Fruit

• 1. Botanical Definition And Classification

  ›

  In botany, a fruit is the seed-bearing structure in flowering plants that forms from the ovary after flowering. This definition includes structures like nuts, bean pods, corn kernels, tomatoes, and wheat grains. These items are not commonly called fruits in everyday language but fit the scientific criteria. A nut is actually a type of fruit rather than just a seed. A seed itself is defined as a ripened ovule within this system. The outer layer of most fruits is known as the pericarp. It typically surrounds the seeds and may be described in three layers: the epicarp, mesocarp, and endocarp. Some fruits bear a prominent pointed terminal projection which is said to be beaked. Plant scientists have classified fruits into three main groups based on how they develop. Simple fruits result from the ripening of a simple or compound ovary in a single flower with a single pistil. Aggregate fruits develop from a single flower that presents numerous simple pistils. Multiple fruits form from a cluster of flowers also called an inflorescence.

• 2. Culinary Versus Botanical Distinctions

  ›

  Common language terms used for fruit and seeds differ significantly from botanical classifications. In culinary usage, a fruit is the sweet- or sour-tasting produce of a specific plant such as a peach, pear, or lemon. Vegetables are typically savory or non-sweet produce including zucchini, lettuce, broccoli, and tomato. However, some vegetables like sweet potatoes may taste sweet. Many common items botanically classified as fruit are called vegetables by people. Examples include cucumber, pumpkin, squash, beans, peanuts, peas, corn, eggplant, bell pepper, and tomato. Many spices are fruits in botanical terms including black pepper, chili pepper, cumin, and allspice. Rhubarb is often called a fruit when used in pies but its edible part is actually the leaf stalk or petiole. Edible gymnosperm seeds are often given fruit names like ginkgo nuts and pine nuts. A cereal grain such as corn, rice, or wheat is technically a kind of fruit termed a caryopsis. The Supreme Court of the United States ruled on this matter in Nix v. Hedden to determine legal definitions for taxation purposes.

• 3. Developmental Biology Of Fruits

  ›

  A fruit results from the fertilizing and maturing of one or more flowers. The gynoecium contains the stigma-style-ovary system centered in the flower-head. Inside the ovary are one or more ovules where double fertilization begins. A female gametophyte produces an egg cell for the purpose of fertilization. Pollination starts with the movement of pollen from the stamens to the stigma-style-ovary system within the flower-head. After pollination, a pollen tube grows from the deposited pollen through the stigma down the style into the ovary to the ovule. Two sperm are transferred from the pollen to a megagametophyte. One sperm unites with the egg forming a zygote while the second enters the central cell forming the endosperm mother cell. Later the zygote gives rise to the embryo of the seed. The endosperm mother cell gives rise to endosperm which is nutritive tissue used by the embryo. Fruit formation is associated with meiosis a central aspect of sexual reproduction in flowering plants. During meiosis homologous chromosomes replicate recombine and randomly segregate. Union of haploid nuclei from pollen and ovule leads to the formation of a diploid zygote that can develop into an embryo within the emerging seed.

• 4. Seed Dispersal Mechanisms

  ›

  Variations in fruit structures largely depend on the modes of dispersal applied to their seeds. Some fruits present outer skins coated with spikes or hooked burrs to attach themselves to animal hair or clothing. These plants are termed zoochorous including common examples like cocklebur unicorn plant, and beggarticks. Fleshy produce typically appeals to hungry animals so seeds are carried away and later deposited at a distance. Nutritious oily kernels motivate birds and squirrels to hoard them burying them in soil for retrieval during winter. Other fruits have evolved flattened wings or helicopter-like blades such as elm maple and tuliptree to increase wind dispersal. Dandelion milkweed, and salsify possess tiny parachutes to travel further via air currents. Coconut fruits can float thousands of miles in the ocean spreading their seeds across vast distances. Nipa palm and screw pine also disperse via water. Some fruits have propulsive mechanisms that fling seeds substantial distances up to several meters in cases like the sandbox tree. Explosive dehiscence allows impatiens and squirting cucumber to launch seeds far from the parent plant.

• 5. Human Agriculture And Consumption

  ›

  A large variety of fruits are commercially valuable as human food ranging from apples to berries to watermelon. They are eaten both fresh and as jams marmalade and other fruit preserves. Fruits are used extensively in manufactured foods like cakes cookies baked goods flavorings ice cream yogurt canned vegetables frozen vegetables and meals. Beverages include fruit juices and alcoholic drinks such as brandy fruit beer and wine. Spices like vanilla black pepper paprika and allspice are derived from berries. Olive fruit is pressed for olive oil and similar processing applies to other oil-bearing fruits. Some fruits are available all year round while others like blackberries and apricots in the UK are subject to seasonal availability. All fruits benefit from proper post-harvest care with the plant hormone ethylene causing ripening. Maintaining most fruits in an efficient cold chain extends shelf life. A meta-analysis of 83 studies showed fruit or vegetable consumption is associated with reduced markers of inflammation. Various culinary fruits provide significant amounts of fiber and water and many are generally high in vitamin C. Regular consumption of fruit is generally associated with reduced risks of several diseases and functional declines associated with aging.

• 6. Nonfood Applications And Cultural Impact

  ›

  Because fruits have been a major part of the human diet various cultures developed uses beyond food. Bayberry fruits provide wax often used to make candles. Many dry fruits serve as decorations or in dried flower arrangements including annual honesty cotoneaster lotus milkweed unicorn plant, and wheat. Ornamental trees and shrubs are cultivated for colorful fruits including beautyberry cotoneaster holly pyracantha skimmia, and viburnum. Fruits of opium poppy are the source of opium containing drugs codeine and morphine. Osage orange fruits are used to repel cockroaches. Many fruits provide natural dyes such as cherry mulberry sumac, and walnut. Dried gourds function as bird houses cups dishes musical instruments and water jugs. Pumpkins are carved into Jack-o'-lanterns for Halloween. The fibrous core of the mature and dry Luffa fruit serves as a sponge. The spiny fruit of burdock inspired the invention of Velcro. Coir fiber from coconut shells makes brushes doormats floor tiles insulation mattresses sacking and growing medium. The hard and colorful grain fruits of Job's tears decorate jewelry garments and ritual objects.