Monday, May 01, 2006
Now Why Is That...?
This is puffball, one of the sensitive briars...not sure which one exactly and not anguishing about it. This one grows along the ground, amongst the grass in thick carpets of green and pink. The point of this post is the behavior of this plant and not it's fancy shmancy taxonomic name.
If you touch the leaves of this plant, they fold up immediately.
We could spend time wondering about how they know they've been touched, since plants don't have nerves...but that kind of thinking makes my head hurt...it's too soon after Grad Bash.
I prefer to wonder about the reason for this behavior. I am fond of telling my charges that every adaptation, whether structural or behavioral is a survival tactic. In effect, behaviors and physical structures aren't "just there", rather, they are only there because they offer improved chances for survival.
So I wonder about this behavioral adaptation of the puffball. If I squint, I can sort of picture the mechanics involved...it seems reasonable that a sudden drop in turgor pressure could cause a quick wilt. I picture the plant emptying water vacuoles suddenly causing the leaves to fold up from loss of turgor. (I'm not saying that's how it happens, botanists, I'm just thinking out loud)
I am more intrigued by the possible reasons for such a behavior.
Could it be that closing your leaves when some herbivore touches you discourages the leaf muncher ? Is the plant hiding?
Could it be a way of kicking caterpillars off your leaves...as if someone pulled the rug out from under you?
I'm sure it's not happening...JUST BECAUSE.
There has to be a good survival reason for it.
What do you think?
(This is not a puzzler...except to me. Don't expect an answer from yours truly)
Posted by R.Powers at 5:45 AM