SYMBIOSIS comes in many flavours. Lots of animals trade protection or food in a mutually beneficial relationship. Now there is a flower that offers yeast its sugary nectar in exchange for warmth.
A European herb, the stinking hellebore, is the only plant discovered so far that relies on another organism to generate heat for it. Other plants, like the famous 鈥渃orpse flower鈥� whose blooms smell of rotting flesh, warm up by breaking down salicylic acid, or by tracking the sun鈥檚 movement.
鈥淭he stinking hellebore is the only plant discovered so far that relies on another organism for heat鈥�
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Yeasts are common in a wide range of flower nectars, says of the Do帽ana Biological Station in Seville, Spain. It is deposited there by pollinating bumblebees, who pick it up from other flowers. Herrera and his colleagues took a sample of yeast from a local bumblebee in the Spanish mountains of Sierra de Cazorla. They injected the yeast into 37 鈥渧irginal鈥� specimens of Helleborus foetidus, which had been covered in netting to keep pollinators away.
The team then compared the temperature of these flowers to the temperature of flowers with yeast-free nectaries. Flowers with yeasty nectar turned out to be 2 掳C warmer on average, and up to 7 掳C warmer when yeast densities were high. ().
It鈥檚 a significant spike in temperature for the plant, says Herrera. 鈥淏ut unless you have ultrasensitive fingertips, you won鈥檛 notice it by touch.鈥� The yeast generates heat when it breaks down nectar sugars to grow.
What is in it for the plant? 鈥淭he temperature rise may cause the flower to release a volatile which attracts more pollinators to the flower,鈥� says of the department of plant sciences at the University of Oxford. That is certainly what happens in another hot flower. The voodoo lily, a cousin of the corpse flower, has a temperature spike the day it blooms. As with the corpse flower, 鈥渢his releases putrid amines, which smell like dead carcasses and attract pollinators to the flower, boosting its reproductive success鈥�, says Gurr.
