A matured carpel or group of carpels (the basic units of the gynoecium or female part of the flower) with or without seeds, and with or without other floral or shoot parts (accessory structures) united to the carpel or carpels. Carpology is the study of the morphology and anatomy of fruits. The ovary develops into a fruit after fertilization and usually contains one or more seeds, which have developed from the fertilized ovules. Parthenocarpic fruits usually lack seeds. Fruitlets are the small fruits or subunits of aggregate or multiple fruits. Flowers, carpels, ovaries, and fruits are, by definition, restricted to the flowering plants (angiosperms), although fruitlike structures may enclose seeds in certain other groups of seed plants. The fruit is of ecological significance because of seed dispersal. See Seed
A fruit develops from one or more carpels. Usually only part of the gynoecium, the ovary, develops into a fruit; the style and stigma wither. Accessory (extracarpellary or noncarpellary) structures may be closely associated with the carpel or carpels and display various degrees of adnation (fusion) to them, thus becoming part of the fruit. Such accessory parts include sepals (as in the mulberry), the bases of sepals, petals, and stamens united into a floral tube (apple, banana, pear, and other species with inferior ovaries), the receptacle (strawberry), the pedicel and receptacle (cashew), the peduncle (fleshy part of the fig), the involucre composed of bracts and bracteoles (walnut and pineapple), and the inflorescence axis (pineapple). See Flower
A fruit derived from only carpellary structures is called a true fruit, or, because it develops from a superior ovary (one inserted above the other floral parts), a superior fruit (corn, date, grape, plum, and tomato). Fruits with accessory structures are called accessory (or inaptly, false or spurious) fruits (pseudocarps), or, because of their frequent derivation from inferior ovaries (inserted below the other floral parts), inferior fruits (banana, pear, squash, and walnut).
Fruits can be characterized by the number of ovaries and flowers forming the fruit. A simple fruit is derived form one ovary, an aggregate fruit from several ovaries of one flower (magnolia, rose, and strawberry). A multiple (collective) fruit is derived from the ovaries and accessory structures of several flowers consolidated into one mass (fig, pandan, pineapple, and sweet gum).
The fruit wall at maturity may be fleshy or, more commonly, dry. Fleshy fruits range from soft and juicy to hard and tough. Dry fruits may be dehiscent, opening to release seeds, or indehiscent, remaining closed and containing usually one seed per fruit. Fleshy fruits are rarely dehiscent.
The pericarp is the fruit wall developed from the ovary. In true fruits, the fruit wall and pericarp are synonymous, but in accessory fruits the fruit wall includes the pericarp plus one or more accessory tissues of various derivation. Besides the fruit wall, a fruit contains one or more seed-bearing regions (placentae) and often partitions (septa).
Anatomically or histologically, a fruit consists of dermal, ground (fundamental), and vascular systems and, if present, one or more seeds. After fertilization the ovary and sometimes accessory parts develop into the fruit; parthenocarpy is fruit production without fertilization. The fruit generally increases in size and undergoes various anatomical changes that usually relate to its manner of dehiscence, its mode of dispersal, or protection of its seeds. The economically important, mainly fleshy fruits have received the most histological and developmental study.
Size increase of fruits is hormonally controlled and results from cell division and especially from cell enlargement. Cell number, volume, and weight thus control fruit weight. Cell division generally is more pronounced before anthesis (full bloom); cell enlargement is more pronounced after.
Large fruits generally require additional anatomical modifications for nutrition or support or both. The extra phloem in fruit vascular bundles and the often increased amount of vascular tissue in the fruit wall and septa supply nutrients to the developing seeds and, especially in fleshy fruits, to the developing walls. Large, especially fleshy fruits (apple, gourd, and kiwi) usually contain proportionally more vascular tissue than small fruits. Vascular tissue also serves for support and in lightweight fruits may be the chief means of support.
