This may sound stupid, but do plants have nervous systems, or anything analogous?

Question

(And by analogous, I mean something that serves the function of nerves, even if it isn't a nerve by the animal deffinition.) Someone answering a question on vegetarianism in another category claimed that they did.

While I know that plants are capable of responding to their environments, this person's claim seems a bit far-fetched. Nevertheless, how exactly do plants respond to external stimuli? How does a phototrophic plant know to bend its whole self towards the sun? How does a venus flytrap know to close its "mouth" when only part of that mouth is stimulated? Are there any other such responses that plants can have, and if so how do they work? I know there is a logical explaination.

I know, big question, tall order. So, any sources I could study, preferebly of the only (easily accessable) sort would be most appreciated. Thanks and God bless!

Answer 1

Plants have nothing analagous to a nervous system.

The behaviors of plants that you notice are not the result of a nervous system - they're just local responses to stimuli.

For example, plants don't actually know to bend themselves towards the light. Instead, the rate at which the cells in the stem reproduce (or grow; can't remember which) is determined by how much sunlight they get. Cells that are in the dark most of the time reproduce more quickly - the result is that the plant, as a whole, bends towards the light.

I don't remember why the venus fly trap does what it does, but i do know that it has nothing to do with nervous systems or anything analagous to them. Wikipedia has a good explanation:
http://en.wikipedia.org/wiki/Venus_fly_trap#Mechanism_of_trapping

Here's the wikipedia page about plants that move fast:
http://en.wikipedia.org/wiki/Rapid_plant_movement

Answer 2

They don't have a nervous system but they have hundreds if not thousands of analogous mechanisms to react to stimuli and then transmit those signals to other parts of the plant. You brought up two excellent examples.
I imagine that the vegetarian question/answer might have been trying to equate these analogous mechanisms to the fact that plants might feel pain or suffer from the trouncing we give them. That would be more of a question of our anthropomorphic interpretation of many things in nature, which I think is just a bunch of hogwash.

Answer 3

Dear friend,
Plants do not have anything like nervous system generally as we animals have.
though they produce hormones that make them response to the external environment. Like auxin make themmove and grow towards light.

Answer 4

No nervous systems in plants, but a lot of reactions due to environmental stress (e.g. tropism).
Please have a look to refs above.

Good luck.