Growing Fruit in the Desert


Prickly pear cactus with fruit.
Mike Kelley, via Flickr

Adam Navis and Liz Waid look at an amazing plant - the cactus!  It needs far less water than most plants.

Transcript


Voice 1

Welcome to Spotlight. I’m Liz Waid.

Voice 2

And I’m Adam Navis. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.

Voice 1

In the last 15 years, farmers in Israel were experiencing a serious problem. They were finding it more and more difficult to grow their fruit crops. The earth was just too dry for their fruit trees. And it was difficult for them to find extra supplies of water. Yosef Mizrahi is a farming expert. He told the BBC,

Voice 3

“Farmers in the desert had lost all of their money. They were removing their fruit trees. What we did in the past is not working any more. We had an insane idea: why not take desert plants, and make them into crops?”

Voice 2

The farmers needed to find a new way to grow crops in dry areas. So they turned to a desert plant, the cactus, for help. Cacti need far less water than most normal plants. They have physical and structural qualities that set them apart from all other plants.

Voice 1

The farmers began using a special cactus that can produce fruit. It is called the nopal. It is also called the prickly pear. They added special fertilizers, or plant growth chemicals, to the nopal. The nopal began producing fruit for 11 months out of the year.

Voice 2

So how are cactus plants able to grow so well in dry areas? How do they stay alive without a dependable water supply? Today’s Spotlight is on the cactus.

Voice 1

Most people recognize the cactus plant by its sharp spines, or points. But there are other things that make the cactus plant different than other plants.

Voice 2

Scientists think that long ago the cactus looked much like any other plant. It had a stem which grew out of the ground. On the stem there were leaves. And, sometimes there were even flowers. But, over the years the seeds of cactus plants started to spread. They moved into more difficult places, including hot, dry deserts.

Voice 1

When cacti started to grow in dry areas they slowly began to change. Like all desert plants, cacti had to survive for long periods of time without water. Soon, the cacti’s stems started to grow thicker. The thick stem could store water.

Voice 2

The stem of a cactus is made up of many special cells. These cells store the water. The walls around each cell are very thin. So, the walls can stretch. When it rains these cells fill up with water. They stretch wide to make sure they are completely full. After a good rain, cacti are made of ninety percent water!

Voice 1

Over time there were other changes to the cactus plant. These changes helped the plant to survive even better in dry places. The stems became thicker and thicker. Soon, the chemical chlorophyll appeared in the stem.

Voice 2

Chlorophyll is very important to both plants and trees. People can usually find chlorophyll in a plant’s leaves. Chlorophyll gives leaves their green colour. But chlorophyll has another important purpose. It creates the plant’s food. The plant’s energy to stay alive comes from chlorophyll.

Voice 1

Once the chlorophyll moved to the cactus stem, the cactus no longer needed leaves. The leaves were actually a problem! The leaves were a barrier to the sun’s light. The chlorophyll in the stem could not receive enough sunlight through the leaves. Soon, cactus leaves became smaller and smaller. And today, there are usually no leaves growing from the cactus stem. The stem now produces food.

Voice 2

The leaves may have disappeared for another reason too. All plants lose water. Water evaporates into the air from every part of a plant’s surface. So, a good way for a plant to survive in dry areas is to shrink its surface area. Then it loses less water. The cactus has a much better chance of surviving without the surface area of leaves.

Voice 1

For these reasons, the cactus plant also makes food in a different way than all other plants. Most plants use energy from the sun, carbon dioxide from the air, and water from the earth. Special holes, called pores, cover the plant. During the day, the plant opens these pores to let in the sun and carbon dioxide. Immediately, the chlorophyll uses the sun’s energy and the carbon dioxide to make food. But the heat of the desert sun presents danger to the cactus plant. The heat could easily evaporate the plant’s water.

Voice 2

So, the cactus performs a special trick. It does not open its pores during the day. Instead, the cactus opens up its pores at night. The temperature is cooler at night. So, the cactus loses less water. And, instead of using the carbon dioxide immediately, the cactus changes this gas into a liquid acid chemical. It stores the acid until morning. When the sun begins to rise, the cactus closes its pores again.

Voice 1

The next day the cactus uses the acid to create food. The chlorophyll gains energy from the sun through closed pores. This energy helps the chlorophyll use the acid to create food. As the day goes on, the cactus uses all of its stored acid. By the end of the day the cactus has lost most of its stored acid. So, it must repeat this process every night.

Voice 2

There are some animals that feed on desert cacti. But if an animal eats a cactus in the early morning, it will get a pain in its stomach! That is because they are eating the cactus when it is filled with acid!