Crystals, tannins, and oils commonly occur in fruits and may protect against pathogens and predators. The astringency of tannins, for example, may be repellent to organisms. With fruit maturation, tannin content ordinarily decreases, so the tannin repellency operative in early stages is superseded in fleshy fruits by features (tenderness, succulence, sweetness through odor and increased sugar content, and so on) attractive to animal dispersal agents. Many fruits are dispersed by hairs, hooks, barbs, spines, and sticky mucilage adhering the fruit to the surface of the dispersal agent. Lightweight fruits with many air spaces or with wings or plumes may be dispersed by wind or water. Gravity is always a factor in dispersal of fruits and seeds.
Fruits are complex symbols, representing everything from transcendence, to the self, to abundance, to spiritual knowledge. (See entries on particular fruits for more information.) The dreaming mind often literalizes common verbal expressions in an effort to convey something to the conscious mind, so fruit dreams can also indicate anything along the lines of “first fruits,” “forbidden fruit,” “fruitcake,” and so on.
an organ of angiospermous plants that arises from the flower and serves to form, protect, and disseminate the seeds enclosed in it. The fruit is formed after fertilization (except for parthenocarpous fruit). In the more primitive plants, such as Ranunculaceae, the fruit originates only from an expanded and modified gynoecium that is attached to the torus. Its formation occurs without the participation of the other organs making up the flower. In the process of evolution, owing to the development of adaptations for the protection and dissemination of seeds, the following floral parts acquired ever greater importance in fruit formation: the torus (strawberry), gynophore (Capparis, Caryo-phyllaceae), perianth (sugar beet, mulberry), calyx (henbane), corolla and stamens (clover), hypanthium of leaf origin (apple), flowering glumes and lemmas (grasses), and bracts (orache). The outer part of the fruit is the pericarp. The seeds develop inside the fruit in nidi and on enations (placentas).
In many classifications, a distinction is usually made between true fruit (formed from the expanded ovary) and accessory, or spurious, fruits (formed from the ovary and additional floral parts). True fruits include simple fruits, formed from a single pistil, and aggregate fruits, formed from a multiple apocarpous gynoecium. Simple fruits are designated according to the consistency of the pericarp as being either dry or fleshy. Dry fruits may be polyspermous dehiscent (follicle, legume, silique, utricle, capsule, pyxidium), polyspermous indehiscent (segmented bean, segmented pod), schizocarpic (double-winged fruit, cremocarp), and monospermous indehiscent (nut, nutlet, samara, achene, caryopsis). Fleshy fruits include those that are polyspermous (berry, pepo, pome, hesperidium, balausta) and those that are monospermous (drupe). Aggregate fruits proceeding from the names of simple fruits include aggregate follicles, aggregate achenes, and aggregate drupes.
More modern morphogenetic classifications of fruits take into account the aggregate of characters that are important in elucidating evolution: the structure of the gynoecium; the character and degree of participation of organs other than the gynoecium in fruit formation; the number, distribution, and means of concrescence of the carpels; and the number of seeds and their type of attachment. Morphogenetic classifications make a distinction between apocarpous fruits (formed from nonconcresced pistils) and coenocarpous fruits (formed from a gamophyllous gynoecium).
Coenocarpous fruits may be syncarpous (bilocular or multi-locular, with axile placentation), paracarpous (unilocular, with parietal placentation), or lysicarpous (unilocular, with free central placentation). Depending on the degree of participation of various nonpistillate organs in fruit formation, the fruit may be naked, have a spathe or a sheath, or be submerged. Its position with respect to the ovary is said to be superior, inferior, or half-inferior.
Apocarpous fruits are the most primitive. The parent type is considered the naked superior spiral multifollicular fruit (globe-flower). In the process of evolution, as a result of a decrease in the number of carpels, the parent type developed into pentafol-licular, trifollicular, bifollicular, and unifollicular fruits (monkshood, larkspur). A change in the relative positions of the carpels resulted in the evolution of a cyclical multiple fruit (Cras-sulaceae), and the formation of a fleshy pericarp resulted in a fleshy multiple fruit (lemon tree). A decrease in the number of seeds to one led to the formation of a multiple nutlet (Ranunculus). Similarly, a decrease in the number of carpels in the fleshy multifollicular fruit resulted in the formation of a fleshy unifollicle (baneberry) and mononutlet (hornwort). Also descended from the multifollicular fruit is the typical legume, which has a different number of carpels. The legume dehisces not only along its ventral suture but also along its middle vein. The multiple drupe (raspberry) possibly descended from the multiple fruit as a result of a decrease in the number of seeds and a change in the consistency of the pericarp, whereas the single drupe (cherry) apparently evolved in the same way from the pentafolli-cle. Caryopses (Gramineae), which are closely related to the fruits of certain palms, are often included among apocarpous fruits.
