Natures wonders: venus fly trap specifics (Introduction)

by David Turell , Monday, April 24, 2017, 00:18 (2769 days ago) @ David Turell

The Venus fly trap digests insects. Here is a fairly complete description:

https://www.sciencedaily.com/releases/2017/04/170421103741.htm

"When a prey tries to escape the closed trap, it will inevitably touch the sensory hairs inside. Any mechanical contact with the hairs triggers an electrical signal that spreads across the trap in waves. From the third signal, the plant produces the hormone jasmonate; after the fifth signal, the digestive glands that line the inside of the traps like turf are activated.

"What happens next in the gland cells? They increasingly produce membranous bubbles filled with liquid (secretory vesicles) and give off their content. This happens after mechanical stimulation of the sensory hairs but also when the glands come into contact with the hormone jasmonate. The entire process depends on calcium and is controlled by a number of specific proteins.

"Moreover, genes are activated in the glands: "We assume that they provide for the vesicles being loaded with protons and chloride, that is hydrochloric acid," Hedrich explains

***

"Should the vesicles contain hydrochloric acid in the first hours after catching the prey but no digestive enzymes yet? And no molecules yet that assure the enzymes' functioning in the acidic environment? Does the plant have to produce all this first?

"That's exactly how it works: Molecular biologist Ines Fuchs found out that the plant only starts to produce the enzymes that decompose the prey after several hours. The first characteristic signals occurred after six hours and the process was in full swing 24 hours later. During this phase, the trap is completely acidic and rich in digestive enzymes.

"Professor Heinz Rennenberg (Freiburg) also found glutathione (GSH) in the secreted enzyme. This molecule keeps the enzymes functional in the acidic environment of the Venus flytrap.

"The same processes as described above take place in the same chronological order both when the sensory hairs are stimulated and when exposing the trap to the hormone jasmonate only. "A touch will very quickly trigger the jasmonate signalling pathway, but it takes time until the vesicles are produced and loaded with the proper freight which is facilitated by the hormone," Hedrich explains.

***

"His experiments also showed that when the influx of calcium into the glands is blocked, the trap remains dry. "The calcium activation of the gland cells is therefore crucial," Hedrich says. "So we will now take a closer look at the biology of the calcium channels of Venus flytrap. "

Comment: Humans also use hydrochloric acid in their stomach for digestion. It seems evolution develops the same pattern here. The big question both for the plant and for humans is how did the digestive mechanism develop with protection built in for the digestive pouch. Both the acid and the protection had to develop at the same time. Only simultaneous development by saltation is reasonable. The plant did not develop this bit by bit, per Darwin.