What is the principal hormone that causes phototropism in stems or leaves?
A)auxin
B)gibberellin
C)abscisic acid
D)ethylene
E)cytokinin

Question

Quizplus · Accepted Answer

The principal hormone that causes phototropism in stems or leaves is auxin. Auxin is produced in the apical meristem and moves down the stem or towards the shaded side of the plant, causing elongation of the cells on the shaded side and bending of the stem or leaves towards the light source.

What Is the Principal Hormone That Causes Phototropism in Stems