Plant Responses to the Environment: Tropisms and Defenses

The video explores plant tropisms, which are movements or growths in response to stimuli like light, gravity, and water. It explains how auxin influences these tropisms, such as phototropism and gravitropism. The video also covers plant circadian rhythms and phenology, detailing how plants respond to day/night cycles and seasonal changes. Additionally, it discusses plant defenses against herbivory, including physical and chemical strategies to deter herbivores.

What is the role of auxin in plant tropisms?

• It helps in seed dispersal.

• It provides nutrients to the plant.

• It helps plants grow towards or away from stimuli.

• It protects plants from herbivores.

Which type of tropism involves plant growth in response to light?

• Thigmotropism

• Phototropism

• Gravitropism

• Hydrotropism

How do plants exhibit positive gravitropism?

• By growing upward against gravity

• By growing downward towards gravity

• By growing towards light

• By growing away from water

What is the significance of plant circadian rhythms?

• They assist in seed dispersal.

• They regulate day/night cycles and plant behaviors.

• They help plants grow in response to touch.

• They protect plants from herbivores.

What triggers the blooming of the first wildflowers in spring?

• Decrease in daylight hours

• Increase in soil moisture

• Angle of the Sun rising above a certain point

• Rise in temperature

Which of the following is a physical defense mechanism in plants?

• Production of toxins

• Presence of thorns or spines

• Release of growth hormones

• Emitting a strong odor

How do some plants deter insect herbivores using chemical defenses?

• By producing sweet nectar

• By mimicking insect growth hormones

• By growing faster

• By changing leaf color