Heliotropism

Heliotropism refers to the phenomenon exhibited by certain plants, whereby they orient or move in response to the direction of sunlight.

Types of Heliotropism

There are two main types of heliotropism:

1. Positive Heliotropism: This occurs when plants turn towards the source of sunlight and follow its movement throughout the day.
2. Negative Heliotropism: In contrast, negative heliotropism is observed when plants move away from direct sunlight and position themselves in shaded areas.

Mechanism of Heliotropism

Heliotropism is mainly regulated by plant hormones, such as auxin, which influence the growth and bending of plant tissues. The movement of plants is a result of differential growth rates in specific regions of the stems or petioles, causing them to bend towards or away from the light source.

Significance of Heliotropism

Heliotropism plays a crucial role in maximizing a plant’s exposure to sunlight, which is vital for photosynthesis. By following the sun’s path, leaves can optimize their light absorption, resulting in increased production of sugars and energy synthesis. Additionally, it helps in avoiding excessive exposure to sunlight that can lead to damage or dehydration.