Question

Which element is required for the synthesis of auxin?

• A. Cu
• B. Zn
• C. Mo
• D. Mn

Answer 1

The correct option is B Zn

Plants obtain zinc as ${\mathrm{Zn}}^{2^{+}}$ ions. It is essential for auxin biosynthesis and also activates various enzymes, especially carboxylases.
Copper plays a role in activation of enzymes.
Mo helps in nitrogen fixation and Mn is essential for photosynthesis.