Syncarpous fruits probably arose from cyclical multiple fruits as a result of the concrescence of the carpels. The superior syncarpous capsule—a collective fruit—was formed from the superior ovary. As a result of change in the method of dehiscence, there arose the rhegma (spurge) and the sterigma (Geranium). The carcerulus (linden) arose as a result of underdevelopment of the nidi and all the ovules but one. Underdevelopment of all the ovules except two resulted in the formation of the samara (maple). The formation of a false septum in the nidi and of four monospermous outgrowths of the pericarp (eremi) led to the origin of the coenobium (Boraginaceae, Labiatae), and the evolution of a fleshy pericarp led to the formation of numerous syncarpous berries (grapes, lily of the valley, nightshade), syncarpous drupes (Rhamnus), and hesperidia (citrus fruits). From the inferior ovary there developed the inferior syncarpous capsule (Iridaceae), the pomegranate, the acorn (oak), the nut (filbert), the pome (apple), the inferior syncarpous berry (honeysuckle), the inferior syncarpous drupe (elder), the cremocarp (Umbelliferae), and the diachene (Rubiaceae).
Paracarpous fruits originated from syncarpous fruits or directly from apocarpous fruits (for example, the poppy head in the poppy). To these belong the superior paracarpous capsule (violet), the siliqua and silicle (Cruciferae), the paracarpous berry (Capparis), and the drupe (palms). The caryopsis of Gramineae is often also assigned to this group. Inferior paracarpous fruits include the inferior paracarpous capsule (Orchidaceae), the achene (Compositae), and the pepo (Cucurbitaceae). Lysicarpous fruits are descended from syncarpous ones. They include the lysicarpous capsule (Caryophyllaceae, Primulaceae), the pyxidium (Anagallis), and the drupe (Myrsinaceae).
The fruits of a plant protect and disseminate seeds. Before maturation, the pericarp protects the seeds from desiccation, mechanical injury, and consumption by animals. (During this period the seeds often accumulate poisonous, acidic, or astringent substances, which disappear when the fruit ripens.) The pericarp of indehiscent fruits protects mature seeds from being eaten or from sprouting prematurely. The distribution of fruits is effected by wind, water, animals, and man. Fruits distributed by wind (anemochory) have adaptations that facilitate flight: a pappus (Compositae), a feathery tail (Clematis, Dryas), winglike appendages (maple, elm), or a bract of the inflorescence (linden). In the pericarps of fruits distributed by water (hydrochory) air-bearing tissue and cavities develop, or external appendages that hold air form (sedge and many aquatic plants). Fruits equipped with such clinging appendages as hooks, bristles, or thorns (stickseed, carrot) adhere to animals and to human clothing. Fruits with fleshy appendages (melick, some sedges) are distributed by ants (myrmechory), and fruits that have a fleshy pericarp are distributed by birds (ornithochory) or other animals that eat fruit (zoochory). Man also participates in the distribution of fruits, both consciously and unconsciously. The fruits of weeds and some other plants are transported as contaminants in planting material and in organic fertilizers. Cultivating and transport equipment also disseminate fruits.
Many fruits contain large quantities of the most important nutritional substances (proteins, fats, carbohydrates, and vitamins). They constitute an essential part of the diet in fresh, canned, or processed form. Many are used as livestock feed or as a source of medicinal substances and dyes. The fruits of weeds contaminate soil, decrease the quality of commercial and forage grains, and may cause poisoning. The morphological characteristics of fruits enable identification of plant species. The science of fruits is carpology.
N. N. KADEN