In the spirt of fall

The time for trick-or-treaters has recently past and as ghosts and goblins are transformed to Frosty the Snowman and tree-topping angels, green grasses are shaded with fallen leaves.

But exactly why do fall leaves tumble to aide in hours of pile-jumping?

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A common misconception lies within the name of the season; fall!  A breeze sweeps through the trees and wiggles loose leaves that have been dried by the cold.

According to a report by National Public Radio, the tree itself is in fact responsible for the dropping of the leaves.  They shed their leaves by using their own personal “scissors”.

Around this time of the year, the drop in temperature triggers a change in hormones in certain trees that are accustomed to dropping their leaves.  The hormone sends a chemical message to the leaf telling it that it’s time to fall.

According to Peter Raven, president of the Missouri Botanical Garden and a renowned botanist, once the message is received, abscission cells appear at the place where the leave stem meets the branch.  Within a few weeks, or days, a line of cells push the leaf from the branch and send it falling to cover the ground beneath it.

cells University of Wisconsin Plant Image Teaching Collection

The “scissor” cells are stained red.

In the spirit of Halloween, doesn’t it make you think; if trees have a mind of their own, what else does?

image-5DC6_49600055Optical Illusions

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~ by awhite2 on November 3, 2009.

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