Question

In the process of apical dominance lateral buds are unable to grow in the presence of apical buds this is due to

• A. more auxin in the lateral buds.
• B. less auxin in the lateral buds.
• C. more cytokinins in lateral buds.
• D. less cytokinins in lateral buds.

Answer 1

The correct option is A

more auxin in the lateral buds.

The correct option is A.

The explanation for the correct option:

1. To regulate the number of growing shoot tips and branches, a mechanism known as apical dominance occurs where the shoot tip prevents the axillary buds further down the stem from sprouting.
2. The apical bud prevents the lateral buds' expansion. The apex of the growing stalk is the primary source of auxin, which is then carried down to other plant components to the lateral buds. The term for this is apical dominance.
3. Auxin concentration falls when the apical bud is removed, allowing lateral buds to expand. Auxin affects the lateral buds differently than the apical buds.
4. The growth of apical buds is driven by a certain concentration of auxin, and they are unable to grow over that concentration.
5. In the apical dominance process, lateral buds cannot develop when an apical bud is present.

The explanation for the incorrect options:

Option B:

1. According to the direct idea, buds are inhibited from growing as auxin produced at the shoot apex travels down the stem and enters them.
2. This idea contends that auxin produced apically prevents buds from producing the auxin required for growth.

Option C:

1. Nutrients travel preferentially in that direction when cytokinin is present.
2. They support the growth of lateral buds when used on them, even when an apical bud is present.
3. As a result, they function in opposition to auxin, which encourages apical dominance.
4. High cytokinin concentration has the effect of suppressing apical dominance and allowing axillary buds to grow.
5. If the shoot tip has developed several side shoots or axillary shoots, these can be inoculated on newly prepared media that contains cytokinin.

Option D:

1. High cytokinin concentration has the effect of suppressing apical dominance and allowing axillary buds to grow.
2. If the shoot tip has developed several side shoots or axillary shoots, these can be inoculated on newly prepared media that contains cytokinin.

Final answer: In the process of apical dominance lateral buds are unable to grow in the presence of apical buds this is due to more auxin in the lateral buds.