Archives For botany for kids

Leaves are green. There are very few exceptions in healthy living plants, and most of the exceptions are partially green with red, yellow, orange, or white patterns; or they look white, but upon closer inspection they are actually whitish, bluish-green, and not pure white. The pigments that give all leaves their color are essential for the plant’s ability to harness energy from the sun and make sugars in the process we know as photosynthesis.

But every once in a while, a completely white seedling sprouts from a seed. This happened with some basil I grew a few years ago. 

 

PHOTO: this picture shows two seedlings, one has two green seed leaves and the other is white and only half as big.

The green and albino seedlings came up at the same time, but the albino seedling never grew true leaves, and eventually withered and died.

My albino basil survived only a few days. Without any chlorophyll—the green pigment necessary for photosynthesis—this seedling was doomed. That is the case with all albino plants. The gene mutation that gives rise to albino plants is fatal to the plant, because without the ability to make sugars, the plant runs out of energy to live.

So when I was perusing the online Burpee seed catalog and came across “variegated cat grass” I was curious. VERY curious, and perhaps you are, too.

PHOTO: a potted plant of white grass leaves.

How can this albino plant survive? (Photo permission from W. Atlee Burpee Company)

I had several questions: 

  • The term “variegated” implies that the leaves would be striped or multicolored, but in the picture it appears that there are all white leaves. What will this grass actually look like?
  • How long will it take to sprout?
  • How easy it to grow?
  • Is there enough green on those leaves for the grass to survive or will it die off like my basil?
  • If it does survive, how long can I keep it growing?

And most importantly:

  • Would this make an awesome science activity for students in the classroom and at home to investigate the importance of chlorophyll in plants?

There was only one way to find the answers. I ordered the seeds and grew some variegated cat grass in our nature lab at the new Learning Center. You can do this in your classroom to find answers to my questions and your own. 

Before I give you directions for growing cat grass, you may be wondering:

What IS cat grass?

The cat grass you may have seen sold in pet stores is usually a type of wheat, or Triticum. Our “variegated cat grass” is a type of barley (Hordeum vulgare variegata). Both are cereal grains that have been cultivated as food for hundreds of years. Both are sold commercially as cat grass because some cats like to chew on the leaves. Not being a cat owner, I don’t know if cats actually like this stuff, but apparently it sells.

Variegated barley was the result of science experiments on genetic mutations in barley seeds in the 1920s. The hybrid barley seeds have been packaged and sold by different seed companies because…well, they’re attractive and intriguing—they caught my attention.

How to plant cat grass, barley, wheat, or any grass seeds

You need:

  • A container that will hold soil at a depth of at least 2 inches; drainage holes are best, but not necessary
  • Variegated cat grass seeds (sold as “cat grass, variegated” and available at Burpee and other seed suppliers)
  • Potting soil
  • Water
  • A warm, sunny location for your plants

 

PHOTO: Twelve plants have sprouted, one green, three green and white striped, and the rest all white.

In less than a week, a few more than half of the twenty variegated cat grass seeds planted in this 4-inch pot grew to 4 – 6 inches tall. The taller plants are ready for a trim.

Fill the container with moist potting soil. Spread seeds on the surface of the soil. Cover seeds with a thin layer of moist soil and tamp the soil down so that most of the seeds are covered. It’s all right if you can see some of the seeds through the thin layer of soil. Place in a warm, bright location. The seeds will sprout in a few days, but may take a week depending on the room temperature.

If students plant their own individual pots, have them place 20 – 30 seeds in each 3-inch container. The seeds I bought came 300 to a pack, so that means you need at least two (maybe three) packs to have enough for everyone in the class.

PHOTO: most of the grass is all white, but there are nine or ten all or partially green leaves.

Half of the 100 seeds planted in this 8-inch pot have sprouted, and more should be coming up soon.

You can also use the whole pack in a 8- to 10-inch container, or even spread more seeds in a foil baking pan filled with soil to grow a carpet of grass. The more densely you plant the seeds, the closer the plants will grow together and it will look and feel more like a healthy lawn. A sparser planting makes it easier to observe individual plants. It’s up to you how you want to do it, really.

