Awns…

 
…are the long "bristlelike" projections
on the seeds of wheat, oats and grasses.

They play a role in the dispersal
of seeds in the air and the actual
planting of them in the ground!

Wheat FEEL

The awns feel the changes in humidity
and this leads to their bending.
This bending helps them push
the seed along. By bending back
and forth upon feeling these
slight changes in humidity
they accomplish the digging,
the pushing and then in
the final burial of the seed down
a few inches into the soil!
• • • • • • • • • • • • • • • • •

 • 10" x 10" • Lisa Rivas © 2007 • "Feeling"
• watercolor, digital, printed on ricepaper and mounted on canvas

The great art of life is sensation, to feel that we exist, even in pain. Lord Byron

What a country calls its vital economic interests are not the things which enable its citizens to live, but the things which enable it to make war. Petrol is more likely than wheat to be a cause of international conflict. Simone Weil

The Role of Wheat Awns

One cycle in the humidity-driven movement of the awns.
(I) shows the seeds and part of the awns immersed in soil. The red arrow indicates one of the silica hairs.
(II)
Because of increased humidity, the awns straighten. The silica hairs
lock the awn and prevent an upward movement. As a consequence, the seed
has to move downward by a distance d, indicated in (I), to account for
the increased length projected onto the vertical.
(III) After
drying, the awns bend again, which shortens the length projected onto
the vertical. Because the silica hairs are locked into place, the seed
cannot move back upward, and the awns are drawn further down into the
soil

https://www.sciencemag.org