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  • There's a good chance you know, the cats and dogs on your block better than you know, the trees and flowers.

  • And hey, that makes sense.

  • No judgment here.

  • After all, plans don't greet you on the sidewalk.

  • Getting fights with raccoons are sneak up on you when you're walking home in the dark.

  • They keep a low profile, but really, plans are amazing.

  • They give us food and oxygen, they decorate our homes, and they're also really fascinating organisms.

  • We've talked about plans a ton on this channel and thought it was about time to compile some of our favorite episodes about, um, speaking of time, here's Hank to explain how plants can tell what time it is because, you know, apparently that's something they can do.

  • Plants don't have brains is probably not news to anyone.

  • Plans also don't have muscles or anything resembling a nervous system, and yet they can move in some plants.

  • This is actually pretty dramatic, think Venus flytrap, But there are tons of plants that move more slowly, and they do it in time with the coming of day and night.

  • So how do they move and how do they know when to do it all without a brain Ernie that other stuff.

  • Many plants, such as members of the legume and wood sorrel families, tuck their leaves in at night.

  • We don't totally understand how this happens, and we have almost no idea why.

  • But scientists have identified some of the players involved.

  • The process of how plants tuck themselves in at night is called nicked.

  • A nasty, nasty movements are a plant's movement in response to a stimulus that doesn't occur in a particular direction.

  • Believes don't follow the moon or anything.

  • They just droop.

  • Temperature change plays a role in this response.

  • The cooler night air can help signal the plant's reaction, and the warming sun in the morning does the opposite.

  • But it gets quite a bit more sophisticated than that, involving not just temperature changes but several different types of chemical reactions.

  • One player in this process is a molecule called Fight a chrome, which absorbs light fighter.

  • Crume participates in a reversible chemical reaction, meaning it doesn't just react to form a product and then stop.

  • Instead, it can switch back and forth between two different forms, depending on the conditions.

  • These two forms are called P R and P fr.

  • Initially, fighter Krome takes the form of PR so called because it absorbs red light, which there's more of during the day when the sun is out.

  • As PR absorbs red light, however, it is converted into P F R, which absorbs far red light instead, basically the less intense wavelengths as the sun sets absorption of far red light causes P f R to convert back to PR.

  • Some of it will change back over time in the absence of any light as well, which means that the fight across automatically cycles back and forth between forms, depending on whether it's day or night.

  • He's changing.

  • Forms of fighter chrome are important in structures called pull vine I Ah Provine Us is a region of bulbous tissue at the base of a leaf that acts as a flexible joints like ah, plant elbow.

  • When enough P f r is present in the pool finest, the plant pumps water to a specific section of the joint.

  • The change in water pressure within the cells, called turker pressure, basically flexes the joint like a muscle which bundles the leaves up for the night when the chemical reaction reverses the Turker pressure shifts back.

  • Additional leaf chemicals called leaf closing and leaf opening substances also play a part in nighttime well, belief, opening and closing.

  • There's a lot of variety in these chemicals, but the general idea of oscillating chemical reactions is similar in the same way many flowers open in the morning and close at night for reasons that are even more poorly understood.

  • It might be to conserve a flowers sent to protect their nectar to keep Paul and dry.

  • Some other reason, but the mechanism might be similar.

  • Pedals, after all, are just a type of leaf.

  • This isn't the only kind of day and night plant movement either.

  • Many species actively follow the sun during the day in a process called heliotrope is, um unlike Mastic movements, trope ISMs are plant movements that are oriented in a specific direction.

  • Heliotrope is, um, can help leaves get the most possible.

  • Some lights, often heliotrope ism in leaves, is also controlled by turker pressure in pull vine.

  • I if you wanted a lot of new terminology all in one sentence, so this gives the leaves can move continuously to track the sun throughout the day.

  • Rather than just opening and closing, and some flowers followed the sun, too.

  • It seems tohave a few benefits, like providing a nice warm place for pollinators and helping the plants seeds develop.

  • But many heliotrope pick flowers have no pull vine.

  • I young sunflowers instead turned to face the sun by growing their stem on one side at a time.

  • It's not totally clear what chemicals the sunflower is used to sense sunlight.

  • But the changes in stem growth appear to be governed by a hormone called oxen, which in this case tells certain parts of the plant to grow in response to light.

  • The stem of the sunflower grows faster on the side.

  • That gets less light, thanks to a higher level of oxen, activity on the shady side that tilts the developing flower toward the sun at night and the absence of sunlight.

