Plant Development and Light
Let's learn about plant development with and without light.
Here is a drawing I made of corn shoots growing in the light and in the dark.
Developing in the Dark
When there is no light plants can grow. They just look a bit different. The roots and shoots of plants stretch longer. They search for the light. They even search for surfaces to touch and follow as they grow. Until plants are exposed to light, they are dependent on the nutrients present in the fleshy endosperm of the seed to grow. What is endosperm? When you eat popcorn, the fleshy endosperm is the puffed fluffy part that we love to eat. Here is a picture of popped endosperm (popcorn).
If you provide a plant with more nutrients, plants can grow in complete darkness for quite some time. These dark-grown plants undergo a developmental process called skotomorphogenesis. Here is this big fun word written out with blue and red.
In the darkness, plants will grow roots and stems and leaves. The leaves are white or pale yellow. They will still make new leaves, but the leaf blades will not expand nor turn green. These plants are called etiolated. Here is a picture I drew of an etiolated corn shoot.
Plant Development in Light
Once a plant reaches the light, they undergo the process of photomorphogenesis. I wrote out this big fun word, too.
Dark to Light
When a plant moves from darkness into the light, it changes! It's like a light switch is turned on. Leaves turn green and begin to get big. They become vitalized. Here is a picture I drew of a vitalized corn shoot.
As the plant turns green, it is able to produce its own sugars and carbohydrates through photosynthesis. That's another big word!
Cells and Photosynthesis
Plants are made up of cells. Each plant cell has a wall. Inside cells are organelles. Let's learn about just a few of these today: nucleus, vacuole, and plastid. The nucleus holds the plans for the whole plant. A vacuole is where a plant stores important things for later, like water and minerals. Plastids are organelles, too. The kind of plastid that harvests light is called a chloroplast. I drew the chloroplast bigger than usual inside this plant cell so it's easier to see. Can you find the chloroplast? It is green and has lots going on inside of it.
When plants develop in the dark, they have plastids, too. Rather than big green chloroplasts, these plastids have no color of their own. A couple of plastids types that are found in dark-grown plants are etioplasts and amyloplasts. Etioplasts are filled with fat while amyloplasts have starch. Amyloplasts are pretty special to me because they help a plant sense gravity.
Art Activity
Now that you have learned all of these exciting things about plant and light, what art can you make?
Get out your watercolors, crayons, pencils, clay, and get creative!
Here is a painting by our 2 year old. She played with green, yellow, and orange paint.
Do you have a dark place like a closet or a cabinet? Do you have a window or a light? Do you have some seeds? You can plant some in the dark and some in the light. All you need is a paper towel and a container. Sprinkle the seeds on the paper towel, give them some water, put them in their window or cabinet and see how they grow!
Other Lessons About Plants
Do you want to see other blog posts that I have written about plants?
Our senses and plants: http://steamma.blogspot.com/2022/03/our-5-senses-and-plants.html
Seed to seed, see what you get:
Pepper plants in space: http://steamma.blogspot.com/2020/05/space-chile-grow-pepper-plant-challenge.html
Marigold plants in space and in your garden:
Using plants to work on scientific description:
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