Responses
Mary put a plant into a box with a hole in it. After a week, Mary observed that the plant was now leaning towards the hole. What could have caused this change?
Phototropism
The plant was responding to sunlight.
Seeds need water in order to germinate.
True
How does growing towards light help a plant?
It allows the plant to gain sufficient light for photosynthesis to produce glucose for energy
When the weather gets colder, some plants become ____.
dormant
If I plant four seeds in four different directions, how will the roots grow?
All will grow down towards gravity (positive gravitropism)
When an insect lands on a Venus Flytrap, it closes up. What is the plant responding to?
Thigmonastic response - Touch
A seed will not germinate if it is planted upside down.
False - it uses auxin and gravity to grow shoots upward and roots downward
Why do venus fly traps snap close when a fly lands on them
To gain nutrients that it is unable to gain from the soil usually
Some plants require a certain amount of ___ to make fruit.
cold weather - this is called cold stratification
Name one plant that responds to touch.
Mimosas, venus flytraps, vines and climbing plants.
Which part of the environment makes a morning glory plant respond by opening and closing its flowers?
Light
Plants respond to cold weather by hibernating.
True - this is called dormancy
How do leaves and plants respond to light?
Auxin will move to the dark side of the plant where it elongates the cells to bend toward light
In the winter, some plants will stop making ___ through ____.
food, photosynthesis - this allows them to reserve energy
How do climbing plants and vines respond to touch?
Auxin accumulates on the non-touching side of the stem, resulting in the cells on the non-touching side elongating and causing the plant to bend toward what it touching/climbing up.
What is the name of the plant hormone that creates trophic responses
Auxin
Some plants respond to touch by growing around the thing it touches.
True - this is called thigmotropism and plants save energy by using another structure for support to grow higher
Some plants open their leaves during the day to collect sunlight and close their leaves at night to prevent ___.
water loss
____ means alive but not active.
dormant
Why do a mimosa plant's leaves fold up after being touched
It reduces the area of the leaves exposed which prevents damage from herbivores, thus ensuring the leaves are still able to absorb light and photosynthesize.
A home-owner noticed that his flowers were starting to bloom as the spring had started, what is the environmental cue causing this?
Change in day length - photoperiodism
Which of the following statements about a seedling is true?
A. The stem show a positive gravitrophic response
B. The roots show a positive gravitrophic response
C. The stem show a negative phototrophic response
D. The roots show a negative hydrotrophic response
B. The roots show a positive gravitrophic response
How do the roots in a germinating seed grow downward?
Auxin accumulates at the bottom side of the root, here it inhibits cell elongation so the top side grows more causing the root to bend downward
Abscission - allows the plant to reserve energy over winter when light levels are lower.
Why would roots want to grow toward the pull of gravity?
To grow downward to find water and nutrients essential for photosynthesis and growth.