Category
📺
TVTranscript
00:00Satsang with Mooji
00:30The Tatlamakan Desert in northern China.
00:36A constantly shifting landscape of sand.
00:43Temperatures that swing from minus 20 to more than 40 degrees centigrade.
00:52And most critically, almost entirely, without rain.
01:00The Tatlamakan Desert in northern China.
01:06Yet, here on the dunes...
01:15...a Euphrates poplar tree.
01:25And it's not alone.
01:29Some of these trees have lived here for a thousand years.
01:36They have exceptionally long roots with which to collect water.
01:42And what is more, those roots are connected to neighboring trees.
01:45So that if one strikes water, others can share it.
01:54In every desert, across the planet, plants have found ways to not only survive, but flourish.
02:02This is the Grand Desierto of Mexico and the United States.
02:20The Grand Desierto of Mexico and the United States.
02:24These dunes may appear to be totally barren.
02:40In fact, they are full of life.
02:42In the sands beneath my feet, there are seeds of many different kinds.
02:49In fact, you could say that the dune itself is one great seed bank.
02:54And when it rains, it bursts into life.
02:57But rain may come only once a decade.
03:08And even then, the long-awaited storm may be very brief.
03:12So seeds must respond immediately.
03:20This is sand verbena.
03:22This is sand verbena.
03:36It can grow from a seed to a sweetly-scented flowering plant in just a few weeks.
03:42Primroses and many other plants soon join the race to flower before the sand dries.
04:00Desert blooms like this, however, are rare.
04:07This is the first year for 20 years.
04:12The combination of vibrant color and powerful scent attracts migrating pollinators,
04:23such as these painted lady butterflies,
04:26which fly into the middle of what were only recently barren dunes.
04:33Everything is rushing to complete their lives before the moisture has gone.
04:43Such spectacular blooms transform deserts all around the world.
04:51From the Atacama in South America...
04:56To the dusty plains of Southern Africa.
04:57From the Atacama in South America.
05:03To the dusty plains of Southern Africa.
05:09of southern Africa.
05:29The rain in deserts, however, never last long.
05:33And all too soon, the flowers wither and die.
05:39But not before they've produced the next generation.
05:52The seeds that will now wait in the sand for the next rains.
06:02In the Sonoran desert of North America,
06:04the huge saguaro catcli have a different strategy.
06:09They store water in quantity and can live to a great age.
06:16But in their early years, they are extremely vulnerable.
06:20This little saguaro cactus is about ten years old.
06:28When they're really small and growing out in the open,
06:32there's a real chance that they may shivel up and die.
06:36But this one has been lucky.
06:39It's been growing in the shade of this mesquite tree.
06:43And it's got a very good chance of surviving to maturity.
06:47The young saguaro is protected by the mesquite's branches.
06:53They halve the amount of scorching sunlight reaching the cactus.
07:01And so keep it cool.
07:05And the mesquite's extremely long roots draw up water,
07:09bringing it within reach of the young saguaro.
07:13So the mesquite is known as a nurse plant,
07:21and a very effective one it is too.
07:25In fact, this particular mesquite
07:27has already nurtured seven young saguaros
07:31over the past 30 years.
07:33As a young cactus grows,
07:38it needs the protection of its nurse plant,
07:40not only from the heat,
07:42but from the other hazards of desert life.
07:46Temperatures can drop to minus 10 degrees overnight.
07:52And very occasionally,
07:56it even snows.
08:00If the water stored inside a young cactus should freeze,
08:11the cactus will die.
08:17But the nurse plant traps a blanket
08:19of slightly warmer air around it,
08:21just enough to keep it alive.
08:27Eventually, saguaros outgrow their nurses.
08:30But by that time,
08:32they are robust enough
08:33to face the elements by themselves.
08:40No matter how old a desert plant is,
08:42water is always precious,
08:45whether gathered from melting snow
08:53or a shower of rain.
08:54So, cacti have developed extraordinary adaptations
09:03that enable them to not only collect water,
09:06but to retain it.
09:09Instead of leaves,
09:14which would lose precious moisture through evaporation,
09:18they have spines.
09:19The spine has a tiny pad at its base
09:24where the water is absorbed.
09:29And then stored in the great swollen trunk.
09:35A large saguaro can hold 5,000 liters of water
09:39and is able to do so because it has another special adaptation.
09:55The ridges on its surface are like the pleats on an accordion.
09:59They allow the saguaro to change its shape.
