Why do hibiscus have red colour and sunflowers have yellow colour?
The red colour of hibiscus and the yellow colour of sunflower are due to the pigments called anthocyanins and xanthophylls, respectively, which absorb certain wavelengths of light and reflect others.
Anthocyanins in Hibiscus
Anthocyanins are a group of pigments responsible for the red, purple, and blue colours in plants. They are water-soluble pigments that belong to the flavonoid group. In hibiscus flowers, the anthocyanins absorb light in the blue and green wavelengths, which causes us to see the red colour of the petals. This absorption of specific wavelengths of light leads to the reflection of red light, giving the hibiscus its vibrant colour.
Anthocyanins are known for their antioxidant properties and are believed to play a role in protecting plants from environmental stressors like UV radiation and pathogens. In addition to their visual appeal, the red colour of hibiscus flowers also serves as a signal to pollinators, attracting bees and other insects for pollination.
Xanthophylls in Sunflowers
Xanthophylls are another group of pigments found in plants, responsible for producing yellow colours. These pigments are part of the carotenoid family and are lipophilic, meaning they are soluble in fats and oils. In sunflowers, the xanthophylls present in the petals absorb light from the blue end of the spectrum, leading to the reflection of yellow light that we perceive.
Xanthophylls are not just aesthetically pleasing; they also have important physiological functions in plants. These pigments play a role in light-harvesting processes during photosynthesis and act as antioxidants, protecting plant cells from oxidative damage. Sunflowers utilize the yellow colour of their petals to attract pollinators like bees and butterflies, aiding in the reproductive success of the plant.
In conclusion, the red colour of hibiscus and the yellow colour of sunflower are the result of specific pigments, anthocyanins and xanthophylls, respectively, that absorb certain wavelengths of light and reflect others, creating the beautiful hues we see in these flowers.