Broad bean plant

The flowers and the bees

Farmers rely on many plants being pollinated

Since most plants are soil-bound, they don’t go around looking for mates. To reproduce, many wait for pollen to arrive on their stigma. Pollen grains, produced by the anthers, contain male reproductive cells or gametes – the equivalent of sperm in animals – that fertilise female gametes inside a plant’s ovaries. Sometimes pollen is transported by the wind, but plants have also evolved some fascinating strategies for luring in insect pollinators.

The corpse flower Amorphophallus titanium, for example, produces inflorescences, or clusters of flowers, up to a metre wide, and smells like rotting flesh, attracting beetles to pollinate it. Meanwhile, the white flowers of broad beans almost exclusively attract bees, which are heavy enough to lever down the parts of the flower that conceal the female carpel (made of the stigma, style and ovary) and male stamens.

At least a third of the world’s food crops are thought to rely on pollination by animals – including bats, birds, and insects such as bees. Many farmers are concerned about the widespread disappearance of bees: the cost of declining bee populations to the global economy, in terms of crop production, is estimated at nearly US$6 billion. Bee declines appear to have a combination of causes, including disease and certain insecticides.

Lead image:

allispossible.org.uk/Flickr CC BY NC

References

About this resource

This resource was first published in ‘Plants’ in May 2016.

Topics:
Cell biology, Ecology and environment
Issue:
Plants
Education levels:
11–14, 14–16, 16–19, Continuing professional development