10:04After rain has fallen,
10:06the pleats expand
10:07and the saguaro fills up its water tank.
10:10In the dry times,
10:17it uses its water to grow,
10:19produce flowers,
10:21and eventually,
10:23siemens.
10:27Fully loaded with thousands of liters of water,
10:30this saguaro won't need to drink a single drop for another year.
10:34But such valuable stores of water attract thieves.
10:43Now the spine's function changes from collection
10:48to guarding.
10:52The spines of some species are a quarter of a meter long.
10:55Others are needle-like barbs that grow in clusters
11:07and easily break off in the skin of any animal that touches them.
11:12But perhaps the most vicious cacti belong to a group called the choirs.
11:19This is called a teddy bear choir
11:23because of the thick coating of spines on it.
11:27But don't be deceived by the name.
11:29There is nothing cuddly about this particular teddy bear.
11:33In fact, it's the most dangerous plant in the desert.
11:37And I wouldn't dream of putting my hand anywhere near it
11:41without proper protection.
11:45Brush against it.
11:48This can hap-
11:49Ow!
11:50This can happen even with this glove on.
11:52One of them has just gone through.
11:53I can feel it.
11:54It's quite painful.
11:58Look closely at the spine,
11:59and you can see very clearly why they're so dangerous.
12:04Each is like a splinter of glass, sharp enough to pierce flesh.
12:10And they're covered with backward-pointing barbs.
12:14So getting them out, even with a pair of pliers, is quite hard.
12:19This is not pleasant at all.
12:22It won't come off or without.
12:26Oh, look at that.
12:30It's hard to imagine a more aggressive defence than this.
12:33And it makes both the plant and its buds virtually invulnerable.
12:50Most animals know to keep clear.
12:53Cholla buds grow like tiny barrels from the top of the adult plant and then drop off.
13:06If the young Cholla put down roots here, it would compete with its parent for water.
13:22Night falls.
13:23Night falls.
13:25And this one is on the move.
13:38The pack rat.
13:39She knows how to deal with the Cholla.
13:41Night falls.
13:47She avoids the spines by gripping it at the place where it broke off from its parent.
13:59And she works fast.
14:03There are pack rat hunters here.
14:11She uses the Cholla to build a spiny wall around her nest.
14:19The flesh of the Cholla supplies her with water.
14:41And the severed spines further reinforce the defences.
14:45This Cholla bud might be next.
15:06But one accidental nudge...
15:08...and it escapes.
15:38The bud starts to put down roots.
15:53So the choya, thanks to the pack rats,
15:56finds new territory and sets about claiming it.
16:08Few plants deal with the problems of desert living better than cacti.
16:16There are almost 2,000 different species of them.
16:21They're spread across the deserts of the American West,
16:24from Arizona all the way to Mexico and beyond.
16:29In South America, the ice-covered peaks of the Andes act as a rain barrier,
16:41beyond which lies the world's driest desert, the Atacama.
16:47In the desert world, water thieves can come in many forms
17:00to exploit even the smallest chink in a plant's defence.
17:05One of the strangers travels within the gut of a fruit-eating mockingbird.
17:23These are the seeds of crystarix.
17:27They're kind of mistletoe.
17:29Their goal is the water inside this hedgehog cactus.
17:40Using the spines as anchors, the seeds start to germinate.
17:48Each produces a long probe with which to try and locate the cactus's skin.
17:54For most, that's a stretch too far, and they perish.
18:05But for this one, the cactus's surface is within reach.
18:09It clamps onto it with a special sucker.
18:25And then waits for darkness.
18:30At night, the cactus opens its paws in order to respire.
18:34Oxygen goes out, carbon dioxide goes in, and so does trystarix.
18:51Once within, its tissues spread throughout the body of the cactus,
18:56sustained by the precious store of water that they find there.
18:59Then, a year later, it breaks through the cactus's skin...
19:09...and bursts into flower.
19:12Hummingbirds come to drink their nectar...
19:13...and pollinate them as they do.
19:14Hummingbirds come to drink their nectar...
19:15...and pollinate them as they do.
19:16Hummingbirds come to drink their nectar...
19:17...and pollinate them as they do so.
19:18Hummingbirds come to drink their nectar...
19:19...and pollinate them as they do so.
19:20Hummingbirds come to drink their nectar and pollinate them as they do so.
