Fruit - biology.

« from a flower with several pistils.

The ovary may have a single compartment, or carpel, which houses the ovule or ovules.

Or the ovary may consist of two or morecarpels, each of which may contain one or more ovules. A drupe develops from an ovary with a single carpel and is characterized by an edible exocarp and mesocarp and an inedible, hard endocarp, or pit that encloses asingle seed.

Cherries, peaches, apricots, and plums are examples of drupes.

Almonds also are classified as drupes, but in almonds, the fleshy exocarp and mesocarpwither at maturity, and the endocarp, or shell, is cracked to obtain the edible, meaty, seed.

Coconuts are drupes with a very fibrous, inedible exocarp and mesocarp.They are unusual in that they contain both a liquid and solid endosperm.

The watery fluid often referred to as coconut milk is used as a drink, and the solid endosperm,or whitish coconut meat, is an important food in the tropics. A berry develops from an ovary containing one or more carpels.

Each carpel contains one or more ovules, so berries typically contain more than one seed.

Examplesinclude grapes and gooseberries.

A tomato also is classified as a berry.

Cut in half, a tomato displays distinct sections, each representing a separate carpel with manyseeds. There are several different types of berries.

A true berry has a relatively soft pericarp with a thin exocarp or skin.

Examples of true berries include the tomato, pepper,eggplant, grape, and persimmon.

A pepo is a berry with a comparatively thick exocarp, or rind—cantaloupe, watermelon, pumpkin, cucumber, and squash are pepos.

Ahesperidium is a berry with a leathery skin containing oils.

All citrus fruits, including oranges, lemons, and grapefruits, are hesperidiums.

Some fruits with the wordberry in their names, such as raspberry and strawberry, develop differently and are not really berries at all. Most fruits consist of just the mature ovary and its seeds, but in some fruits other flower structures are also part of the fruit.

A pome is a fleshy fruit composed of themature ovary along with other flower parts.

These flower parts can include the petals, the colorful leaflike parts of the flower; the sepals, the small, green leaflikestructures at the base of the petals; and the receptacle, the enlarged tip of the flower stem to which the flower is attached.

Depending on the species, some or all ofthese flower parts grow and expand around the ovary forming a pome.

Apples, pears, and quinces are pomes.

An apple cut in half shows the enlarged, whitish, edibleparts of the sepals and petals. In flowers with more than one pistil, the pistils are adjacent and the ovary of each pistil develops into a tiny fruit, or fruitlet.

The clumped fruitlets form a fruit, such as araspberry, called an aggregate fruit.

Each little bump on a raspberry represents the ripened ovary from one pistil. In plants such as the pineapple, several flowers are clustered on one stem.

Although the ovaries develop individually, all the fruitlets combine into a single larger fruitcalled a multiple fruit.

Other multiple fruits include mulberries and Osage oranges. B Dry Fruits Dry fruits are classified by whether they remain intact at maturity or open to release seeds.

There are several types of intact, dry fruits.

In samaras, the pericarp islight, relatively thin, and partly or completely fused to the seeds.

It enlarges slightly, forming one or two small wings that aid in wind dispersal.

Maples, ashes, and elmsproduce beautiful samaras that can be seen twirling slowly in gusts of wind.

Nuts, on the other hand, have a relatively hard, heavy pericarp.

Examples includechestnuts, hazelnuts, and acorns.

In achenes, the seed is loosely attached to the pericarp, and the pericarp can be separated from the seed, as in sunflowers.Buckwheat and buttercups also produce achenes.

A caryopsis, or grain, is a fruit in which the pericarp is tightly fused to the seed.

A schizocarp is a twin fruit thatseparates into two one-seeded mericarps, types of fruit that often have tiny oil tubes in their walls.

Examples include caraway and dill, whose fruits are harvested fortheir flavorful oils. Dry fruits that open at maturity fall into several categories.

Legumes, such as peas and beans, are one-chambered pods that split apart along two seams, exposing theseeds that lie within.

Siliques and silicles split along two seams but contain two chambers.

Siliques are more than three times longer than they are wide, while silicles areshorter.

Broccoli, cabbage, and wallflower produce siliques, while dollar plants and alyssum produce silicles.

A follicle, on the other hand, splits along one seam only.Milkweed, columbine, and larkspur produce follicles.

Capsules split open in several ways, often along or between three or more seams, or between the top and bottomhalves, as in primrose.

Certain poppies produce capsules with rows of pores that release seeds when the capsule is shaken by the wind. IV FRUIT AND SEED DISPERSAL Fruits enable seeds to be dispersed.

Fruits are well adapted for dispersal by several mechanisms, including wind, water, and a variety of animals.

The wings of mapleand other samaras, for example, aid in wind dispersal.

Some larger, heavier seeds are so rounded that the wind can roll them along, or they can roll down a hillside.Coconuts are carried great distances by ocean currents and germinate after they wash up on beaches.

Sedge fruits have an inflated jacket and may float down astream some distance from the parent plants. Many types of animals play a role in the dispersal of fruits and seeds.

Some fruits are covered with little hooks or sticky substances and catch in the fur or hide ofanimals such as coyotes, raccoons, and deer.

As the animal moves about, the fruits or seeds are rubbed off by branches of shrubs or trees.

Ducks may disperse fruitssticking in the mud on their feet.

Woodpeckers often drop acorns while flying.

Some birds eat fruits whose seeds stick to their beaks and then are rubbed offsomewhere else.

Seeds of other fruits pass intact through a bird's digestive tract.

Ants remove the seeds from certain fruits before the fruits drop from the plant.

Theycarry the seeds to their nests, remove and eat the appendages, and then deposit the seeds outside the nest. V NUTRITIONAL AND COMMERCIAL IMPORTANCE Many fruits taste sweet and delicious, and have the advantage of being relatively low in calories and high in nutrients.

Grains and legumes are good protein sources,and other fruits contain many important vitamins and minerals as well as the complex carbohydrates needed for a balanced diet ( see Human Nutrition).

One medium- sized tomato, for example, has only 26 calories and provides vitamin C, vitamin B, beta carotene, calcium, phosphorus, iron, sodium, potassium, and zinc.

Tomatoes andsquash contain compounds called carotenoids and flavonoids, which are thought to provide protection from cancer.

Fruits are also an excellent source of the fiberneeded for a healthy digestive system. Fruits are essential in the diet to prevent certain diseases.

Scurvy, a potentially fatal disease marked by swollen joints, inflamed gums, and weakness, results from lackof vitamin C, the vitamin found in particularly high concentrations in oranges, lemons, and limes.

Unprocessed grains and legumes, along with other foods, supplythiamine, or vitamin B 1, which prevents beriberi, a potentially fatal disease of the nervous system.

Many fruits are also rich in vitamin A, which prevents night blindness, supports the immune system, helps bones grow, keeps skin healthy, and plays many other indispensable roles in maintaining health. Fruits, including grains, occupy a central role in world agriculture.

Adapted to a wide range of climates and soils, fruits are grown everywhere except the Arctic and theAntarctic.

In the north and south temperate zones, the growing season typically extends from spring to autumn.

Here, fields of corn, wheat, and oats dominate thefarm landscape, along with orchards of plums, peaches, apples, and pears.

Tomato, squash, eggplant, grapes, strawberries, and blueberries are also important crops inthese regions.

Leading producers of fruits grown in temperate regions include the United States, which produces over 229 million metric tons of corn and 894,000metric tons of strawberries; China, with 20.4 million metric tons of apples and 25.5 million metric tons of tomatoes; and Italy, with 7.9 million metric tons of grapes.. »