Plant Structures and Tropisms

Tony wanted to see if he could make the roots of a plant grow up instead of down. After several tries, he found that the roots always grew down. Nothing he or his teacher did made the roots grow up. What keeps the roots from growing up?

• The roots need water.
• Sunlight hits the plants.
• Gravity pulls on the roots.
• There is plant food in the soil.

Tags

NGSS.MS-PS2-5

This is a survival technique where an organism, usually a plant, is capable of directed physical movement or growth in response to a specific stimulus; such as light, gravity, water, or contact.What is the survival technique described above that is used by plants?

• locomotion
• migration
• pseudopodia
• tropism

Tropism is a biological phenomenon where an organism, usually a plant, is capable of directed physical movement or growth in response to a specific stimulus. What is the term for a plant's movement or growth in response to gravity?

• geotropism
• hydrotropism
• phototropism
• thigmotropism

Seasonal changes bring about scenes like this one. Plant cells respond to changes in _________________ and as a result, photosynthesis slows and leaves change color.

• day length and available oxygen
• carbon dioxide and glucose levels
• light intensity and temperature change
• available oxygen and temperature change

Mr. Walker plants a new plant next to a tall tree in his yard. It is partly in the sun, but is mostly in the shade. He notices that it is growing with all of its leaves on one side. Why is the plant growing this way?

• It's dying
• It's trying to get sunlight
• It's trying to stay in the shade
• It wants to be closer to the tree

The plants growing high in the tree canopy send out roots. The roots are searching for water vapor in the humid air of the forest. This response that helps aerial plants find water is called

• germination
• hydrotropism
• phototropism
• thigmotropism

Which statement describes how plants respond to heat?

• Leaves bud in warm weather.
• Roots grow upward in hot soil.
• Petals change shape in hot air.
• Stems bend away from warm areas.

The days are getting shorter and colder. These trees are responding to the change. Their leaves change color and will soon fall off. Losing leaves during the winter is the response to the external environment called

• dormancy
• hibernation
• hydrotropism
• phototropism

In nature, plant roots grow down, and plant stems grow up. For a class experiment, a teacher plants a seed in an upside-down pot. The pot hangs from the ceiling. Soil cannot fall from the pot. What happens to the stem of a plant that is grown upside down?

• The stem will not grow at all.
• The stem will grow out the hole and then up.
• The stem will grow out the hole and then down.
• The stem will grow through the dirt by the roots.

Sunflowers seem to follow the path of the sun as it travels across the sky during the day. Plants bending toward or following light is a response called

• hydrotropism
• photosynthesis
• phototropism
• thigmotropism