19:50And then, to complete the cycle, Tristerix produces hundreds of white, eye-catching seeds ready to be carried away by a bird to invade another cactus.
20:06The Karoo Desert in Southern Africa.
20:20And although it may look bare, its rocky ground contains an unrivaled variety of plants that, one way or another, store water in their tissues.
20:33They belong to many different families, but, as a group, they're known as succulents.
20:40Some are small and low and barely distinguishable from their surroundings.
20:47These look like little pebbles.
20:54They resemble them so closely that animals, which might be only too glad to steal their water, just pass them by.
21:03They resemble them so closely that animals, which might be only too glad to steal their water, just pass them by.
21:09When rain does fall, they absorb it and quickly expand.
21:24When rain does fall, they absorb it and quickly expand.
21:31But even this doesn't spoil their disguise.
21:33They just look like larger pebbles.
21:38Nor are they green.
21:40The cells on their top surface are transparent and allow sunlight to pass through.
21:45Deep within and out of sight are the green cells where photosynthesis occurs.
21:54The process which uses this light to make food for the plant.
21:58When the time comes to reproduce, however, the stone plant abandons its disguise.
22:28And now it blooms.
22:43The flowers open and close every 24 hours.
22:47So for a few dangerous days, the plant advertises for pollinators before returning to life as a pebble.
23:17Some desert plants have developed a very different way of attracting pollinators.
23:26This is stapelia.
23:29It produces what is perhaps the desert's strangest disguise.
23:34It uses water stored in its stems to grow buds the size of tennis balls.
23:47The flower, once opened, is called a desert starfish.
24:08Instead of releasing millions of loose pollen grains as most flowers do,
24:13the desert starfish produces them packed in five tiny sacks.
24:21But if its strategy is successful,
24:24just one of them will produce hundreds of seeds.
24:31And this depends on deception.
24:37The flower appears to have hair.
24:39Wrinkly skin.
24:46And it produces a stench like the carcass of a dead animal.
24:50And when a carrion fly investigates,
25:04the flower clumps a tiny sack of pollen to its proboscis.
25:10The flower clumps a tiny sack of pollen to its proboscis.
25:22It's not easy to feed with such encumbered mouth parts.
25:28But try as it might, the fly can't get rid of it.
25:31And it's still there when the fly leaves to try and feed from another bogus carcass.
25:46This time, however, when its clamped-up proboscis slots into the flower,
25:50the pollen sac is released.
26:00With pollination complete, the fly is no longer needed.
26:08And just as well.
26:09Some deserts can be so dry that plants must find techniques of surviving for long periods without any water whatsoever.
26:25One of them is to grow extremely slowly.
26:28And few plants grow more slowly than this one, the creosote bush.
26:37It is inactive for most of its life.
26:40And only wakes up and grows for a brief period.
26:43If and when there is a fall of brain.
26:50I've seen evidence of this grow slow strategy for myself.
26:55Forty years ago, I came here to California's Mojave Desert to visit one particular plant.
27:04An individual creosote bush tends to spread not by setting seeds and producing a new generation,
27:11but by sending out new stems around its base.
27:16This plant started growing between 10 and 12 thousand years ago.
27:22That was in 1982.
27:29Since then, careful measurement has shown that it has increased its size by less than one inch.
27:40Its ability to endure is truly extraordinary.
27:43So efficient is creosote collecting what little rain falls here,
27:53that few other plants can compete with it.
27:56As a result, over the last 12 thousand years,
28:00it's come to completely dominate this landscape.
28:02The Chihuahuan Desert in North Mexico.
28:09Here, one particular plant plays the waiting game so well,
28:16that it spends much of its life looking dead.
28:20And certainly not worth eating.
28:22And it can survive like this for a decade.
28:25This is the resurrection plant.
28:26This is the resurrection plant.
28:27Here, one particular plant plays the waiting game so well,
28:29that it spends much of its life looking dead.
28:33And certainly not worth eating.
28:34And it can survive like this for a decade.
28:40This is the resurrection plant.
28:53It's a kind of moss.
28:57It barely has roots and it certainly can't store much water.
29:02But it can travel.
29:04After a particularly long drought,
29:14it breaks away from its roots
29:19and becomes a tumbleweed.
29:27Blowing across the desert,
29:29it can travel a mile in a week.
29:34With luck, it may find water.
29:44Just a shower of rain can bring it back to life.
29:53As its fronds soak up the water, they unfurl.