Keep the grass in a warm, sunny location. Water when dry, but do not allow it to dry out. When the grass leaves are more than 3 inches tall, use a sharp pair of scissors to trim them to a uniform height just as you would mow a lawn. This will prevent the grass from going to seed and keep it alive longer. You can plant new seeds in the same planter to revitalize in two to three weeks when it starts looking a little tired.

Now the REAL science part: 

Whether you make a single classroom planter or have each student plant her own pot, observe your variegated cat grass for the next four to six weeks, or even longer. Keep it watered and trimmed. Measure its growth. Take photos or sketch it to record how it grows and changes. Ask your own questions and try to find answers, and ultimately reach a conclusion about what happens to white plants. If you and your class are really interested, plant some more cat grass and change the procedure to test your own ideas. It’s that easy to do plant science in your classroom.

Want more albino plant science? Read on.

More activities for inquiring minds

You can experiment with other genetically modified albino seeds available through science supply companies.

PHOTO: A packet of genetically modified corn seeds and instruction booklet

Seed kits enable you to investigate different genetic traits, including the albino mutation.

Carolina Biological Supply Company sells hybrid corn that will grow white leaves and stems. I have planted these seeds and they work pretty well, but require a bright window or light and a warm environment to sprout successfully. A classroom kit contains soil, planting trays, and 500 seeds for a classroom investigation, and costs about $100. You can order just the seeds in packs of 100 genetic corn seeds that are all albino (90 percent of the seedlings will grow to be albino) for $18.50, or a green/albino mix—which means about 75 percent of seedlings will be green and 25 percent white, for $10.50. The latter enables you to compare the mutation to the normal strain. 

PHOTO: Ten white corn seedlings are a few inches tall.

Five days after planting, albino corn seedlings are beautiful, but ill-fated.

Nasco sells seeds and kits to investigate albino plants. Their “Observing the Growth of Mutant Corn Seeds” kit serves up to 40 students and costs $62.50. Nasco also has albino tobacco seeds with 3:1 green to white ratio, 1,200 seeds for $12.05. Tobacco seeds are smaller, and therefore more difficult for little fingers to handle than corn or barley. I have never tried growing them, but that might be my next science project this fall.

PHOTO: eight inch glass planter with green grass and label that says: Cat Grass (Barley).

After a two months, my densely planted variegated cat grass is thriving at the nature lab, even though it no longer resembles the catalog photo.

The answer to my question? Yes! This is an awesome science activity for students because it’s easy and demonstrates something really important—in fact, something essential to our existence!

You don’t need to purchase the fancy kits to investigate why plants are green. You can get a lot of good science learning out of a pack of variegated cat grass. All you really need to do is look around you and notice the colors in nature. Do you see white leaves anywhere? If you do, then there is probably a science investigation waiting for you.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Gardeners and farmers know that healthy plants need good soil and the right amounts of both water and sunlight. But green roofs are intentionally built with an engineered soil-like substance that more closely resembles a pile of rocks than rich, moist potting soil.

To make matters worse, the tops of buildings are often blindingly sunny and very hot in the summer. So how do plants like grasses and wildflowers survive in this type of harsh environment?

PHOTO: Cactus and allium grown on green roof.

Cactus and other succulents retain water in their tissues. Ornamental onion (Allium) species have underground bulbs that help them get through cold winters and dry summers.

Not all plants will grow on a green roof, even in the temperate Midwest. Most plant species that are successful in the desert-like habitats of green roofs have beneficial adaptations that allow them to absorb and store water and nutrients. Some have succulent leaves with thick waxy coatings to prevent water from evaporating. Others have roots that grow horizontally rather than vertically to maximize the areas from which they absorb water and nutrients. Some use a modified type of photosynthesis to prevent water loss during the hottest and driest part of the day. Still others use bulbs or underground tubers to store nutrients during the long cold winters. Some species may even form partnerships with special fungi in the soil that help their roots with more effective absorption.

