Hello, everyone. I’m Rock.
Today, let’s talk about a kind of plant with very special meaning.
It’s a sweet potato.
Also known as sweet potato, sweet potato or potato
Different places have different names.
But they must know each other, right?
So sweet potato looks like a very common kind of food.
Why is it special?
Because its genome is a little unusual.
It is said that it is known in the world
The first genetically modified crop
Moreover, it is genetically modified.
It’s not the work of human genetic engineering.
But from an unknown event.
After genetic analysis
It may have to be at least 8,000 years ago.
It’s ridiculous.
That’s why it’s a very special plant.
We’ll talk about that in detail later.
The English name of sweet potato is sweet potato.
Sweet potato
And look at how many Chinese names it has.
Like sweet potatoes, sweet potatoes and so on
Also with potatoes, potatoes, Dutch potatoes
The names of these potatoes are a bit like
So it gives people an illusion.
Is it close to potatoes?
Actually, it’s not.
First of all, although both of them were dug out of the earth,
But a potato is a tuber.
And sweet potato is a kind of root tuber.
They are different in nature.
Besides, the biological classification of potatoes has been mentioned before.
It belongs to the same family as eggplant and tomato
Solanum from → Solanaceae
Then, although sweet potatoes are also eggplant order,
But it belongs to the sweet potato genus of Convolvulaceae.
It’s not the same subject, so it’s not a very close relationship.
Although the genus sweet potato is called “sweet potato”
But in fact, most of the species in the genus
It’s not a “potato”.
But what?
It’s a bit of an accident. Morning glory.
That is, trumpet flowers, which are very common in the wild.
It is said that there are about 600 species of sweet potato.
Most of them are similar to morning glory.
This may be unexpected to a lot of people, right?
And then it’s in this pile of “wild flowers.”
It is surprising that there is a kind of sweet potato with thick roots.
And become a wonderful work of delicious food.
That’s quite different.
So in the end, where did morning glory become a sweet potato?
The place of origin of this sweet potato is the same as the potato.
Also in America.
So who is the wild ancestor of sweet potato?
Let’s move on.
The scientific name of sweet potato is batata.
The word comes from the aborigines of the Caribbean.
It’s called the Taino.
The Taino people call their sweet potato variety batata
And then an audience may have noticed.
Say the word batata
Why does it sound like potato?
As a matter of fact, there is such an origin.
Because when Columbus first discovered the New World,
There are too many things I haven’t seen before.
Spaniards are confused, aren’t they?
So when you see potatoes,
The name batata of sweet potato is also quoted.
Name the potato patata.
Later, English became potato.
Here’s what happened.
So it is certain that sweet potato originated in America.
But who are their ancestors?
This problem has plagued the scientific community for a long time.
It is said that the genome of modern sweet potato is hexaploid.
Scientists infer that it is a cross between two ancestors.
One is diploid.
One is tetraploid.
One of the diploid ancestors is a kind of
Morning glory of Ipomoea trifida
Distributed around the Caribbean
The roots of these plants are very fine
It is said that it is as thick as a pencil
Has no edible value at all.
Its relationship with sweet potato has actually been confirmed a long time ago.
But what’s the problem?
That is, the tetraploid ancestors of sweet potato have never been found.
The scientific community has been looking for it for almost 100 years.
And finally, the year before last, ah.
That’s 2022.
A team at the University of Oxford published a study
Said he found it in Ecuador.
It’s a morning glory growing in weeds.
The flowers are white and purple.
The root is also very thin and can’t be eaten like that.
So according to genetic analysis,
It may be what scientists have been looking for.
Tetraploid ancestors of sweet potato
The researchers named it
Equatorial Petunia (Ipomoea aequatoriensis)
It is said that it crossed with “Big Star Petunia”.
It was only later that hexaploid sweet potato was produced.
They are the wild ancestors of sweet potato.
All right, the ancestors of the sweet potato found it.
But it’s still weird.
You can tell by comparing potatoes.
It is said that the tubers of potatoes are so big.
Although it is also cultivated by human beings.
But the ancestors of potatoes had tubers of their own, right?
It’s just that it’s small and toxic.
There is always some.
But the sweet potato side is very weird.
Because the roots of the two kinds of morning glory of its ancestors are very thin.
No root tuber.
How come the root tuber suddenly thickens after the cross?
There’s a question.
So, about this,
The answer lies in the genome of sweet potato.
Said there was a study in 2015.
The scientists studied 291 sweet potato varieties.
Genetic analysis was carried out.
And these varieties of South America and North America
Both in Asia and Africa.
Basically represent all the mainstream sweet potato varieties in the world.
And then the results of genetic analysis
There’s a discovery that’s very unusual.
Say that all 291 kinds of sweet potatoes
All have a DNA sequence that does not belong to the sweet potato.
Even this DNA doesn’t come from plants.