30:04In its protected center, it still has green cells,
30:15which absorb both the water and sunlight
30:18and rapidly produce the food it needs to resume its growth.
30:28It will grow for just as long as there is moisture.
30:35But when that disappears,
30:38it closes up once more
30:41and resumes its travels.
30:43Here in the canyon lands of Utah,
30:44lives a plant that has developed a finely balanced relationship
30:48with the animals with which it shares this dramatic desert.
31:10Rain does occasionally fall here,
31:12and turns dust into mud.
31:21But that doesn't last long.
31:24A brief window of opportunity opens.
31:27Seeds that have been buried for years
31:41may now be exposed to light
31:43and come to life.
31:44and come to life.
32:03This is coyote tobacco.
32:05In just a few weeks, it grows a metre tall
32:22and produces dozens of flowers.
32:24The night air becomes heavy with their fragrance.
32:37Soon, they attract hawk moths,
32:40which sip their nectar and in doing so, pollinate them.
32:46But the moths also lay their eggs on them.
32:49Soon, their caterpillars have hatched
33:08and are munching the leaves.
33:10Their nipples expose the plant's sap to the drying air.
33:21But the tobacco plant has a defense.
33:27The leaves under attack produce nicotine.
33:35This chemical sedates the caterpillars
33:37and slows them down.
33:46And what is more, it makes them give off a particular scent.
33:53One that summons others to come to the plant's aid.
33:59Big-eyed bugs.
34:01Miniature assassins only two millimeters long.
34:04And whip-tailed lizards.
34:08Big or small, they make a meal of the caterpillars.
34:11It's certainly effective.
34:13But there's more to this strategy than meets the eye.
34:17When the leaf of a tobacco plant is attacked by a caterpillar,
34:27all the rest of the leaves prepare to defend themselves.
34:30But how does this leaf know that that leaf there is under attack?
34:44Well, scientists here in the United States have specially genetically modified these tobacco plants,
34:47so that under special lighting conditions, this microscope can show us exactly what is going on.
35:04I'm going to attack one of the leaves of this plant with these tweezers,
35:12which to the plant will seem as if it's being nibbled by a caterpillar.
35:17Signals are being transmitted along the veins that link the leaf to the rest of the plant.
35:37It's rather like a very simple nervous system.
35:40From that initial injury, the whole of this little plant is aware that something has happened.
35:57This signal warns each leaf of the danger,
36:01so that it is ready to produce nicotine the moment it's attacked.
36:06With this defense at the ready, the tobacco plant can continue to grow until eventually it produces seeds.
36:16It's particularly important in deserts for seeds to be distributed as widely as possible,
36:37so that some will have a chance of reaching moisture.
36:40And deserts have an excellent agent to help them do that.
36:49The wind.
36:53Many seeds have adaptations to help them exploit it.
36:58They have shells to protect the seeds within from abrasion.
37:03Or wings to help them catch the air.
37:06As the temperature rises throughout the day, desert winds increase in strength.
37:36Here in Arizona, the land is regularly swept by what is known as a haboob.
37:47It's a giant sandstorm, but also, in effect, a seed storm.
37:52Countless millions of them are swept up into the air.
38:05Some seeds can travel thousands of miles on the wind.
38:10So that plants may eventually reach even the most isolated desert.
38:23Some have landed on an island in the middle of the world's largest salt flat in Bolivia.
38:38In the Galapagos, they sprout on fields of recently erupted lava.
38:50They've even reached one of the most inhospitable of all sites.
38:56The tiny island of San Pedro Matilla, a scorched lonely rock off the coast of Mexico.
39:10This is the home of the giant Cardone, a species of huge cactus that can weigh up to 12 tons.
39:23They're able to thrive here because of an extraordinary partnership.
39:39With brown and blue-footed boobies.
39:43The Cardones here can become so broad that they provide cooling shade for nesting birds.
39:55As the booby chicks get older, they repay the Cardones.
40:12With their droppings.
40:18With their droppings.
40:21Guano.
40:23The digested remains of vast shells of fish.
40:28This guano is of such strength and quantity that most plants would be poisoned by it.
40:34These Cardones, however, have evolved the ability to tolerate the toxins in the guano and digest the nutrients.
40:50As a result, the cacti now grow in a dense forest over a million strong.
40:56But such relationships are very finely balanced and can only too easily tip into catastrophe.
41:12As is now happening in northern Zimbabwe.
41:15For six months of the year, the savannah here is kept lush and green by daily rains.
