.

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The “berries” were single or in pairs, on stalks.

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When I peeled off the fleshy covering, inside were the seeds.

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I gently cracked them open.

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Inside were the kernels.

I knew that, botanically, ginkgo seeds are not like angiosperm seeds, where the embryo plant grows to a certain stage, and then various inhibitions come into play to keep it dormant. The ginkgo life cycle is more like a fern.

The brown dots on fern leaves shed microscopic dust-like spores. These drift on the wind. If a spore lands in the right conditions of moist soil, it grows into a prothallus. Prothallii are quite common, once you learn to spot them. Here is a picture of some that appeared in one of my potted plants.

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The dark green membranous thing in the lower right is the prothallus. It looks like a bit of seaweed washed up, that hasn’t dried out yet. It grew from a drifting spore, by the grace of drip irrigation watering that kept the soil continuously moist. The prothallii of most kinds of ferns can only develop in continually moist sites (this is where to look for them), though some cliff ferns have prothallii that can survive drying out.

With good luck, the prothallus grows to full size, which is only about a quarter inch across. When mature, it develops male and female gametes on its underside. When there is enough water, the male ones swim to the female ones, presumably sometimes to a different prothallus for genetic mixing. The fertilized zygote develops into a lump of cells, nourished at first by the prothallus. When this embryo plant gets big enough, it puts its first root down, its first leaf up, and grows into what most people recognize as a fern. The lighter green leaves towards the top of the photo are such a baby fern. It is growing out of a different prothallus than the lower right one, but it is behind the leaves and hard to see.

Other spore plants, like horsetails, also produce these gametophytes. “Gameto-phyte”, because it forms the gametes. The horsetail gametophytes I have seen are also green, but fleshier. Still other spore plants, like club mosses, supposedly produce lumpy gametophytes underground, but I have never seen them. The general plan is, the spore grows into a gametophyte, which only does two things: Produces gametes, and then nurtures the main plant till it gets on its own.

It doesn’t seem fair. The fern gametophyte has to eke out a living as a miserable prothallus, harvesting enough sunlight to grow and start the next generation, while desperately living on the edge of death by desiccation. But the main fern plant is big and robust, with roots and tall fronds, and all. Why couldn’t it help out the next generation of gametophytes with some of its bounty?

This is evidently what ginkgoes have done. Instead of casting spores to the wind, the ginkgo holds them on little stalks. As a spore develops into a gametophyte, the tree feeds and shelters it. Instead of having to live free or die, the ginkgo gametophyte has a pampered life. How the gametes get to it from a different gametophyte is another story, but the hint is: Pollen.

So, I looked at these ginkgo kernels, and I thought: When I want to grow ferns, I get the spores, and set up moist mellow conditions, and by and by they to grow into prothallii. Then I just wait. In their own sweet time, they get around to the gamete thing, and then start with the lump of cells. Once the first fern leaf appears, I’m home free.

So, here with this ginkgo seed, it’s all been done for me. No fragile prothallus to fuss over. This gametophyte doesn’t have to be green because it doesn’t need photosynthesis. It was well provisioned by the tree. So, instead of thin and membranous, it’s fleshy and packed with stored food.

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I sliced some of the ginkgo kernels open, and there were the developing plant embryos. This was exactly analogous to the lump-of-cells stage of a fern plant on its prothallus.

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The ginkgo plantlets were different sizes. Some were about half the length of the seed, but some were as short as a quarter the seed length.

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Some gametophytes had no baby plant at all. I guess sometimes the male ginkgo is shooting blanks.

So, I thought, maybe it’s the same as growing ferns. You just set them up and let them take their own sweet time. They don’t need light in this case, but they probably want to be moist.

I divided my ginkgo seeds into three groups. I put them in ziplock sandwich bags with damp sawdust. Probably sand would have worked as well, or moist leaves, or even torn-up wet strips of paper.

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One bag I kept about 40 degrees. This was outdoors in an unheated garage. It might have occasionally got frosty, and sometimes as warm as 50 degrees.

gb110_60degbag

One bag I kept about 60 degrees. This was indoors, on the floor of the basement.

gb120_80degbag

One bag I kept about 80 degrees. This was in a plant growing room with warm lights.

On February 3, 2016, I checked on them. This was after about a month, 34 days. All three had been going for the same length of time.

gb130_40degseeds

I picked three seeds at random out of the 40 degree bag. The embryos had grown some, but not much. They averaged about half the length of the seed.

gb140_60degseeds

I picked three seeds at random from the 60 degree bag. Here, the embryos were definitely bigger, about three fourths the length of the seed. If you can see, in the middle one, the root is starting to push out of the gametophyte.

gb150_80degnuts

When I came to the 80 degree bag, I did not pull them at random. I grabbed the first three that were obviously clambering to get out.

gb160_80degseeds

It looks like ginkgoes have something like hypogeal germination. That is, the seed does not get pulled up above ground. The embryo elongates to push the leaf bud outside the seed, along with the root, and then a shoot grows up from that. The upper ends of the “cotyledons”, or whatever they are, stay inside the seed, to continue feeding from the gametophyte.

