Why About Everything?

Why do Bananas, unlike other fruits, grow upward?

The banana is actually a giant herb in the same biological family as lilies, orchids and palms. It is the largest plant on earth without a woody stem- a banana stalk is 93 percent water-and is consequently extremely fragile. Although it can reach a full height of fifteen to thirty feet in one year, even moderate winds can blow down a plant.

        The fruit stem or bunch originates at ground level. At this stage, the bunch consists of all the fruit enclose in leaf bracts. The individual fruit "fingers" (the technical name for a single banana) are pointed upwards. As the bunch or bud is pushing its way through the mass of tightly packed leaf sheaths known as the pseudo-stem, the fruit fingers remain pointed upward until they emerge at the top of the plant.

           The bananas exert tremendous pressure on the pseudo-stem. Before the fruits expand, the leaves enclosing them roll around themselves inside the trunk. After the fruit emerges from the leaves, the fingers point downward, but only because the bud surrounding them has changed direction.
            Once the entire bunch of bananas is mature, fully emerged from its sheath, and pointing downward, the individual leaf bracts enclosing the hands fall away, exposing the fruit. At this point, the individual flowers grow rapidly, filling out. Their increased weight bends the main bends the main stalk so that the individual fruits on the hand start to turn upward in about seven to ten days. This phenomenon is known as "negative geotropism".