While plant species evolved to develop these various adaptations on the ground, such traits serve the individual plants very well in the harsh environment of a green roof. The next time you visit a green roof, you might see a striking diversity of species but you won’t see any wimps. No, these plants are both beautiful and tough. 

PHOTO: Shortgrass prairie plants grown on a rooftop garden at shallow depths.

Even in very shallow soil and full sun, some plants that normally grow in shortgrass prairies are able to grow and reproduce. (This is from some of my research at Loyola University.)

PHOTO: PCSC green roof in summer 2015.

Plants can be both tough and beautiful on green roofs. (This photo is of the Plant Science Center last summer.)

Find more of the best plants for green roofs on our Pinterest board, and see Richard Hawke’s Plant Evaluation Notes for the plants that performed best on our green roof.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Those of us who are Star Wars fans know just how powerful genetic cloning can be. 

Obi-Wan Kenobi’s discovery of a secret clone army illustrated the power of advanced cloning technology. That army of genetically identical clone warriors went on to become the face of the epic Clone Wars. Meanwhile, in a galaxy much closer, plants are also equipped with the ability to copy themselves as a form of reproduction. This form of asexual reproduction is very common in the natural world, and just as powerful to an ecosystem as a clone army is to a galaxy. 

PHOTO: Clone trooper.

This clone may not take over your Garden…

PHOTO: Red Monarda (beebalm).

…but this Monarda might!

Clonality is a form of plant growth that results in genetically identical individuals.

Unlike in sexual reproduction, clonal individuals often spread horizontally below ground via unique root systems. Above ground, these plants appear to be distinct individuals, but beneath the soil surface, they remain connected, as clones of the same original plant.

The Pando, or "Trembling Giant," is a colony of clonal quaking aspens roughly 80,000 years old, in Fish Lake, Utah.

The Pando, or “Trembling Giant,” is a colony of clonal quaking aspens (Populus tremuloides), roughly 80,000 years old, in Fish Lake, Utah. All the trees are a single living organism sharing one massive root system. Photo by By J Zapell via Wikimedia Commons.

From a plant’s perspective, there are many benefits to clonal growth. For example, in an environment with limited pollinators to facilitate sexual reproduction, it might be better to take matters into your own hands and make a copy of your already awesome self. On the other hand, a vulnerability in one clone (for example, to a fatal fungal outbreak) is just as likely to affect all of the other clones, because they share the same genetic makeup. It is important to note that there are ecological downsides to clonality as well. Many invasive species do well in foreign environments because asexual reproduction enables them to reproduce very quickly. Thus, just as we see in Star Wars, clones can either be a powerful asset or a potent enemy.


Abigail WhiteAbbey White is a graduate student working with Andrea Kramer, Ph.D., and Jeremie Fant, Ph.D., developing genetically appropriate seed mixes of vulnerable plant species for restoration.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

Most plants hate saltwater. Pour saltwater on your houseplants and, a little while later, you’ll have some wilty plants. But mangroves can grow—and thrive—in saltwater.

You may have seen mangroves if you’ve been to the Florida Everglades or gone to an island in the Caribbean. Mangroves are trees that live in tropical, coastal zones and have special adaptations for life in saltwater. One of these adaptations is in how they reproduce: mangroves don’t make seeds. Instead, they make living, buoyant embryos called propagules (prop-a-gyule).

Mangrove propagules come in different shapes and sizes. Each species has its own unique propagule.

Mangroves produce a huge number of propagules the same way an oak would make hundreds of acorns.

Mangroves produce a huge number of propagules the same way an oak would make hundreds of acorns.

These relatively small propagules could become giant red mangrove trees.

These relatively small propagules could become giant red mangrove trees.

Black mangrove propagules on a branch; their outer coating will dissolve on their journey downstream.

Black mangrove propagules on a branch; their outer coating will dissolve on their journey downstream.

Propagules come in different shapes and sizes. These are from a tea mangrove (Pelliciera rhizophorae) tree.

Propagules come in different shapes and sizes. These are from a tea mangrove (Pelliciera rhizophorae) tree.

