What effect do growth hormones have on plants?

Growth hormones, also known as plant hormones or phytohormones, play a significant role in regulating various physiological processes in plants. They can influence growth rates, stress responses, and developmental patterns.

The assessment that growth hormones can cause growth abnormalities in foliage addresses one of the key aspects of hormone action in plants. While hormones are essential for normal growth and development, an imbalance—either an excess or a deficiency—can produce abnormal growth patterns. For instance, excessive growth hormone can lead to uncontrollable growth at specific sites, resulting in deformed leaves or stems. This can include issues like twisting, curling, or excessive branching, which are often identified as abnormalities.

The other provided statements regarding the effects of growth hormones lean towards positive aspects of hormone function. Enhancing crop yield through hormonal means reflects a beneficial application of these substances, while stimulating root system development and increasing pest resistance are also favorable belowground and defense mechanisms, respectively. However, the critical point is that growth hormones can lead to abnormal growth when misapplied or when they are present in uneven concentrations, producing visible abnormal foliage.