Question

More concentration of auxin in horizontally placed plants, under the influence of gravity, occurs in

• A. Upper side
• B. Lower side
• C. Both upper and lower side
• D. None of the above

Answer 1

The correct option is B Lower side

Auxin is a plant hormone that plays important role in the growth of stem and roots to gravity. Gravitropism is a plant growth response to gravity. Root shows positive gravitropism and shoot shows negative gravitropism. When plant is placed horizontally, more concentration occurs in lower side of the root and stem. This stimulates stem elongation and thus stem grows upwards. This inhibits root elongation and thus root grows downwards.

Thus, the correct answer is option B.