Normally, trees reproduce with seeds. You’ve probably seen the whirlybirds of maples and acorns of oaks. These seeds can go dormant. They are basically “asleep” or hibernate until something—water, temperature, or physical damage—wakes them up, allowing them to start growing months or years after they are produced.

Here I am with a couple of mangrove specimens. These roots are in water at high tide, but exposed at low tide.

Here I am with a couple of mangrove specimens. These roots are in water at high tide, but exposed at low tide.

Propagules, on the other hand, don’t have that luxury—they fall off their parent tree, ready to start rooting and growing a new tree. Nature has provided an amazing way for the mangrove seeds to move away from the parent tree: they float.

As the propagules float through the water, they shed their outermost layer and immediately start growing roots. The clock starts ticking as soon the propagules fall—if they don’t find a suitable place to start growing within a certain amount of time, they die. If a mangrove propagule ends its journey at a location that’s suitable for growth, the already-rooting propagule will send up its first set of leaves—cotyledons.

Ocean currents can take propagules thousands of miles away from where they started. A mangrove’s parent tree might be around the corner or around the continent.


Dr. Emily DangremondDr. Emily Dangremond is a postdoctoral researcher at the Smithsonian Environmental Research Center and a visiting scientist at the Chicago Botanic Garden. She is currently studying the ecological and evolutionary consequences of mangroves responding to climate change at their northernmost limit in Florida.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org

When buckthorn moves in to the ecosystem, it dominates.

Imagine a friend invites you to a dinner party, promising a delicious spread of food and libations. You arrive, excited and hungry, only to find nothing but raw kale, brought by an uninvited guest. Regardless of your feelings about kale, this would be pretty underwhelming. The other guests are obviously disappointed about the monotonous spread. Most people leave, and because most people aren’t eating the kale, the kale continues to dominate the party. Even if someone brought in better foods that more people enjoy, there is no room on the tables. The kale is everywhere!

PHOTO: Buckthorn (Rhamnus cathartica).

Common buckthorn (Rhamnus cathartica)

While not a perfect analogy, this anecdote relays the reasons why buckthorn invasion is detrimental to forest ecosystems. The dinner guests are like the other plants and animals that usually live in the woods. They have certain dietary needs, and if those needs cannot be met, they will have to leave and find another place to live. The more one species dominates (kale, or in many local forests, buckthorn) the fewer species can live there, leading to the ecological equivalent of a party that ends at 8:30, just as everyone was arriving. While it may be true that one person at the party really likes kale, it’s hardly fair for the preferences of that person to supersede everyone else’s needs. In the case of buckthorn, many have opposed its removal because that denies robins a berry that they enjoy. However, keeping the buckthorn (which doesn’t belong there in the first place) is like keeping all of the kale on the tables and not allowing for other foods to be served just for that one person. Even more frustrating, the person that likes kale has plenty of other dietary options. Kale isn’t even their favorite food!

PHOTO: The McDonald woods shows healthy filtered sunlight and native plant understory growth after buckthorn removal.

The McDonald woods shows healthy filtered sunlight and native plant understory growth after buckthorn removal.

To many people, the idea of cutting down trees to help forests grow stronger is counterintuitive. But buckthorn is no ordinary tree. It is an invasive species, meaning that it doesn’t belong in Chicago area forests, and it steals resources from the plants that are supposed to live here. So remember, when you hear people talking about cutting down buckthorn, they are actually doing it to make the habitat healthier and more inclusive in the long term. They are working to replace the kale at the party with better food and drinks, ensuring that all the guests that were invited can have a good time, staying up until sunrise.

Read more about our ongoing buckthorn battle, and see the difference removal makes in restoring an ecosystem.


Bob Sherman

Bob Sherman is an undergraduate studying environmental science at Northwestern University. His research interests include prairie restoration and how abiotic factors impact prairie and forest ecosystems. He hopes that his research will have a positive impact on ecosystem restoration and management.


Students in the Chicago Botanic Garden and Northwestern University Program in Plant Biology and Conservation were given a challenge: Write a short, clear explanation of a scientific concept that can be easily understood by non-scientists. This post is part of their series.

©2016 Chicago Botanic Garden and my.chicagobotanic.org