Natures wonders: venus fly trap (Introduction)

by David Turell , Wednesday, December 27, 2017, 15:37 (2521 days ago) @ David Turell

A most unusual plant:

https://cosmosmagazine.com/biology/the-secret-life-of-the-venus-flytrap

"The world’s most famous carnivorous plant can eat frogs and count.

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"The Venus flytrap and the waterwheel plant are the only members of their respective genera, and they alone have ended up with a lightning-fast ‘snap-trap’ mode of capturing their prey.

"While carnivory in plants has evolved at least six times independently, it’s thought that snap-traps evolved only once, in the common ancestor of Aldrovanda and Dionaea.

"Late last year, Shabala and an international team of researchers discovered that this ‘snap-trap’ method of catching prey is based on the Venus flytrap’s ability to count: one means ignore, two means prey.

“'They don’t really recognise animals, they respond to mechanical stimulation,” Shabala explains.

“'When the animals walk across the plant, it produces a force, and if there are two touches within five seconds, it closes. One is not enough, because it could be a false start, but two means there’s something there.”

"Once the prey has ventured into the Venus flytrap’s jaws – often lured in by the sweet scent of the plant’s nectar – the flytrap gets ready to snap shut.

"Venus flytraps are equipped with sensory trichomes, which are external, hair-like structures that sit on its surface to pick up signals from wandering prey.

"These trichomes work like a booby-trap: they’re connected to an on channel that’s triggered by touch or pressure.

“'Usually it will close by 90 to 95%, but if the animal keeps struggling, it will send additional signals, and close completely,” says Shabala.

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"After sealing an insect inside the snap-trap, the plant will emit digestive enzymes from specialised glands to dissolve its tough outer exoskeleton.

"Once the Venus flytrap has broken through that layer, it will start processing the insect’s nitrogen-rich blood.

"And in case you’re wondering, yes, those enzymes can break down human flesh, according to Barry Rice from the International Carnivorous Plant Society, who put a slice of his own freshly shed skin into a Venus flytrap.

“'After a week, the traps opened. I had predicted the skin chunks would be relatively inert and unaffected … [but they] were almost completely digested. Worse, what was left no longer had much cohesion, but was gooey and slimy.”

"One challenge carnivorous plants face is the fact that their food is far saltier than what most plants are used to, so they’ve had to evolve ways of ridding their cells of the excess sodium.

"In a 2016 study, Shabala and his team figured out how they do this, and are now working on ways to imbue crops with this trait so they can withstand saline environments.

"When they examined the movement of salt from the prey to the Venus flytrap’s ‘stomach’, they found that specialised sodium transporters got rid of the excess by depositing it into ‘capture organs’ so it wouldn’t interfere with the plant’s metabolism."

Comment: The biggest issue in understanding its evolution is how did it develop self-protection against digesting itself while developing digestive enzymes for it prey? Both had to happen simultaneously. And then they had to handle the salt overload. Is it designed?