Where does it come from?
From a kind of bacteria.
It’s called Agrobacterium.
This kind of Agrobacterium tumefaciens is all too familiar to scientists.
Because it’s a tool for improving plants in the laboratory.
Specifically, what can it do?
It can be transferred through “horizontal gene transfer”.
Inject a piece of DNA into plant cells.
Just like some viruses.
Agrobacterium tumefaciens is very good at this
Like in the lab.
You can mix Agrobacterium tumefaciens with some kind of plant cell.
Let Agrobacterium tumefaciens transfer a small piece of DNA into plant cells.
Then induce these plant cells to replicate and grow.
You can get a genetically modified plant.
In a nutshell, that’s it.
What is the effect of DNA transferred by Agrobacterium tumefaciens?
The effect is right at the root.
It is said that it will cause the roots of plants to swell and grow nodules.
So scientists think that the root of sweet potato
It’s probably caused by transgenic Agrobacterium tumefaciens.
It’s just that this wave of operation is not in the laboratory.
It happens naturally in the wild.
And it’s presumed to be 8,000 years ago.
Probably because of the Native Americans.
After being “genetically modified”
Morning glory with a root.
It was only then that they began to cultivate them for food.
Finally, sweet potato was cultivated.
In other words, sweet potato is equivalent to a kind of
Natural genetically modified crops
It’s so magical.
In addition to explaining the origin of sweet potato, this discovery
There may be an additional impact.
Is the safety of genetically modified food.
Because for now, ah,
Although there is no evidence yet.
It is said that genetically modified food is better than traditional food
What’s the extra harm?
But there is a general public concern.
That is, after all, the time for transgenic technology is relatively short.
Who knows for more than a decade?
What happens in a few decades, right?
There are some arguments that take time to verify.
So it just so happens that sweet potato is genetically modified.
I’ve been eating for thousands of years.
It can provide some reference.
So what do you think of genetically modified genes?
You are also welcome to leave a message for discussion.
Sweet potato, as the offspring of morning glory, will certainly blossom.
And it is also a trumpet flower.
But many friends may not have seen it.
Because they need to meet some conditions to bloom.
Generally speaking, the temperature is between 20 and 30 ℃.
At the same time, the daily sunshine time is less than 11 hours.
It’s easy to bloom.
So basically, only the tropics can meet this.
Like the one in Central and South America where they came from.
It can bloom normally.
In the temperate zone, the sunshine in summer is too long.
So sweet potatoes usually don’t blossom.
So since sweet potatoes can blossom
Of course, it will bear fruit, and there will be seeds.
The fruit of sweet potato is green
The shape of a small ball
Finally, some small black seeds are produced.
But it’s the same as the “potato” I said before.
Sweet potato can not be self-pollinated.
Can only produce “hybrid” offspring.
So human breeding for thousands of years
A lot of sweet potato varieties have been produced.
It is said that there are about 7000 known species.
More than potatoes.
And generally speaking, sweet potatoes are not planted with seeds.
Because it can’t guarantee genetic stability.
You can only use “clone” like potatoes.
But potatoes are planted with “seed potatoes”.
That is, cut the tuber and plant it.
Then the sweet potato is different.
It is planted with sweet potato vines.
It’s about 20 centimeters long.
With a few leaves on it.
Bury it obliquely into the earth.
This is how the leaves are exposed.
Sweet potato is also considered to be
As the Columbus Exchange went to the world
But there’s one place that’s special.
The South Pacific Islands.
Judging from the archaeological evidence available,
It’s possible that Polynesians in the South Pacific
Sailed to South America hundreds of years before Columbus
Take the sweet potato back and plant it.
And it has become the main food crop on many islands.
There seems to be evidence of this in their language.
For example, the Maori sweet potato is also called kumara.
It just so happens that the indigenous language along the coast of Peru is also called cumara.
It obviously has something to do with it, right?
That’s why the South Island people can give birth to so many people.
There may also be the credit of sweet potato.
Like the famous Easter Island.
The Rapa Nui on the island
The main food crop is sweet potato.
In other words, if they don’t have sweet potatoes to fill their stomachs,
Maybe we won’t have the time to build stone statues.
It’s no exaggeration at all.
It’s all caused by sweet potatoes.
So, in addition to the South Pacific islands,
The rest of the world
It was all spread by Europeans after Columbus.
It is said that the Europeans brought sweet potatoes back to Europe first.
The result was very popular.
After all, it’s really sweet and delicious, isn’t it?
So it soon became the food of the upper class.
Rich people want to taste this exotic flavor.
Potatoes were originally called “devil plants”.
It’s not popular at all. that’s so different.
Later, Europeans entered the era of great navigation.
Spread sweet potatoes and other crops all over the world.
But now the place where sweet potatoes are used as the main food rations
Actually, it’s not a lot.
