What is the role of auxin?

Auxins promote stem elongation, inhibit growth of lateral buds (maintains apical dominance). Auxin is a plant hormone produced in the stem tip that promotes cell elongation. Auxin moves to the darker side of the plant, causing the cells there to grow larger than corresponding cells on the lighter side of the plant.

How does auxin influence Gravitropism?

Gravitropism is based on the redistribution of auxin in the elongation zone of the developing root. If the root is not growing vertically downward, then auxin accumulates in the lower parts of the root, inhibiting cell elongation and causing the root to bend in the direction of gravity.

How does auxin cause phototropism?

Auxins also play a part in phototropism, an occurrence that involves plants bending or moving away from light. The extra auxin present on the shaded side promotes more cell division and elongation, causing the plant to bend towards the sunlight after this lop-sided growth. …

Where are statoliths in plants?

A membrane-bound group of starch grains (see amyloplast) in plant cells that is believed to act as a sensor to gravity. Starch statoliths are found in cells at the root tips and in the tissues close to the vascular bundles in shoots; under the influence of gravity they sink to the bottom of the cell.

What are statoliths made of?

Equilibrium organs are called statocysts. They contain statoliths (stones) made with dense material such as calcium or magnesium salts crystals which are in contact with specialized cells.

What is the main role of auxin in plants?

Auxin is a key regulator of plant growth and development, orchestrating cell division, elongation and differentiation, embryonic development, root and stem tropisms, apical dominance, and transition to flowering.

What is the purpose of auxins in plants?

Auxins are a powerful growth hormone produced naturally by plants. They are found in shoot and root tips and promote cell division, stem and root growth. They can also drastically affect plant orientation by promoting cell division to one side of the plant in response to sunlight and gravity.

How is auxin responsible for phototropism and Geotropism?

Both phototropism and geotropism are controlled by the distribution of auxin within the plant cells: In geotropism, auxin will accumulate on the lower side of the plant in response to the force of gravity. In phototropism, light receptors (phototropins) trigger the redistribution of auxin to the dark side of the plant.

What is the best explanation of how auxin directs phototropism in plant shoots?

When a plant senses a directional light stimulus it redistributesits auxin molecules to the side that is further away from the light. As a consequence, the plant cells that are further away from the light experience a greater auxin concentration and grow faster, causing the shoot to bend towards the light.