Plant Tropisms and Responses Quiz

Which of the following best defines "tropism" in plants?

• The movement of leaves during the day

• The process of seed germination

• A chemical reaction in plant cells

• A growth response towards a stimulus

Which hormone is primarily responsible for phototropic responses in plants?

• Auxin

• Cytokinin

• Gibberellin

• Ethylene

Gravitropism refers to a plant's response to:

• Light intensity

• Gravity

• Water availability

• Touch

Which of the following statements about phototropism is true?

• It causes roots to bend towards light

• It is independent of the hormone auxin

• It causes stems to bend towards light

• It is a negative response to light

Thigmotropism in plants is a response to:

• Chemical signals in the soil

• Temperature changes

• Water currents

• Mechanical stimulation or touch

Which plant structure primarily perceives gravitational forces?

• Root caps

• Leaves

• Stems

• Flowers

A positive tropic response is one in which the plant part grows:

• Away from the stimulus

• Towards the stimulus

• Perpendicularly to the stimulus

• In a spiral pattern

Which of the following is an example of a plant's nastic movement?

• Phototropism

• Gravitropism

• Thigmonasty (touch-induced rapid movement)

• Hydrotropism

In phototropism, uneven distribution of auxin results in:

• Equal growth on both sides of the stem

• Greater cell elongation on the side towards light

• Reduced growth on the side away from light

• Greater cell elongation on the side away from light

Which stimulus is most likely to induce a rapid closure response in the leaves of the sensitive plant (Mimosa pudica)?

• Mechanical touch

• Exposure to sunlight

• Increase in soil nutrients

• Changes in gravity