Our 5 Senses - and Plants!

March 27, 2022

Our 5 Senses - and Plants!

A garden can be a feast for the senses.

Let's explore the plants in our gardens with our senses, then explore how plants sense their environment.

Smell

Some plants smell beautiful, like this rose.

We smell with our nose.

Here are some cards we made with a picture of a nose, the word nose, and the word smell.

Touch

Some plants feel soft, like this silver ragwort (Jacobaea maritima).

We touch with our skin, like the skin on our fingertips. Here are some cards we made to learn the words skin and touch. We drew a hand with skin, and wrote the words skin and touch.

Taste

Some plants taste remarkable, like this tart little lime.

And like the deliciously spicy peppers that grew on the International Space Station. (Images.nasa.gov)

Here is a photo of Astronaut Megan McArthur with a space taco that she made with space-grown peppers. (Images.nasa.gov)

We taste with our mouth. Here are the cards we made for taste.

See

It's fun to see flowers with high contrast like these creamy yellow flowers with dark brown accents on three of their six petals. This is Dietes bicolor, also known as African yellow iris.

We see with our eyes. Here are the cards we made with a picture of eyes, the word eyes, and the word see.

Hear

When we listen in our garden, we hear birds. What birds do you hear in your garden?

A flock of ibis visited our garden today. They enjoyed picking at the ground for bugs. Here is a photo of an Ibis taken at Kennedy Space Center, from the NASA image gallery.

Here is a video that shares 3 minutes of white ibis bird songs and calls from Planeta Azul, on YouTube: https://youtu.be/PreZfB74rjA

Would you like to become better at identifying birds by their calls? Here is a link to an article with tips.

https://www.allaboutbirds.org/news/how-to-listen-to-bird-song-tips-and-examples-from-the-warbler-guide/

Crunch!

We found some fallen leaves. Such a satisfying experience to hear and make that crunch with fallen leaves.

We hear with our ears. Here are the three cards we made for hearing.

Sensing in Plants

We humans can see, hear, smell, taste, and touch. Did you know that plants have senses, too?

Photo

Plants don't have eyes, but they do have photoreceptors, which allow them to notice and respond to light.

Check out this 3D model of a phytochrome from the Protein Data Bank. You can twist it around to see it from every angle. https://pdb101.rcsb.org/learn/structural-biology-highlights/phytochrome

Mechano

Plants don't have ears, but they do have mechanoreceptors which are sensitive to sound waves, and they can grow in response to noise.

Want to read an open-access scientific paper that reviews past work with sound perception by plants? Here is a link. https://www.frontiersin.org/articles/10.3389/fpls.2018.00025/full

Chemo

Plants cannot smell or taste, but they can pick up volatile chemical signals, and adjust their growth accordingly. Want to learn more about a plant that can smell? Here is a fun illustrated explanation from Kurlwich Wonders on National Public Radio. https://www.npr.org/sections/krulwich/2012/05/24/153583873/do-plants-smell-other-plants-this-one-does-then-strangles-what-it-smells

Thigmo

Even though a plant doesn't have skin like us, it has a sense of touch! When the tendril of a pea plant touches a pole, it twists around it to climb higher. When we pet the leaf of a sensitive plant (Mimosa pudica) the leaves close up on themselves. Here is a link to a video made by a slow motion videographer (not me!) that shows the motion of a sensitive plant: https://youtu.be/LuOGOQ_vnDo

Tropisms

Tropism is the general term for a plant's response to stimulus. Thigmotropism is the response of plants to touch. Phototropism is the response of a plant to light. Chemotropism is the response of a plant to chemicals. Gravitropism is the response of a plant to gravity. When a plant cannot sense gravity, it can still react to light, touch, and chemical signals.

Simple Gravitropism Experiment

Do you have a house plant? Pick up the pot and put it on its side someplace dark. Leave it there for a few hours, maybe even overnight. Then come back and check on your plant. Has it adjusted its growth? It looks funny, doesn't it?

Don't worry, just put back upright and it will adjust again.

Here is a photo of our little houseplant Syngonium just after it was placed on its side. I wrote the word gravitropism on a card and placed it in front of the plant for the children to discover. Before I set the plant on its side, I placed a small straight bamboo skewer in the pot so I would have a reference for what a straight stem would look like.