Now, in terms of world sweet potato production,
It can produce about 100 million tons a year.
Among them, China accounts for about 55%.
The rest are basically some African countries.
Such as Malawi and Tanzania
A poor area like Angola
That is to say, most parts of the world
Sweet potato is more of a non-staple food.
Will not be a staple food.
So it’s a little weird.
Because if it depends on the planting efficiency,
Of all the crops
Sweet potato is actually very top-notch.
For example, the Food and Agriculture Organization of the United Nations has arranged
It is said that per hectare of farmland
In terms of the amount of heat produced every day.
Sweet potato can produce 70,000 kilocalories per day.
Rank first among all crops
Good seed and high yield
In other words, it is actually the most cost-effective to use it to provide energy.
So why on earth are sweet potatoes?
Failed to become the staple food of modern society?
This is the topic of how to eat sweet potatoes.
Well, if you eat too many sweet potatoes, there is one thing that everyone knows.
Just love to fart.
What’s the reason?
Some people say that there is an enzyme in sweet potato.
This enzyme causes the gastrointestinal tract to produce large amounts of carbon dioxide.
Then some people say that it is because sweet potatoes contain a lot of cellulose.
The fiber ferments in the intestine to produce gas.
Promote gastrointestinal peristalsis, so it’s easy to fart.
These are two common expressions.
And then there is also some research.
It is speculated that another substance produced the gas.
It’s mannitol.
Mannitol is a sugar alcohol that is difficult to digest.
The content of sweet potato is high.
If you eat too much, it is easy to appear.
Symptoms such as flatulence and heartburn
Anyway, sweet potatoes are delicious.
But it is too inappropriate to eat as a staple food.
In the poor period, sweet potatoes used to be the staple food.
There’s nothing I can do about it.
Whenever there is rice or wheat at home
No one eats sweet potatoes all at once, right?
It’s really hard to eat too much.
There are obviously two categories in terms of the species of sweet potatoes.
Some sweet potatoes are orange-yellow in meat.
It’s more sticky when it’s cooked.
So these varieties are because they contain a large number of
That’s why β-carotene is orange-yellow.
It tastes sweeter, too.
Like our favorite baked sweet potato.
Steamed sweet potato, fried sweet potato and so on.
Those are all better in this way
Everyone loves sweet food
But if you eat it as a staple food
If it is too sweet, it will not suit the taste
After all, people still have a need for salt when eating.
You have to eat salty food
So sweet potatoes that used to be the staple food
Including sweet potatoes now grown in poor areas of Africa
They usually go in the other direction
The color is white
Variety with drier and more flyer meat
These are not sweet
It is more suitable for serving as a staple food and eating salty dishes
here’s the thing
So if you eat it as a non-staple food
There are too many ways to eat sweet potatoes
But personally,
Roasted sweet potatoes definitely belong to YYDS
Bake it until golden yellow, shiny and shiny
Think about it, it’s delicious, right?
There is no doubt that the first way to eat
And then in addition to roasting sweet potatoes,
Sweet potatoes can also be made into fried sweet potato balls
Sweet potato soup, sweet potato porridge and the like
These are also common
In addition, especially Shandong cuisine
There are two ways to eat that are particularly recommended
They are silk sweet potatoes and glazed sweet potatoes
These two cut the sweet potatoes into slices and fried them thoroughly first
Then wrap it in stir-fried syrup
But what is the difference?
It is that the shredded sweet potatoes are served hot
When you eat, you will pull out silk
You need to dip it in cold water before eating it
Glazed sweet potatoes must be dried one by one after they are out of the pot
Wait until the sugar has solidified before loading
They don’t stick to each other and make it easier to eat
If you have the opportunity, I recommend everyone to try it
In addition to the roots of sweet potatoes,
In fact, sweet potato vines can also be eaten
Of course, ordinary melon vines are basically fed to livestock
People don’t usually eat
But there are also some specially cultivated sweet potato vines
The tender leaves at the end can be eaten as vegetables
The name of the dish is usually called sweet potato leaves
You can eat it stir-fried or boiled
It’s like eating water spinach
Maybe many viewers have eaten it
And what should I add here?
The common water spinach is also called water spinach
It’s also sweet potato
They are very close relatives to sweet potatoes and morning glory
Many people may not know this
As morning glory people,
It is said that some sweet potato varieties have become ornamental plants
Generally, the main focus is on appreciating leaves
Occasionally, I watch morning glory
Although these ornamental sweet potatoes also have root roots
But they are usually small and bitter
It’s not delicious at all
It has no edible value at all and can only be viewed as a viewing
In addition, finally, there is a kind of sweet potato that everyone is familiar with
It’s the purple-fleshy kind
Maybe some viewers will think it’s purple potatoes
is not
It can only be called purple sweet potato
It’s a variety of sweet potatoes
As for real purple potatoes, they are another species
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