Kristi Sootla - How Does the Colour of a Blossom Impact Bolting?
Plants don’t have pretty blossoms just for the benefit of people. Their purpose is to attract pollinators. Kristi Sootla, a PhD student of analytical biochemistry at Tallinn University explains how this process works.
Plants don’t have pretty blossoms just for the benefit of people. Their purpose is to attract pollinators. Kristi Sootla, a PhD student of analytical biochemistry at Tallinn University explains how this process works.
The relationship can be fair – the pollinator receives nectar, dust, a hiding place, or some other benefits. It can also be unfair: the deceiving plant could be imitating a beneficial blossom, or a female specimen of the pollinator’s species. The latter can is considered sexual deceipt.
Every type and colour of blossoms has coevolved with a certain pollinator. Thus, bees visit yellow or blue blossoms, butterflies fancy pink or purple blossoms, and moths prefer white blossoms with strong smells.
Hummingbirds help pollinate blossoms that are red and have no scent. To make things more complicated, there are also various lighter colours that lack pigments, such as white or green blossoms.
The question arises: what is their purpose?
Any genetic variety is vital for the survival of a species. When conditions change, so must the living organisms.
This is why in polluted areas only butterflies with darker wings survive. With plants we may presuppose that as daytime pollinators become extinct, the flowers with white blossoms that are pollinated by moths will be more successful.
When a bug fails to find nectar from a deceiving species, it will fly as far as possible and to a completely different sort of blossom. This way it will help cross two different plants, ensuring genetic variability.
Our most common orchid, the fragrant orchid (Gymnadenia conopsea) has various mutations, from the more common violet blossoms to light pink and white blossoms.
The bolting of orchids with white blossoms is much weaker than that of pink blossoms, which are still not as successful as the typical violet ones.
In her doctoral thesis “The factors concerning the bolting of the fragrant orchid”, Kristi Sootla looks at the reasons behind the mutations, including the chemical structures of the fragrances and the nectar.
The pigments that determine the colour of blossoms are linked to the substances that attract pollinators and detract bugs that eat plants. These substances may be less influential in plants with white blossoms, making them less attractive to pollinators. A comparative research using 1028 plants proves that there are differences in the bolting of plants with different colours of blossoms.