FRUIT Fruit Functions Fruit mature ripened ovary 1

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 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.