FORESTRY
PLANT AND WOOD ANATOMY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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auxins
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ethylene
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cytokinins
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insulin
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Detailed explanation-1: -The term auxin is derived from the Greek word auxein, which means “to grow.” Auxins are the main hormones responsible for cell elongation in phototropism (movement in response to light) and gravitropism (movement in response to gravity).
Detailed explanation-2: -auxin distributions are responsible for phototropic responses-i.e., the growth of plant parts such as shoot tips and leaves toward light. In certain cases auxin may be destroyed on the illuminated side, and the unilluminated side with more auxin elongates, causing the shoot to bend toward the light.
Detailed explanation-3: -Gibberellins (GAs) stimulate plant elongation, promote flowering and release seed/tuber dormancy. It is believed that gibberellins are produced and function in the same cell acting as an autocrine signal.