# data[].attributes.attachment_link.title
DK Find Out! | Fun Facts for Kids on Animals, Earth, History and more!

# data[].attributes.attachment_link.description
Visit DK Find Out! to learn about dinosaurs, space, animals, nature & more. Fun learning activities for kids with videos, quizzes & galleries at DKFindOut.com

# data[].attributes.attachment_link.readable_text
When you think of the , what comes to mind? You might think of a dry, landscape. Long stretches of sand may also come to mind. Of course, there's probably one other image that's likely to pop into your brain. What are we talking about? The , of course!

Any movie or cartoon ever set in the always features the . Often, it's pictured as a , , plant that manages to survive the heat without . However, there are actually over 2,000 different types of cacti (that's what you call more than one ) in the world.

Some cacti are , , and like the ones you may have seen in movies or cartoons. Those are often a specific type of called the . Many cacti, though, are much smaller and come in a variety of colors and shapes.

Cacti are native to the Americas and can be found from the southern tip of South America to western Canada in North America. They usually live in areas that are relatively dry. Many cacti in areas that are extremely dry, such as the Atacama - one of the driest places on Earth.

Like all living things, cacti need to survive. Given the areas where they live, though, is often . To compensate , cacti have developed special abilities that allow them to conserve the they do receive and make it last a long time.

For example, the of cacti are actually highly- leaves. protect cacti from animals that eat plants and also help to reduce loss by restricting air flow near the .

Most cacti have , but shallow root systems that allow them to soak up any rainfall that may come their way. Specialized stems allow cacti to store for a long time, since rainfall is often in the deserts that cacti call home.

For example, a fully-grown can soak up and store up to 200 gallons of during a good ! Many travelers have learned that, in an emergency, a can be opened to find life-saving fluids.

# data[].attributes.attachment_link.description
When you think of the , what comes to mind? You might think of a dry, landscape. Long stretches of sand may also come to mind. Of course, there's probably one other image that's likely to pop into your brain. What are we talking about? The , of course!

# data[].attributes.attachment_link.title
Fun Cactus Facts for Kids - Interesting Information about Cacti

# data[].attributes.attachment_link.description
Certain kinds of cactus have fruit that are a popular source of food. The dragon fruit (pitahaya) is now widely grown in Asia. The prickly pear or Indian fig are varieties of cacti whereby both the fruit (called tuna in Spanish) and the pads (called nopal in Spanish) can be eaten.

# data[].attributes.attachment_link.readable_text
Can you imagine if plants were like human beings? Envision a bush. One day, a yellow blooms. A few days later, a pink blooms. A couple of weeks later, several red roses together.

Rather than doing their own thing and seeking their own time in the spotlight, however, real bushes all one color with all the flowers appearing at about the same time. It's a glorious sight, and we humans are delighted when we see it.

Those bushes don't at the same time as the lilies and the daffodils, though. Beginning in springtime each year, flowers begin to , with different plants blooming at different times month after month. But exactly how do plants know when to ?

It's a mystery that has puzzled scientists for centuries. As far back as the 1930s, scientists knew that plants somehow sensed the length of days to know when springtime was approaching. Russian scientists suspected that a mysterious substance (a mystery they called "florigen") was sent through the leaves to the tips of shoots to stimulate buds to form.

Today, scientists have conducted advanced studies that they believe might finally explain how plants know when to . For example, scientists now know that plants have an internal circadian clock that helps them know when is increasing and days are getting longer. They believe this internal clock works because of proteins that work as photoreceptors activated by .

Different plants thrive at different times of the year, since they each have individualized needs for , precipitation, and other important factors. This is why not all plants on the first day of spring. Instead, they at the times when they will have the best chance to survive and thrive.

When those photoreceptor proteins tell the that it's time to , the sets in motion a that will result in flowers blooming. Specifically, the plants begin to produce a called Flowering Locus T in their leaves. The then travels to the tips of shoots, where it undergoes changes that spur cells to begin to form flowers. Scientists now believe that Flowering Locus T is the elusive "florigen" Russian scientists speculated about almost 100 years ago.

Why would scientists care so much about how plants know when to ? It's more than just intellectual curiosity. Some scientists believe that understanding these mechanisms will allow them to regulate the timing of flowering of plants grown as crops, such as , wheat, and barley.

For example, usually flowers late in the year. If scientists could manipulate the flowering to create an early-flowering variety of , it could be possible in some areas to produce more than one per year. Other experts speculate that such manipulations could also lead to higher yields of plants grown for biofuels.

# data[].attributes.attachment_link.description
Can you imagine if plants were like human beings? Envision a bush. One day, a yellow blooms. A few days later, a pink blooms. A couple of weeks later, several red roses together. Rather than doing their own thing and seeking their own time in the spotlight, however, real bushes all one color with all the flowers appearing at about the same time.

