How Do Plants Know When To Shed Their Leaves?
Winters in the US Northeast are brutal. In my house, we run
through sort of a mental checklist in preparation for the winter. Do we need
new winter jackets? Are there any leaks in the windows that have to be sealed?
Is the home’s heating unit in good condition?
On the other hand, trees have no such luxury and are forced
to endure the harsh winter, year after year. An important defense mechanism that
trees use is to shed their leaves and sealing the pores, so they do not freeze
to death.
But how do plants know when to shed their leaves? If they
shed too early, they will miss out on photosynthesis but if they wait too long,
they might freeze to death. On top of that, not all winters are exactly alike.
Some years, there are snowstorms in late fall, and in other years, there’s only
a total of a few inches of snow by late January. It is very unpredictable.
As it turns out, trees do not take their cue from the
changing temperature. They use the gradual shortening of the days as the cue to
start preparing for the winter. Changes in the light patterns are more
consistent than weather pattern. In other words, trees trust the Sun to tell them
when winter is coming!
Reference:
In a dense forest, the trees and plants in the bottom never get sunlight and are always dark. How do they know? ..
ReplyDelete