Thursday, 9 April 2009

Smelly stamens

Photo: I know it isn't a grapevine, but this Gymea Lily has lovely anthers

I was intrigued by this report through EurekAlert! It was headed 'male flower parts responsible for potent grapevine perfume' and it tells the story of a flower with smelly stamens. Botanists at University of British Columbia found that the fragrance in a Cabernet Sauvignon flower came from the pollen.

This might not sound startling but common wisdom is that the petals alone are the perfumed bits of a flower. Joerg Bohlmann, who headed up the study, said "This discovery gives us strong clues to the origin and evolution of fragrant flowers." The full study can be found in Proceedings of the National Academy of Sciences.

Perfumes are thought to have evolved in plants to attract pollinators or to repel bugs that nibble them. It's true that in most well-known flowers the petals produce the pleasant smells - think rose petals. But it turns out that very few species have been checked.

In the case of cultivated grapes, the flowers are self-pollinated, so the perfurme is probably a repellent rather than attractant. It makes sense for the flower to protect its male bits from insect attack. Bohlmann says this kind of response 'may be more prevalent than we think'.

So what does the pollen smell like? No idea. I'll have to check next time I pass by our vineyard of half a dozen Shiraz grapevines in the Royal Botanic Gardens.

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