Page 137 - Photosynthesis: The Green Miracle

Bud in the
space between
leaf stalk and
branch

Leaf
stalk
Separation layer
Fungus cells in
the protective
layer

Leaf shedding results from exceptionally complex events that occur between every leaf
stem and the branch. Such shedding might appear fairly unremarkable to people without
much knowledge of the subject. The fact that the same process takes place flawlessly
every autumn, and has been going on for millions of years, may induce a feeling of fa-
miliarity. Yet before leaves fall, a series of highly complex chemical processes takes
place. Thanks to this, a plant’s nutrients are not lost along with the leaf.

body only by vessels that permit only fluids to pass through. Very rapid
changes take place around the fissure as it continues to widen, and the
cells begin to produce some kind of fungus essence. This substance grad-
ually places itself in the cellulose in the membrane and stiffens it. All the
cells producing fungus essence die, leaving a large empty space behind
them. As a result, the leaf breaks off in a light breeze. However, at this

point a layer of fungus develops to cover the leaf scar that has opened.
These physical and chemical changes are a very carefully planned process
that takes place not just in one leaf but in all of them. This system has been
created to ensure that leaves fall off when the proper time comes.

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