# data[].attributes.attachment_link.readable_text
Cacti have can be found in rain forests and as far north as Canada. But it is their ability to thrive in the desert, where rain falls infrequently and unpredictably, that is their most remarkable trait.

How do they do it?

By working nights, using alternative methods to generate energy and keeping some prickly tricks up their arms.

"The cacti evolved a whole suite of adaptations to survive living in the desert," said plant evolutionary biologist Erika Edwards.

Standing Tall

They grow only about an inch in their first eight years, typically under a tree for protection. Branches do not sprout until they're at least a half-century old. After 125 years, a saguaro can be 50 feet tall and weigh 6 tons. A few live beyond 200 years.

The pleated ribs of a saguaro expand like an accordion when water is available and contract during dry periods.

In June, a mature saguaro produces a crop of flowers that look like bonnets atop the main stems and arms. Each flower lasts less than 24 hours and must be pollinated. Each flower can produce 2,000 seeds, spread by the defecation of coyotes or birds.

Edwards and Michael Donoghue of Yale University recently determined that the Pereskia genus of leafy shrubs and trees were the first plants to exhibit some of these water-saving traits, about 20 million years ago.

The findings were published in the June issue of the journal American Naturalist.
Risky business
All plants have stomata, little pores in their skin that open and close to collect carbon dioxide. During photosynthesis, plants turn the collected carbon dioxide into food in the form of sugars. The process is troublesome in the desert because water escapes from the pores each time they open.

"If you're trying to conserve water, it's risky business to open the pores and lose water," Edwards told LiveScience.

While most plants open up their stomata during the day, cacti and other nocturnal plants such as the agaves and aloes open their pores at night.

The cooler temperatures, lack of sun, and calmer breezes help cacti retain water.
But in the dark, cacti can't use the sun's energy needed to make sugars out of carbon dioxide, so the hardy plants must store the carbon dioxide for the next day.

Once the sun rises, the plant goes to work making sugars.
Other useful traits
Cacti have also developed succulent tissue, waxy skin, prickly spines, and a specialized root system to take every advantage in their harsh ecosystems.

The stem acts as a reservoir; the plant will expand and contract depending on the amount of water it holds.

The skin's waxy coating helps retain moisture.

The pointy spines protect against thirsty animals looking for a free drink.

In some cacti, spines also collect rainwater and funnel precious drops to the plant's roots.
Surprising tactic
You might think cacti would grow deep roots to search for a constant supply of groundwater. Instead, they often develop extensive, shallow root systems that sit just under the surface of the Earth and can extend several feet away from the plant, ready to absorb as much water as possible.

When it rains, cacti shoot out more roots. During dry periods, roots will shrivel up and break off to conserve the plant's water supply.

"The cactus becomes more hydrated than the soil it's growing in," Edwards said. "It runs the risk of losing water to the soil, so it has to disconnect itself from the soil."

Leafy cacti, such as the Pereskia, and other plants have developed similar water-conserving traits and make their home in the desert, even without the anatomical specializations of the familiar leafless cacti.

"It's good evidence that it's a successful strategy," Edwards said. "The plants do really well in these environments."

Your Amazing Cacti Images: 1, 2, 3, 4, 5, 6

Related Stories

# data[].attributes.attachment_link.title
How Cacti Survive: Surprising Strategies Quench Thirst

# data[].attributes.attachment_link.description
Cacti have can be found in rain forests and as far north as Canada. But it is their ability to thrive in the desert, where rain falls infrequently and unpredictably, that is their most remarkable trait. How do they do it?

# data[].attributes.attachment_link.readable_text
Roses are red,

they smell really sweet.

But thorns they do have,

and that's not so neat.

Sigh. Another attempt at poetry gone . Yet we must press on. We must try and try!

In addition to being the subject of poems, roses are one of the most popular and recognizable flowers in the world today. A dozen of them can make your sweetheart on Valentine's Day!

Roses have been around a long, long time. Native to the United States, the oldest fossilized rose was found on a in Florissant, Colorado. Scientists believe it is 35 million years old!

Roses have been such a popular flower over the years that gardeners have developed several thousand different types of roses! In fact, some experts estimate there are more than 30,000 different of roses around the world today.

Roses are mentioned often in music and literature . They strong emotions, such as love and romance. Depending upon the color of the rose, it can have many specific meanings.

For example, yellow roses represent friendship. White roses and . The most popular, the red rose, conveys feelings of romance and passion.

The delicate petals of roses contain oils that can be used to make various perfumes and fragrances. Have you ever noticed how many perfumes try to the sweet natural smell of a fresh rose?

Unfortunately, almost all roses also come with thorns. Or do they? Although most people use the term "thorn" to describe those sharp protrusions that line most rose stems, botanists would actually call them by another name: "prickles."

