FRUIT
Fruit Functions
Fruit = mature, ripened ovary
1. Prevent the seeds from drying
2. Disperse the seeds
May be either fleshy or dry.
Fleshy Fruits
• Examples: tomatoes and apples
• Hold juices that prevent the seeds from
drying until they are mature
• Easy to disperse seeds via dissemination
from feces of animals who ate the
fruit/seeds
• THREE fleshy fruit types: simple,
aggregate, multiple
Simple fruits develop from a
single ovary of a single pistil.
5 SIMPLE FLESHY Fruit Categories
Berry = entirely fleshy ovary, examples:
tomatoes, dates, blueberries, bananas, peppers,
cranberries
Hesperidium = leathery rind, examples: oranges,
grapefruits, lemons, limes
Pepo = hard rind and a fleshy inner matrix,
examples: watermelons, cantaloupe, squash,
pumpkins
Drupe = fleshy exterior and single hard, stony pit
surrounding the seed, examples: cherries,
peaches, olives, plums
Pomes = fleshy exterior and a center with papery
carpels, examples: apples and pears
Aggregate/Multiple FLESHY Fruits
Aggregate fruits develop from a single flower
that has many pistils. Multiple, fleshy fruitlets are
attached to one receptacle.
-Raspberries are an aggregate of drupes.
-Strawberries are an aggregate of achenes.
Multiple fruits consist of a number of flowers
that fused to form a mass
-Pineapples
Simple fruits develop from a
single ovary of a single pistil.
DRY FRUITS
Dry but still prevent seed
from drying further
Other means of dissemination than
consumption/defecation
- Example: dandelion has evolved a
dry, feathery fruit to take advantage of
the wind for dissemination
TWO types = indehiscent or dehiscent
Indehiscent DRY Simple Fruits
Indehiscent fruits = do not split open at maturity,
usually one- or two-seeded
Achene single-seeded fruit attached at only one place
to the pericarp, ex: sunflowers, buckwheat
Caryopsis achene like but pericarp sticks to the seed,
ex: corn, rice, barley, rye, sorghum, oat, wheat
Samara usually single-seeded with a membranous
wing, ex: maple, elm, and ash
Nut hard, one-seeded fruit, ex: oak, walnut, filbert
Uricle like an achene, but the ovary wall fits loosely
around the seed, ex: finger millet and pigweed
Nutlet is a small version of a nut, ex: birch
Dehiscent DRY Simple Fruits
Dehiscent fruits = fruits that split open
upon maturation
Legume = pod ex: soybeans, green beans,
peas
Follicle = single carpel that splits, ex:
milkweed
Capsule = more than one carpel, united and
form many-seeded fruits, ex: okra, cotton,
mustard
Pyxis capsule with a lid that falls from the
fruit, ex: purslane
DRY Fruits
3 Parts of the Fruit
1. Exocarp = outer wall of the fruit, forms
tough outer skin
- Can be thick/tough (oranges) or thin/soft
(grapes)
2. Mesocarp = middle layer, makes up the bulk
of the fruit and is usually fleshy
3. Endocarp = inner part, surrounds seed(s)
- Can be hard (peach) or soft (grapes)
How are seedless fruits produced?
A. Parthenocarpy, fruit may develop without
fertilization. Seedless pineapples and
cucumbers result when pollination fails to
occur.
1. Pineapples are self-infertile. In other words,
pineapples require cross-pollination for seeds to set.
2. Cross-pollination does not occur when a field is
planted with just one variety. Many citrus fruits are
seedless for the same reason.
3. Cucumbers may produce seedless fruits if not
pollinated. If pollination takes place, they produce
seeds.
Seedless fruits (cont.)
B. Stenospermocarpy
Technically, seedless grapes are not
seedless. Normal pollination and
fertilization occurs, but the embryos
abort when they are young. Often,
remnants of the seeds can be seen in the
fruit.
Seedless fruits (cont.)
C. Triploid
• Bananas and seedless watermelons
• Have three sets of chromosomes so
meiosis fails to take place.
– The triploid banana varieties are propagated
asexually by removing and planting offshoots.
– Watermelons are produced from seeds
obtained by crossing diploid plants with
tetraploid plants. The seeds from the cross are
triploid. The triploid plants grow and produce
fruit after being pollinated, but because they
are sterile, they fail to produce seeds. Triploid
plants must be grown near pollen-producing
diploid plants.