DEVELOPMENT OF THE GRAIN
THE FOLLOWING PICTURES SHOW THE DEVELOPMENTAL
STAGES OF THE GRAIN. THE GRAIN DEVELOPS FROM THE POLLINATED OVARY IN THE
COURSE OF A FEW WEEKS. AS LONG AS THE WOULD-BE ENDOSPERM IS LIQUID, THE
GRAINS ARE SAID TO BE IN THE MILKY STAGE OF RIPENING. AS SOON AS THE COLOR
OF THE GLUMES CHANGES TO A YELLOWISH OR BROWN HUE AND THE ENDOSPERM BECOME
SOLID ( IT MUST BE HARD ENOUGH TO BRAK OVET THE THUMB-NAIL AND NOT ONLY
COLLAPSE ), HARVESTING MAY BE STARTED. THIS STAGE IS CALLED YELLOW RIPENESS.
ABOVE YOU CAN STILL SEE THE STAMENS EMERGING WHICH
TELLS YOU
THAT THESE ARE STILL FLOWERS. THEY ARE
VERY FLAT AND OBVIOUSLY
CONTAIN NO FRUIT INSIDE.
IN THIS PHOTOGRAPH YOU CAN SEE THAT THE SPIKELETS
APPEAR MUCH
THICKER AND ARE BEGINNING TO CHANGE COLOR.
SOME OF THEM HAVE
BECOME COMPLETELY GOLDEN, AND THE ONES WHICH
ARE STILL GREEN
MAY BE IN THE MILKY STAGE OF RIPENING.
THESE ARE FULLY DEVELOPED GRAINS. AS YOU CAN SEE THEY
HAVE
BECOME VERY BULKY AND FULL ; READY FOR HARVEST.
THIS IS THE
YELLOW RIPENESS STAGE.
HERE SOME OF THE GRAINS ARE BEGINNING TO DARKEN BEYOND
THE GOLDEN YELLOW COLOR.
AT THIS POINT THE GRAINS HAVE TURNED ALMOST
COMPLETELY
BLACK . THIS INDICATES THAT THE RIPENING
PROCESS WAS ALLOWED
TO GO ON FOR TOO LONG AND THEY CAN NO LONGER
BE HARVESTED.
I SUPPOSE YOU COULD SAY THAT THE GRAIN HAS BECOME
ROTTEN.
Introduction | Flowers&Fruit
| Roots | Stems
| Leaves
© Thomas L. Rost 1997
Section of Plant Biology
Division of Biological Sciences
UNIVERSITY OF CALIFORNIA, DAVIS