(1) Sulphur - Stabilization of protein structure
(2) Manganese - Expression of apical dominance
(3) Zinc - Activation of IAA oxidase
(4) Potassium - Maintenance of anion cation balance in cells
$\begin {array} {1 1} (1)\;(II),(III) & \quad (2)\;(II),(IV) \\ (3)\;(I),(IV) & \quad (4)\;(I),(II) \end {array}$
