Why does the stem bend towards light in phototropism?
Answer and explanation
Correct answer: Unequal distribution of auxin causes unequal cell growth
The governing concept is phototropism caused by unequal growth. When light comes from one side, auxin becomes distributed unevenly in the shoot. In a typical shoot, the shaded side receives more auxin and its cells elongate more than cells on the lighted side. This difference in elongation produces curvature, so the stem bends toward the light. Blood, roots pulling light and stopping photosynthesis do not explain it.
Frequently asked questions
What is the correct answer to this question?
Unequal distribution of auxin causes unequal cell growth
Why is this the correct answer?
The governing concept is phototropism caused by unequal growth. When light comes from one side, auxin becomes distributed unevenly in the shoot. In a typical shoot, the shaded side receives more auxin and its cells elongate more than cells on the lighted side. This difference in elongation produces curvature, so the stem bends toward the light. Blood, roots pulling light and stopping photosynthesis do not explain it.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: World of Living. Topic: Control and Coordination.
