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Film info
Film summary
Different species of parasitic plants steal nutrients from host species in order to survive. Sometimes this ends in the death of the host.Key facts
- Parasitic plants derive some or all of their nutrients from other plants
- Some plants latch on and stay in balance with their hosts
- Some are out to kill their hosts.
- Examples include mistletoe, the dodder vine and the strangler fig.
Transcript
Parasites
Some plants spend their lives stealing from other plants and are known as parasites.
Parasites are organisms that derive some or all of their nutrients from other organisms, in a way that is not mutually beneficial.
Mistletoe is a parasitic plant; it can only exist by growing on another tree, as it has no roots.
Mistletoe:
Found in North America and Europe
Mistletoe grows on branches of host trees, tapping into the plant's transport system to steal water and sugary sap.
Most mistletoe species have green leaves, enabling them to manufacture some food by photosynthesis but many parasitic plants can't even manage that.
This dodder vine is germinating.
A totally parasitic plant, its seeds must quickly find a host or they will die.
Dodder vine:
Found worldwide
Temperate and tropical climates
Not even a nettle sting will deter the dodder.
The seedlings suck the sap from the nettle's stem, fuelling the dodder's growth, and when it has enough nourishment it will flower.
A single dodder seedling may, in time, overwhelm a whole bed of nettles.
The mistletoe and dodder vine rely on their host staying alive but one plant sets out to kill its victim.
A young fig tree grows slowly on the branch of its host.
Its roots crawl over the branches and some head for the ground.
Supplied with nutrients it now grows extremely quickly, its rootlets wrapping around the hosts trunk forming a web.
The host tree is being killed – this is a strangler fig.
Strangler fig:
Found in tropical forests
Over several years, the fig roots will strangle the trunk, stealing most of the nutrients from the soil and blocking sunlight from reaching the host's leaves.
The host tree will eventually die.
As its trunk rots away, the fig remains standing as its roots have formed a hollow cylinder strong enough to support it.
The plant world is filled with parasitic plants, some just looking for an easy ride, but others are out to kill.
