TropismsTropisms

C-Scope C-Scope

Unit 1Unit 1

Lesson 2Lesson 2

How do plants grow?How do plants grow?

From seeds or other plant partsFrom seeds or other plant parts They grow to continue speciesThey grow to continue species Seeds come from flowers on plants, all plants Seeds come from flowers on plants, all plants

have flowers you just might not be able to see have flowers you just might not be able to see them.them.

What do plants need to grow?What do plants need to grow?

WaterWater SunlightSunlight Correct TemperatureCorrect Temperature SpaceSpace FoodFood

Parts of a seedParts of a seed

Seed CoatSeed Coat CotyledonCotyledon RootRoot StemStem LeavesLeaves

How do seeds emerge?How do seeds emerge?

It responds to gravity, light, temperature, and It responds to gravity, light, temperature, and water.water.

When all conditions are right the seed will use When all conditions are right the seed will use the cotyledon to push up from the soil towards the cotyledon to push up from the soil towards the sun and the roots are pulled down by the sun and the roots are pulled down by gravity.gravity.

Plants in SpacePlants in Space

As early as 1984 NASA has been As early as 1984 NASA has been experimenting with plants in space.experimenting with plants in space.

The problem that NASA is trying to overcome The problem that NASA is trying to overcome are the tropisms.are the tropisms. HydrotropismHydrotropism PhototropismPhototropism GeotropismGeotropism ThigmotropismThigmotropism

HydrotropismHydrotropism

This is the plants reaction to water. This is the plants reaction to water. The roots will grow towards the waterThe roots will grow towards the water

This is a problem in space because the space This is a problem in space because the space shuttle cannot carry extra water to water the shuttle cannot carry extra water to water the plants (space and weight)plants (space and weight)

Since space is an issue, the astronauts have Since space is an issue, the astronauts have one water source and all the plants grow roots one water source and all the plants grow roots towards the water to save room.towards the water to save room.

Where do the water and nutrients Where do the water and nutrients come from?come from?

PhototropismPhototropism

NASA has done many experiments with light NASA has done many experiments with light and plants because Space can be a very dark and plants because Space can be a very dark place.place.

Phototropism is a plant’s reaction to light, Phototropism is a plant’s reaction to light, plants will grow towards light.plants will grow towards light.

GeotropismGeotropism Geotropism is the plants reaction to gravity. Geotropism is the plants reaction to gravity.

Usually roots grow down towards the center of Usually roots grow down towards the center of gravity and shoots grow towards the sun.gravity and shoots grow towards the sun.

The is very little gravity in space, it is called The is very little gravity in space, it is called microgravity.microgravity.

This presents a huge problem to plants since This presents a huge problem to plants since there is little light and almost no gravity.there is little light and almost no gravity.

NASA ExperimentsNASA Experiments

When NASA started doing experiments in the When NASA started doing experiments in the dark and in space many interesting things dark and in space many interesting things started to happen to the plants.started to happen to the plants.

The plants started to grow in circles. The plants started to grow in circles.

Back On EarthBack On Earth

ThigmotropismThigmotropism Plants response to touchPlants response to touch Plant will send out a feeler and when it touches Plant will send out a feeler and when it touches

something it will start to wrap around it.something it will start to wrap around it. It is how a plant climbs up thingsIt is how a plant climbs up things