Voice 1

Some desert plants send down long roots to get water from deep inside the ground. But cacti have a different root system. Their roots do not go deep down into the ground. Instead, cacti roots spread in all directions. The roots gather water from a very large area. Even a small cactus plant may send its roots a distance of nine to twelve metres from the area where it grows. There are scientists who study the roots of the desert cacti. They say something surprising. If we looked at the ground underneath a desert, it would look like a thick forest of roots!

Voice 2

Cacti are native to the Americas. Europeans first saw cactus plants when they discovered the New World. These travellers brought cacti home to Europe with them. Since then, people have planted cacti in many parts of the world. Now, you can find cacti growing in dry areas almost everywhere. They are a supply of food, water and beauty in many places.

Voice 1

Do cacti grow where you live? Do you eat any foods from cacti? Visit our website at www.radioenglish.net to tell us about your experiences.

Voice 2

The writer of this program was Rebekah Schipper. The producer was Michio Ozaki. The voices you heard were from the United States. All quotes were adapted for this program and voiced by Spotlight. You can listen to this program again, and read it, on the internet at www.radioenglish.net. This program is called, ‘Growing Fruit in the Desert’.

Voice 1

We hope you can join us again for the next Spotlight program. Goodbye

Question:

Do you live near cacti plants? Do you eat any food from these plants?

Comments


Avatar Spotlight
nature187_vn
said on October 27, 2011

I really like image of the cactus.In difficult enviroment of nature,hot weather,dry air,low humidity,it still live and grow.I wonder if humans like the cactus,we can overcome all difficult in the life…
Thank you program’s story for sharing much meaning topic and useful for everyone!

Avatar Spotlight
José María de Córdoba
said on February 05, 2012

Hello all
I listen one story of Spotlight everyday, it’s really wonderful and I hope learn any of English. Thanks for you dedications.

Avatar Spotlight
NightlyOwl
said on May 16, 2012

Unfortunately, in Ukraine cacti do not grow simply as a plants on the ground. But we have cactus like exotic flowers in our pots on windowsills. Often, there is recommended to put cactus near the computer, because they take negative radiation. But I even do not imagine what kind of fruit can be in a cacti?

Avatar Spotlight
paulo86nirisco
said on November 28, 2012

Cacti grow very much here in Brazil , but I never ate one

Luis Piedra's avatar
Luis Piedra
said on November 28, 2012

Good Program.
Thanks Spotlight

Avatar Spotlight
Yazdan
said on November 28, 2012

Thanks Spotlight Radio group.
I listen and repeat your programs for imporve my english pronunciation.

I found on defference between voice and text at the first paragraph .

text : And it was hard for them to find extra supplies of water.
voice:And it was difficult for them to find extra supplies of water.

Thanks for your good programs .

Robin Basselin's avatar
Robin Basselin
said on November 29, 2012

Yazdan-

Thank you for your comment.  And great job noticing the error.  We have made the change to the program text. 

Robin

Avatar Spotlight
MinhDuc
said on December 12, 2012

It is very interesting topic. How intelligent the Cacti are? I do not think we are (people) are more intelligent than them actually!

Mupmip218's avatar
Mupmip218
said on October 22, 2015

In Vietnam, the cactus is everywhere. But I’ve never seen someone eat cactus!

Avatar Spotlight
DUNG_GEO
said on December 23, 2015

I am one of Vietnamese people. People who live in Ninh Thuan, Binh Thuan province usually see cactus. The cacti does not grow with goal for produce fruit. They naturally grow in free land, where has condition less water. When I join working survey geology at Ninh Thuan province, I was hungry, thirsty. I see very much fruit of cactus. And I had eaten them. They had taste sweet. Thank you Spotlight made me again live with some celebration.

Kaleb Kolaibi's avatar
Kaleb Kolaibi
said on June 28, 2016

The cacti plants exsisting a lot of in my country (Yemen). When I was child I was lived at Village I had eating it so much. Then, when I moved to capital city I still eating it but from market.
New, in Ethiopia as a refugee, I dont eat it since 1,6 year.
Actully that cacti is delicious and I like it.
God bless you

Severino Ramos da Silva's avatar
Severino Ramos da Silva
said on July 01, 2016

From: .(JavaScript must be enabled to view this email address) (Severino Ramos)
To: spotlight programme
Subject: answer to the question above
Date : Friday 01,  July 2016
São Paulo SP Brazil

Dear Liz Waid, Rebekah Schipper, Adam Navis, and Michio Ozaki:

First of all, I want to thank you to bring us readers and learners of English more one great article. Thanks!
No, I do not. Here in Brazil there are many cacti plants in the north-east, where the ground is very dry and there rains only once a year.
No, I do not. And I have never eaten them because I have never seen one of them. However, I would like to see one of that plants and to try one of them.
Cacti plants are beautiful plants in which I just have seen them by television.

Yours regards,
Sevrino Ramos
Brazil