In botanical terms, "thorn" describes a sharp, strong protrusion that is embedded into the woody structure of a plant's stem or branches. Thorns usually can't be broken off easily. "Prickles," on the other hand, are smaller outgrowths from a plant's outer layers, known as the epidermis. Since they don't have deep roots within the plant, prickles are much easier to break off.

Unless you're a botanist, you probably don't know about prickles, so we'll call them thorns for purposes of our discussion. The bushes that roses usually grow on can be a prickly (pun totally intended!) danger to unsuspecting hands attempting to grab a precious flower. Some scientists that roses might have thorns to protect them from being eaten by animals attracted by their wonderful smell.

Not all roses have thorns, though. Most do, but there are a very few of completely thornless roses. There are also several of "nearly thornless" roses, which just have fewer thorns spaced farther apart than typical roses. These types of roses are great for planting along walkways or using in gardens tended by younger children.

# data[].attributes.attachment_link.description
Roses are red, they smell really sweet. But thorns they do have, and that's not so neat. Sigh. Another attempt at poetry gone . Yet we must press on. We must try and try! In addition to being the subject of poems, roses are one of the most popular and recognizable flowers in the world today.

# data[].attributes.attachment_link.description
Rose bushes are always a good choice for a garden. If planted correctly, they'll flower the first year. There are two ways to plant them: the barefoot method (roots are exposed) or the container method (roots are not exposed).

# data[].attributes.attachment_link.readable_text
Have you ever stopped to take a look at the world around you and think about how many different types of plants you see? A simple walk through your backyard or a local park will reveal hundreds of different types of plants.

Plants take on many shapes, sizes and colors, yet they are quite similar in how they're put together - for the most part. Whether you're looking at a tree, a flower or a blade of grass, all plants have certain things in common.

Plants conduct photosynthesis , a process through which they convert the sun's energy into food they need to grow and survive. Photosynthesis occurs in chloroplasts, which are tiny organelles located within plant cells. Chloroplasts collect light and convert that light to energy with the help of chlorophyll molecules and special enzymes.

Many plants, such as trees and flowers, have systems. These plants have a system of tubes they use to transport nutrients and water to different parts of the plant. plants all have similar parts, such as stems, leaves and roots.

The roots, for example, have several important functions. They pull water and minerals from the environment to the plant. This is why they grow down, because the water and minerals needed for growth are below the ground in the soil.

They also provide support and help a plant to the ground. Without a strong system, trees would not be able to stand tall and withstand high winds.

Roots can also store food and nutrients. A well-developed system can also prevent soil . Some roots are even edible. For example, the carrots we eat are the roots of the carrot plant!

Not all roots are underground, though. For example, water plants may have roots that float in the water. Epiphytes are plants that live in trees with roots that cling to tree branches.

There are even some plants that don't have roots at all. Remember: the plant kingdom is huge. It's hard for the human mind to grasp the number and wide variety of plants that exist on Earth.

Not all plants have systems. Mosses and liverworts, for example, conduct photosynthesis , but they don't have a classical plant structure like plants.

Mosses grow in damp places and soak up the water and minerals they need directly from their environment. They themselves to rocks and trees with rhizoids, thread-like growths that are not roots.

These and other examples of the simplest types of plants don't have roots. Green , for example, are single-celled plants that float on water surfaces. Many types of seaweed do the same. and seaweed absorb water and minerals from the water through all their parts.

# data[].attributes.attachment_link.description
Have you ever stopped to take a look at the world around you and think about how many different types of plants you see? A simple walk through your backyard or a local park will reveal hundreds of different types of plants.

# data[].attributes.attachment_link.description
Tulips in the wild grow in a variety of habitats in western Asia, from moist valleys to arid mountain slopes. In general, the summers are dry and even the valleys lose much of their moisture. You'll find tulips growing in grassy meadows, separate rather than in large clumps.

# data[].attributes.attachment_link.description
Sunflowers (Helianthus annuus L.) are large, erect blooms of the Asteraceae family. From dwarf varieties that reach about 4 feet in height to full-sized, towering cultivars that can grow 12 feet or taller, sunflowers enhance gardens and kitchens alike. Most of the 80 sunflower species are tolerant of temperatures ...

# data[].attributes.attachment_link.description
Availability Sunflower seeds should be sown in fertile, moist, well-drained soil that contains heavy mulch. They need full sun to grow properly and develop best in summer. They thrive when grown in large clusters, as they shade the ground and keep the roots cool and the ground damp for longer.

# data[].attributes.attachment_link.description
Nothing mysterious awaits those trying to learn the basic parts of a plant. Parts you've been aware of for as long as you can remember will give you most, if not all, six basic plant parts. Those parts are, from underground to farthest out, roots, stems, buds, leaves, flowers and fruits.