41:34But when the rainy season is over, it becomes as dry as any desert.
41:39So to survive here, trees must be able to tolerate both conditions.
41:53And these giants are adapted to do just that.
41:57They are baobabs.
41:59This one might be over a thousand years old.
42:11It survives here in part thanks to its ability to store thousands of litres of water within the spongy wood of its trunk.
42:19But its battered surface is evidence of a very finely balanced relationship.
42:32These huge trees are a focus for animals of all kinds.
42:42And they're particularly important for elephants.
42:49In the wet season, they eat the baobabs' fruit and disperse the seeds in their dung.
43:02Now, as the dry season begins, they migrate to distant watering holes.
43:13The baobabs have damp inner wood.
43:15And the elephants use it to quench their thirst on the journey.
43:20on the journey.
43:41This relationship can only work because baobabs have a remarkable ability to heal themselves.
43:48Between each damaging attack, they expand their spongy wood and grow new skin.
44:13new skin.
44:18And they've done this time and time again over centuries.
44:27Today, however, it's harder for the baobabs to recover,
44:31as dry seasons become longer and drier due to climate change.
44:35Not only that, but the elephants are forced to take ever more wood from the trees in order to survive.
44:44In some parts of Africa, many of the largest and oldest baobabs have fallen in the last decade.
44:57The loss of a vital species like the baobab strikes a blow at all life in the desert.
45:16In these hostile lands, few living organisms can survive without help from others.
45:28You can find an extraordinary illustration of this in Arizona's saguaro country.
45:39If you wander off the beaten track here, you may be lucky enough to find one of these.
45:52It might look like an old boot, but in fact, it's part of a saguaro cactus.
45:58Almost every saguaro has one. There's one up there.
46:09It has been produced, indirectly, by woodpeckers,
46:13which regularly dig homes for themselves in the bloated trunks of the saguaros.
46:18In the next six months, the cactus heals the wound,
46:37and so creates a safe, cool, and watertight nest hole.
46:41Its tough lining will persist for years even after the cactus itself has died and rotted away.
46:54A single saguaro may hold several of these extraordinary homes.
47:02So over its lifetime, it may provide accommodation for some 3,000 chicks of several different species.
47:09But in the long term, the saguaro benefits as their lodgers repay the cactus
47:23by pollinating its flowers and dispersing its seeds.
47:29It's relationships like these that enable life to flourish in some of the world's harshest landscapes.
47:44Over millions of years, plants have become superbly adapted to hostile desert conditions.
48:04But it's a very finely balanced existence, and one that makes them uniquely vulnerable.
48:15However, our growing understanding of the complex ways by which desert animals and plants rely on one another
48:22is now helping us to understand how best we can protect them.
48:26Ninety years ago, a photograph was taken from this very spot that shows a population of saguaro cactus
48:39that was very different from what it is today.
48:41In the last 50 years, the population of saguaros here has greatly diminished, not because of a direct assault on the cactus,
48:54but because many of the shade-giving nurse trees were harvested for firewood,
48:59leaving young saguaro to die in the sun.
49:01Now that this relationship is understood and the nurse trees are protected,
49:12there are already signs that the saguaro are recovering.
49:20Wherever there's a desert, plants have evolved to meet its challenge.
49:24But everywhere, they need our help.
49:31As we understand more about them and their intimate and complex relationships,
49:37we will be better able to protect them and all life
49:42in these beautiful but increasingly fragile worlds.
49:54The most remote shoot for the desert's team is to the island of San Pedro Martir in the Sea of Cortez, Mexico.
50:13They are to film the giant cacti that have found a unique way to thrive here.
50:18It takes 48 hours to travel the 260 miles over unpleasantly choppy seas.
50:35It's not made some of us feel very well. I think one of us is quite seasick.
50:39There's nothing but big blue out there and the island is somewhere in that direction.
50:47Can't see it yet.
50:50As they draw close to the island, there's a spectacular reminder of how rich life in the sea is here.
50:58Oh, look in front of us! Look at that for a pot!
51:02Oh, they're everywhere!
51:10Show us the way!
51:18Meeting them here is desert scientist Ben Wilder.
51:23It's through his research that the team first heard about the island's peculiar residents.
51:29I'll never forget the first time I came to actually exactly where we're standing right now.
51:34It was April of 2006 and saw this view and it both settled in my heart and captivated my mind.
51:45And so that started a process of trying to understand, you know, what can produce this?