  • Sunflower stems reorient themselves to face east again, and in the morning the light directed growth process resumes.

  • But sunflower stalks don't keep growing forever.

  • Solar tracking only happens in young sunflowers.

  • Once they're fully mature, the flowers face east and never move again.

  • So now you know how to tell what direction things are if you're in the middle of a sunflower fields, and you also know that plants don't need brains or nervous systems or muscles to respond to their environments as long as they've got chemistry on their side.

  • And they're more sophisticated about it than we think able to keep track of time and act appropriately, which is pretty smart.

  • So plants know when the sun rises and sets, that means in my part of the world, they know that the sun is starting to set earlier and things air cooling down around our office.

  • We've started keeping the windows and doors shut to block out the winter chill, but if you're doing the same thing at home, things might start to feel a bit stuffy.

  • So in place of that fresh air wafting in with the breeze, could you just keep a few house plans to purify the air?

  • Instead?

  • Here's what the science says.

  • It seems like every workplace has that one person who swears that the potted spider plant sitting on their desk has an almost magical ability to purify the air in the office.

  • Are they actually onto something?

  • There is evidence to show that plants can remove pollutants from indoor air, but a single potted plant probably won't go the distance.

  • If you've heard that bringing plants into your home or office will improve your indoor air quality, you probably have a study conducted back in 1989 by NASA to thank for that.

  • The goal was to test whether a variety of types of indoor plants could be used for air purification, both on Earth and in space.

  • The plans were put into sealed containers and the air pumped full of chemicals, including benzene and formaldehyde.

  • Those chemicals fall under the broader umbrella of volatile organic compounds, or VO ces, some vo CES air known to cause health issues like headaches or liver and kidney damage, and their noteworthy as indoor pollutants because household products and building materials can give them off.

  • The plants were kept under controlled conditions with plenty of light on water, and the air quality was measured over a 24 hour period, the study found.

  • The majority of plants included in the experiment removed much of the benzene and formaldehyde from the container, Lancer, thought to remove pollutants from the surrounding air by absorbing the gases through their leaves, and roots, with some possible help from the microorganisms in the soil.

  • So that's it, right?

  • House plans help clean the air well, not quite Leader study is doing.

  • Similar experiments have yielded mixed results.

  • A 2009 study tested 28 varieties of indoor plants and found four that we're the best at capturing every V O.

  • C.

  • The researchers throughout so plants definitely can remove some pollutants in a laboratory test chamber.

  • But these idealized lab conditions don't exactly represent the air in your office.

  • Stuff like the amounts of light water and air circulation are all going to be different.

  • On top of that, the lab plants were purifying the air in a small area.

  • Some of the chambers in the NASA study were less than a cubic meter in volume.

  • That means for the same amount of purification to happen in your house, you would need an indoor rain forest.

  • One critic of the NASA studies suggested that to get the same effect in a typical home, you'd need about 680 separate plants.

  • There have been a handful of other studies investigating the effects of plants on indoor air quality, but at least one review, published in 2014 has attempted to take stock of the existing research, and it concluded that while lab based studies generally show some effect, not many have been performed in living spaces, and the ones that have been done haven't yielded a consensus.

  • So don't count on your poor desk fern to fix all of your indoor air problems, so a single spider plant on the window sill isn't going to fix that stuffy air.

  • But even if plans aren't doing that much for you, many of them are looking out for each other in the wild.

  • Plants are constantly communicating, and many of them have a lot to say.

  • Here is how plans talk to each other with the help of some friendly fun guy.

  • The Internet connects more than half of the world's population through an invisible web of servers, computers and devices.

  • It's changed our lives and countless ways by allowing otherwise separated people to interact and by providing access to vast amounts of information.

  • But humans aren't the only organism on the planet with an invisible, interconnected network.

  • Well, plants may seem like isolated, solitary individuals.

  • They're capable of communicating with each other, sometimes over considerable distances, all thanks to their special relationship with fun guy.

  • Nearly all plant species we know of have a mutually beneficial relationship with soil fund guy called Mike Arise E Michael Rises, a growing network of small branching tubes called mycelium that extends through the soil, including inside or around plant root.

  • And these allow the fun guy to absorb nutrients from the soil like nitrogen and phosphorus, which plans struggle to extract so they basically barter in exchange for those hard to get nutrients.

  • The plants trade the fun guy carbon in the form of sugars, and ultimately together both can thrive when they otherwise wouldn't.

