Question

In the process of apical dominance, lateral buds are unable to grow in the presence of apical buds. This is due to
A. Less amount of cytokinins in lateral buds
B. More amount of cytokinins in lateral buds
C. Less amount of auxin in lateral buds
D. More amount of auxin in lateral buds

Answer 1

Hint: Apical meristem can be found in the tips of roots and shoots. Lateral buds grow due to the presence of cytokinin. They encourage the production of nutrients, which helps to slow the leaf senescence.

Complete Answer:
Growth in plants is controlled by chemical substances called plant growth regulators (PGR). Various groups of PGRs are found in plants, mostly belonging to five categories: auxins, gibberellins, abscisic acid, cytokinins, and ethylene. Plant growth regulators are synthesised in various sections of the plant and they regulate differentiations and development.

Natural cytokines are synthesised in regions where accelerated cell division occurs, e.g. root apices, shoot buds and young fruits. It helps to produce chloroplasts in leaves, new leaves, lateral shoots and adventitious shoots. Cytokinins are able to overcome apical domination.

The term 'auxin' is applied to indole-3-acetic acid (IAA) and other natural and synthetic compounds with growth-regulatory properties. In general, they are formed by the growing apices of the stems and roots, where they move to the other regions. In most plants, the growing apical bud prevents the development of lateral buds. This process is called apical dominance. Removal of the tips of the shoot normally helps in the development of the lateral buds.

Thus, the correct answer is option C i.e., Less amount of auxin in lateral buds.

Note: Any plant growth regulator has various physiological effects on plants. Plant growth regulators can behave in a synergistic or antagonistic manner. Plant growth and production can also be influenced by nutrition, light, temperature, oxygen levels, gravity and external influences.