51:53The secret is in the relationship between the cactus and a type of seabird called a booby.
52:05All the boobies that we need to film are right up there at the top of the island, so it's going to be a bit of a scramble.
52:11The crew soon discover how harsh the conditions are here.
52:18Pretty hot. It's pretty hot. It's a great view.
52:21There's very few places on earth where you're going to see this many cactus. I mean, it's absolutely amazing.
52:36I would say this is the only place you're going to see this.
52:39Well, there you go then.
52:40Ben's research is uncovering the ingenious ways the cacti have adapted to the conditions here.
52:49The waters just offshore here are some of the most productive marine waters in the world.
52:55And so it's kind of an ideal habitat for seabirds to roost.
52:58But when they do so, they deposit tons of guano.
53:02And so those nutrients, really high in nitrogen and phosphorus, actually are toxic to most plant species.
53:08The Cardones thrive because they're uniquely able to process the guano and extract what they need to fuel their growth.
53:19One of the first shots the crew need to get is of the boobies nesting under the cacti.
53:26The lack of predators means the birds aren't afraid of people.
53:31It should make filming them up close a bit easier.
53:35That's the theory.
53:36So we better position this camera here to try and get a good perspective on the chick, on the nest.
53:42It's taken quite a liking to our camera.
53:45Let's hope it doesn't break here.
53:53Bullseye. It's pooed right on the front of the lens.
53:57It's kind of a shot we need, but unfortunately, my camera wasn't rolling at the time it did it,
54:01so now I've just got a dirty lens.
54:06After a thorough lens clean, Ollie eventually gets the shots to reveal the extraordinary relationship between bird and plant.
54:14But it's not just the bird guano that influence how the Cardones grow.
54:23They're way shorter. They're dwarfed here.
54:27Throughout the rest of their range they usually get in upwards of 50, 60 feet.
54:31But here, on average, they're 20, 24 feet in height.
54:36They stop growing up and they grow out.
54:42Ben's research suggests that they grow wide here as an adaptation to the violent winds.
54:48Too tall and they'd blow over.
54:49A gusting wind isn't helping the drone crew either, Ollie.
54:55We really need it to calm down a bit, otherwise it's gonna be impossible.
55:01Be quick.
55:03Bonnie, keep an eye on it.
55:05It's not safe.
55:08Bring it out.
55:19On the Sonoran mainland, where the Cardone is also found, you have on average between 50 to 150 plants per hectare.
55:31Here, on this island, you have over 2,500 plants per hectare.
55:36A lull in the wind and the team get a chance to reveal the remarkable density of the cacti.
55:43Almost 20 times greater than anywhere else.
55:46It appears that here they're doing very well.
55:50But even this island isn't isolated from the effects of a changing planet.
55:57Every cactus you see there, its body is filled with nutrients from the sea.
56:03Given that we know that the Cardones are linked to the ocean,
56:08what happens in the ocean affects what happens to the Cardone.
56:12So a concern we have right now is that there's a lot of overfishing.
56:16And we know there are less seabirds here than there were 20 years ago.
56:21And we have reason to believe that that will ripple and affect the nutrients that fuel the Cardones as well.
56:30This finely balanced relationship is at risk.
56:34And knowing that makes leaving the island particularly thought-provoking for the crew.
56:38The Cardones look beautiful. I've never seen so many cactus in my life. It's absolutely amazing.
56:47I'm just hoping that when we leave this place, it stays as it is and things don't affect it. They're negative.
56:52It's an absolutely wonderful thing. And yeah, I don't want to go. I'm a mistake.
56:58This remote cactus forest is a reminder of the adaptability of plants.
57:04that enables them to establish green worlds almost anywhere on Earth.
57:15Next time on the Green Planet, our extraordinary relationship with plants.
57:21From those we eat, to those we help, plants are our greatest allies.
57:35The Open University has produced a poster that explores the vital role that plants have for our planet.
57:47To order your free copy, call 0300 303 4200
57:52or go to bbc.co.uk forward slash green planet
57:58and follow the links to The Open University.
58:05Be taken on a journey to calm with beautiful music and Sir David's wonderful voice.
58:10The Green Planet, Mindful Mix. Listen now on sounds.
58:14An emotional odyssey, The Caribbean with Andy and Makita
58:16continues with Song Swimming as Surprises on BBC Two at 9.
58:21On BBC Four now, a celebration of classic MGM music.