Question

Which of the following physiological effects is caused in plants by gibberellic acid?

• A. Shortening of genetically tall plants
• B. Elongation of genetically dwarf plants
• C. Rooting in stem cuttings
• D. Yellowing of young leaves

Answer 1

The correct option is B Elongation of genetically dwarf plants

One of the most striking effects of the gibberellins is the reversal of dwarfism in many genetically dwarf plants. Rosette plant of sugar beet, when treated with $G{A}_3$, undergoes marked longitudinal growth of axis. Similarly, dwarf pea and dwarf corn attain almost normal size when treated with gibberellins. The dwarf plants have very low GA level which appears to account for the dwarfing habit. Thus, the external supply of GA to such plants causes rapid elongation.

So the correct answer is 'Elongation of genetically dwarf plants'.