  • Just symbiotic relationship between plants and fungi was discovered in the early 19 hundreds, but it wasn't until 1997 that we understood just how deep this underground network goes.

  • Ecologist Suzanne Sam Ard had a hunch that plans weren't just sharing nutrients with fungi but also with each other.

  • To test her hypothesis, she and her colleagues infused trees in a forest with a traceable radioactive form of carbon and later took samples from neighboring trees, and it turned out that many nearby trees had the radioactive carbon, too, proving that plants could send nutrients back and forth to one another.

  • Not only that, they seemingly distributed the nutrients where they were needed.

  • Most plants need light energy to turn carbon dioxide and water into sugar and oxygen, thanks to that magical process called photosynthesis.

  • So those in shade have less sugar to go around.

  • Some art found that these sheeted energy deficient trees ended up with more of the radioactive carbon than their sunbathing counterpart.

  • So it's basically the plant fungi equivalent of feeding The hungry continue to research into these underground networks called common Mycelium Networks has revealed that plans are not only able to gain access to more nutrients, they can also engage in sophisticated communication by talking chemically through my Celia.

  • And it turns out they're saying quite a bit.

  • Generally, any seedling that's plugged into the common Mycelium network, or CME N, has a higher likelihood of surviving.

  • And the plants that air online are generally healthier to researchers think this has to do with having access to an early warning system.

  • When a plant's attacked, it releases chemicals that tell nearby plant something bad is coming their way.

  • This communication happens with airborne compounds but also through a CME N and other plants.

  • Heed this warning.

  • For example, when tomato plants are connected by a CME N and one plant is attacked by a pest, nearby plants will activate their defences before the pest reaches them.

  • Scientists are only just starting to understand how important these plant networks are.

  • They've discovered that entire forests can be interconnected, but, like with our Internet connectivity throughout, an ecosystem isn't evenly distributed.

  • Older, larger trees are more connected, kind of like some servers in the human Internet, these highly connected trees air called hub or mother trees.

  • They have big route networks that host a greater diversity of Mike Arise, all Fun Guy, and that allows them to interact with a lot of other plans.

  • They do play favorites, though.

  • Scientists have shown that they can send care packages of extra nutrients to their kin to help them survive, which is how they got the mommy moniker.

  • And they can also help forests transition during times of change.

  • When they're injured or dying, they release a surge of carbon into the network, which nurtures the next generation of trees, even if they're a different species.

  • Of course, no Internet is complete without hackers.

  • Some plants can claim territory and influence community dynamics by sending toxins into the CME.

  • N black walnuts will use these networks to release toxins into the soil.

  • For example, those that are immune to the toxins thrive, while others struggle or die off and harmful worms, parasitic plants and fungi can find their way to the plants they target by following chemical trails emitted by the micro rise E underground.

  • It's amazing to think that this chemical information superhighway was right below where noses for eons and yet we had no clue.

  • But now that we can finally plug in, it might just help us connect to the planet's flora in much more constructive ways.

  • Knowledge of this interconnectivity is helping improve our relationship to plans, including things like forest conservation and agriculture.

  • For example.

  • Preserving the highly connected mother trees from deforestation ensures Michal Raziel fungal diversity and helps forest regrowth happen more quickly.

  • And farming and soil with a CME n means plants can warn each other of invading pests, which might reduce the need for pesticides like what the human Internet, the Internet of the Earth, increases security awareness and knowledge for those connected to it, including us.

  • So plans are just talking to each other all the time.

  • And honestly, that kind of worries me because some plants are keeping really big secrets.

  • Here's Hank with a terrifying secret about bananas First, the good bananas are healthy, packed with nutrition and energy.

  • They fit in your hand and give nice little cues when they're perfectly ripe and are easy to peel and eat.

  • Shocking statistic.

  • The banana is Wal Marts.

  • Number one selling item, not the potato chip.

  • Not Coca Cola, not 50 shades of grey bananas.

  • They appear to be so perfect for human consumption that Kirk Cameron attempted to use them to prove the existence of God.

  • Of course, this banana was not created by God or really even nature.

  • Bananas, at least the ones that you see at the store were created by people.

  • Don't get me wrong.

  • There are wild banana plants, lots of them.

  • They're native to South and Southeast Asia, and there are dozens of species and thousands of varieties.

  • They're just not the ones we eat.

  • Some of those species, as you might suspect, have seeds.

  • That's what fruits are their fleshy bodies containing seeds.

  • So you might wonder, why have you never eaten a banana seat?