DENDROLOGY AND SOCIETY
PLANT CLASSIFICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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roots grow upwards
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roots grow downwards
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roots stop growing
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None of the above
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Detailed explanation-1: -The roots grown downward in the direction of gravity, which is positive gravitropism, and the shoot grows upward away from gravity, which is negative gravitropism. The reason plants know which way to grow in response to gravity is due to amyloplasts in the plants.
Detailed explanation-2: -Gravity sensing involves the sedimentation of starch-filled plastids (statoliths) within the columella cells of the root cap (the statocytes), which triggers a relocalization of plasma membrane-associated PIN auxin efflux facilitators to the lower side of the cell.
Detailed explanation-3: -Geotropism is a type of tropism where plants show some growth in response to gravity. Roots growing downwards is an example of geotropism.