VIP: Fruit Development

Plant hormones influence the early development of an ovule as it becomes a seed and of a carpel as it becomes a fruit...

Early in development the ovule produces the hormone CK which causes the cells of the carpel to divide and increase in number.
Later, the ovule produces the hormone GA which causes the cells of the carpel to expand to achieve full fruit size.
Finally, the "mother" plant produces the hormone AbA which causes the embryo to go dormant inside the ovule that has become a seed.

Now that the fruit has grown to full size, we can now classify it. Indeed the classification of fruits can assist us in the identification of plant species.

Three Fruit Classification Schemes

Origin flowers pistils fruits examples
Simple 1 1 1 grape, cherry, tomato, bean
Aggregate 1 ∞ ∞ strawberry, raspberry
Multiple ∞ ∞ (1 each) fused into one body mulberry, pineapple

Composition flower parts involved examples
True ovary wall only cherry, tomato
Accessory receptacle ± sepals, etc. apple, blueberry

Description name feature examples
fleshy drupe stony pit cherry, peach, almond, walnut
berry seeds in flesh grape, tomato, orange, banana
pome cartilaginous core apple, pear, quince
dry dehiscent follicle splits one side milkweed, magnolia
legume splits two sides pea, bean, peanut
capsule multiple openings poppy, hibiscus
dry indehiscent achene one free seed daisy, sunflower, strawberry
caryopsis seed coat & fruit wall fused corn, wheat, rice, barley
nut leathery in involucre acorn, chestnut, filbert

Note: any one fruit can be classified in each of the three schemes. Try to classify some common fruits at the supermarket, in a salad bar, in your refrigerator, or in the cafeteria using all three schemes for each fruit.

This page © Ross E. Koning 1994.

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