Question

To increase sugar production in sugarcanes, they are sprayed with

• A. IAA
• B. Gibberellin
• C. Ethylene
• D. Cytokinin

Answer 1

The correct option is B Gibberellin

Functions of IAA:

• Induces root formation in stem cutting.
• Induces parthenocarpy.
• Prevents leaf drop in young leaves.
• Promotes abscission of mature leaves.
• Promotes apical dominance.

Functions of cytokinin:

• Production of new leaves.
• Development of shoot buds.
• Formation of adventitious shoots.
• Promote mobilisation of nutrients.

Functions of gibberellins:

• Delays senescence.
• Stimulates stem growth.
• Improves the shapes of fruits.
• Increases the length of plant axis.

Functions of ethylene:

• Ripens fruits.
• Breaks seed dormancy.
• Initiates germination, as in peanut seeds.
• Promotes swelling of the axis.
• Helps in apical hook formation in dicot seedlings.

Role of gibberellin in stem elongation:

Carbohydrate is stored as sugar in the stems of sugarcane. Gibberellin, when sprayed on sugarcane, results in an increase in the length of the stem thus increasing the yield by as much as 20 tonnes per acre. This results in an increase in sugar content.

Final answer: c. Gibberellin.