Homeostasis: tropism

Question 1

What is tropism

Answer 1

the growth response of a plant to an external stimulus. if the resulting plant growth is toward the stimulus, it is called a positive tropism. if the resulting plant growth is away from the stimulus, it is called negative tropism

Question 2

What is phototropism

Answer 2

a growth response to light caused by unequal distribution of auxin. there is less auxin on the side of the plant toward the light source than there is on the side away from the light source. because auxin can cause cell elongation, the cells on the side away from the light elongate, making that side of the stem longer. as a result, the stem curves in the direction of the light

Question 3

What is gravitropism (geotropism)

Answer 3

Roots generally show a positive gravitropism. the downward growth of roots into soil helps to anchor the plant and brings roots in contact with water and minerals. shoots show negative gravitropism upward away from gravity

Question 4

What is thigmotropism

Answer 4

a growth response to mechanical stimuli, such as contact with an object, another organism, or even wind. thigmotropism is evident in vines that twist around a nearby structure, such as a fence or tree