The process enhances photosynthesis, increases plant growth, and attracts more pollinators. Thus, helping in the overall development of the plant. Examples of heliotropic plants include sunflower, beans, alfalfa, arctic poppies, and buttercups. In 1832, the Swiss botanist A. P. de Candolle first introduced the term heliotropism, derived from the Greek ‘helios’, meaning sun.
Its Types
How It Works
Heliotropism vs. Phototropism
This rapid readjustment of leaves throughout the day is controlled by a specialized organ called the pulvinus. It is a fluid-controlled joint found in the petiole, the base of a leaf. Advantage The leaves orient horizontally in the morning and afternoon to capture the maximum sunlight. On the contrary, when the sun is most intense in midday, the leaves orient parallelly to avoid overheating and dehydration.
In Flowers
Some flowers slowly track the sun’s path across the sky from dawn to dusk. The sunflower is considered the most common example of a heliotropic flower. However, it only tracks the sun in its early developmental stage or the bud stage. Many tropical flowers exhibit a modified form of heliotropism where they move opposite to the sun’s direction to reduce the chance of overheating (negative heliotropism). Advantage As the flowers face the sun, their temperature rises. This added warmth attracts more pollinators, enhancing fertilization and seed development.