So, it appears to me that ginkgoes do not have true seed dormancy, as angiosperms do. To avoid coming up too early, in the midst of winter, the ginkgo embryo simply develops very slowly, as long as things stay cold. Instead of counting chill hours, they just pace themselves. When spring comes, they speed up. The warmer it gets, the faster they grow.

If you want to grow ginkgo seeds, just keep them warm, and they’ll sprout. They absolutely do not need to be frozen. Deep freezing would probably kill them. Drying out would probably kill them too. After all, they are just gametophytes.


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Germinating mimosa seeds

I thought that the main germination inhibition for mimosa (Albizia julibrissin) was the water impervious seed coat. This is an experiment to check that.

I found some mimosa pods that had just fallen from the tree. Their structure was papery valves (the flat sides), with wiry reinforced edges.

20151124_080445_mimosa_pods

Mimosa pods

It was evident their dispersal mechanism is to be blown about till the wiry edges wear out, allowing the valves to peel apart and drop the seeds. This goes along with the idea that the seeds are blocked from germination until their hard coats are breached, either from erosion by gritty soil, or long rotting in humus.

I took out ten seeds.

ten mimosa seeds

Ten mimosa seeds

I put them in water to soak.

ten mimosa seeds soaking

2015-11-24 08:10

About 24 hours later, two of the ten (20%) were imbibed with water.

20 percent imbibed by 2015-11-25 06:46

2015-11-25 06:46

This verified the seed coat was impervious enough to water to prevent absorption.

seeds, imbibed and not

Compare imbibed to not imbibed.

Breaching an impervious seed coat is called “scarification”. There are various ways to do it to bulk seeds; but for individual seeds you can use a file, knife, or sandpaper.

metal file

metal file

Here, I scratched seeds on a file.

scratching a seed on the file

scratched seed

I rubbed till the lighter colored interior showed through.

seed coat filed through

Seed coat filed through

I also nicked some seeds with a utility knife. I avoided the very tip of the seed, in case I might damage the embryo root, though seeds like this often protect their incipient root by embedding it somewhat back in the embryo.

Here is a scarified seed beginning to imbibe. This seed was both scratched and nicked. The flap towards the top is the nick.

seed beginning to imbibe

2015-11-25 09:19

The water absorption is a chain reaction. As the interior swells, it disrupts the seed coat from the inside, and allows still more water to enter.

Here is the same seed fully imbibed.

same seed fully imbibed

2015-11-25 12:05

The water absorption goes quickly after the seed coat is breached. Here, the seed has become fully imbibed after only a few hours. Many of the intact seeds were still dry inside after twenty-four hours soaking, and could have remained so indefinitely.

In order to closely observe the seeds, I put them in a standard germination test setup, rather than planting them in soil.

Here they are along the top of the folded, wet paper towel.

seeds on wet paper towel

I close the fold, and rolled this up on a chopstick.

seeds rolled up in wet paper towel

I held this, in light, at warm room temperature, about 80 degrees F.

seeds rolled in paper towel, standing in jar of water

2015-11-25 12:15

Within 48 hours, I had 100% germination.

ten mimosa seeds germinated

2015-11-27 09:01

close up of germinated seeds

close-up

This demonstrates that mimosa seeds’ germination requirement is primarily imbibation with water, and warm temperature. There is no inhibition by light, and no chilling requirement.

This explains why mimosa seldom volunteers in Portland. The time of year when temperatures are warm enough is also the driest weather. Seedlings that germinated in early summer would fail from drought later.

 


2 Comments >

Botanical term: “Imbibe”. Most seeds can remain dry-dormant for long periods of time. When they take in moisture to capacity, they are said to “imbibe” it, or to “become imbibed”. Some seeds, like the beans used for food, noticeably swell. Others, like tree seeds such as apples and maples, do not look much different. In these cases, the main change is internal texture. The plant embryo, which was hard and brittle when dry, becomes leathery or soft.

The state of “being imbibed” with moisture is distinct from simply “wetted”. Seeds with an impervious coat may not become imbibed, even when soaked in water. On the other hand, many seeds will become fully imbibed when placed in soil that seems scarcely moist to the touch.


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Cure for depression?

  • Effective, though controversial, treatment for depression is electroshock.
  • Alternative natural “brain sparker”: Exercise?
  • What kind of exercise: Sufficient to have to breath harder?
  • Links with: Spiritual traditions and their breath exercises?
  • Links with: Jumping-into-cold water, which causes hyperventilation by Cold Shock Response?
  • Links with: Mammalian Diving Reflex, cold water on the face, and especially up the nose?

– For feedback on these ideas:
Do you know anyone who stays depressed, who exercises strenuously enough to breathe harder? Or has a spiritual practice of breath exercises? Or uses cold water in these ways?