Question

Auxin synthesis occurs in
A) Root/shoot tips
B) Cortex
C) Xylem
D) Phloem cells

Answer 1

Auxin is a plant growth hormone that promotes growth via cell elongation, stimulates parthenocarpy, adventitious root formation and fights against abscission.

Complete answer
To answer this question, we have to know about auxin synthesis. In plants, Auxin synthesis occurs in young meristematic tissues such as roots and shoots tips and is transferred through the stem under the impact of gravity force. It is formulated from the amino acid tryptophan.

In the management of several growth and signaling molecules in plant life cycles, auxins play a crucial role and are vital for the success of the plant body.

It induces apical dominance and inhibits lateral buds' development. The lateral buds lay inactive as long as the apical meristem produces enough auxin. The auxin is no longer developed if the apex of the shoot is cut. This will trigger the dormancy of the lateral buds to break and begin to expand. The plant, in consequence, appears bushier.

Additionally, auxin also plays a significant role in phototropism. It creates a curve toward the light of the plant stem tip as it transfers itself to the darker side of the plant, allowing the cells there to rise higher on the lighter side of the plant than the cortical surface.

Hence the correct answer is option ‘A’.

Note: The shoot and root tip motion of Auxin is regarded as polar transport, which is a mechanism guided by energy (active transport). The most abundant and essential auxin that occurs and functions natively in plants is IAA. In the 1920s, the Dutch biologist Frits Warmolt Gone first defined auxins and their role in plant growth.