A study case on coffee (Coffea arabica): Limu Coffe - IRD

Flowers are white and generally pentamerous. The flower buds are produced at the
leaf axils of mature green wood. Temperature and drought bring buds into dormancy. After
several weeks of water stress, rain induces flower growth followed by opening within eight to
ten days. Fertilization takes place after pollination where the fusion of one male nucleus and
the polar nuclei forms endosperm. It is this endosperm that forms the coffee bean.
Illustration 2: Coffee flower (Bossolasco, 10 th
October 2009)
The fruit of the coffee tree is a drupe which normally contains two seeds; these ones
are flat on one side. When a single seed develops, its shape is oval and gets called peaberry.
Fruit is commonly referred to as cherry when ripe, and as berry when unripe. Five periods can
be distinguished during the growth of the berry: pinhead, rapid fruit growth, endosperm
growth, endosperm hardening, and fruit ripening. The whole takes seven to eleven months
(the most of it eight to ten months). The coffee fruit is oval. When unripe the colour is green,
and when ripe the skin is red (yellow for some varieties). The seed is covered with a thin
membrane (silver skin). Above the silver skin is the parchment. A coating of slimy mucilage
covers the parchment. The fleshy outer covering comprises the pulp and skin.
Illustration 3: Coffee red cherries, pulp, and beans covered by their sticky mucilage
(Bossolasco, 1 st July 2009)
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