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Pine Cone Wet and Dry
Name: Rena
Status: student
Grade: N/A
Location: N/A
Country: N/A
Date: N/A
Question:
I am a Literacy Teacher and read a story about a
boy and his father buying a tree to plant in their yard. They ended
up buying a pine tree. I have several pines cones and one that I
have is inside a mason jar. I asked my students how they think it
got in the jar and how can we get it out? So, I filled the jar with
water and told my students that they will observe and see what will
happen. By the end of the day it was closing up. The next day I was
able to remove it from the jar. The question we have is,"Is a pine
cone that is not attached to a tree living or dead? They we
amazed!It has movement by closing up. I have emptied the water out
of the jar and we are watching it dry up and begin opening up again.
Replies:
Rena,
Once the pine cones are dried out by the tree cutting off the water
supply to it, it is no longer alive. Pines cones develop, in most
species, over a two year period. Pine cones have a structural
mechanism at the base of each seed petal (that houses the developing
seed) that, when it dries, it automatically opens up by moving away
from the center of the cone. This opening allows for the seed to
drop (it is also dried due to lack of water) and blow away in the
wind or just drop out by gravity. After a time that has allowed for
seed dispersal, the cone will break off its attachment to the tree
and fall. As long as the pine cone is intact, it will open and
close depending upon the water it receives or loses. Place the cone
in a glass of water, it will close as it did when it was keep moist
as the seeds were developing in the first year. These first year
cones are usually green and tightly closed.
A fun, but soon to be boring, activity is to see how many times the
cone will close and open with drying and placing it into water. It
is not alive.
Steve Sample
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Update: February 2012
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