What is a Fruit? This question is always asked in association with another question What is a vegetable? . The former question is asked repeatedly and without doubt will be asked over and over again.
The reason is that the term fruit has many meanings based on various criteria, even in crop agriculture. It can refer to a part of a plant, a type of tree or crop, or a particular food item. As to vegetables, there is a special classification called fruit vegetables which refers to crops in which fruits are harvested primarily for use in culinary preparations, such as tomato and squash.
Indeed, based on common usage, fruits refer to the plant structure having sweet, edible portions and generally consumed raw as contrasted to vegetables which refer to any succulent plant parts which are generally consumed cooked.
To underscore the importance of clarifying what is a fruit, here are some usage or reference to the term: (1) Technically, the “kernel” of corn and the “grain” of rice are a fruit called “caryopsis”. (a botanical reference to fruit as a plant organ); (2) The mango tree is a fruit. (referring to the mango tree as a fruit crop); and (3) This banana fruit tastes good. (referring to the banana fruit as a food item that is generally consumed raw). To add to the confusion, here is a common but contrasting statement: "I will go to the market to buy fresh tomato vegetable" (for consumption of the tomato fruit as a vegetable).
In fact, the question Is tomato a fruit or a vegetable? is not new. The question is so valid that it became a legal issue more than a century ago.
On May 10, 1893, the Supreme Court of the United States settled the controversy on what is a fruit and what is a vegetable within the meaning of the Tariff Act of March 3, 1883 which imposed a duty on imported vegetables. In its ruling declaring tomato as vegetable, it said:
Botanically speaking, tomatoes are the fruit of a vine (emphasis supplied), just as are cucumbers, squashes, beans, and peas. But in the common language of the people, whether sellers or consumers of provisions, all these are vegetables (emphasis supplied) which are grown in kitchen gardens, and which, whether eaten cooked or raw, are, like potatoes, carrots, parsnips, turnips, beets, cauliflower, cabbage, celery, and lettuce, usually served at dinner in, with, or after the soup, fish, or meats which constitute the principal part of the repast, and not, like fruits generally, as dessert. (Nix v. Hedden, 149 U.S. 304 (1893), retrieved December 21, 2010 from http://caselaw.lp.findlaw.com/cgi-bin/getcase.pl?court=us&vol=149&invol=304)
This page is about fruit as a plant organ.
The fruit is a plant organ that is considered as a reproductive part of the plant shoot system in the angiosperms, along with the flower and seed. It is distinct from the vegetative parts of the plant shoot which consist of the stem and leaves. Its participation in plant reproduction, however, is indirect. Its main functions are to enclose and protect the seed and to help in its dispersal.
The fruit is unique to the angiosperms or flowering plants, having developed from a flower which is found only in this group of plants. It consists of a pericarp that is responsible for the “enclosed” or “covered” seeds of the angiosperms. In contrast, gymnosperm means “naked seed.”
What is a Fruit: Fruit Parts
The fruit develops from a flower after fertilization, and consists of a ripened (or matured) ovary or group of ovaries usually containing seed or seeds. It may also include the receptacle, as well as other flower parts such as the sepals, petals, stamens and portions of the style.
In some plants, seedless fruits develop without fertilization through a process known as parthenocarpy.
During fruit development, the ovary wall thickens to become the pericarp which surrounds the seed or seeds. The pericarp consists of three layers of tissue: epicarp or exocarp, mesocarp and endocarp. These fruit parts may be clearly separated or they may be tightly fused so that they are difficult to distinguish from each other. In cashew (Anacardium occidentale), the fruit type is that of a kidney-shaped drupaceous nut with a resinous hard pericarp. The “cashew apple” is a pseudofruit or false fruit consisting of an enlarged and swollen pedicel.
The exocarp is the outermost part of the pericarp, and is often the visible skin or peel of the fruit. It consists of the epidermal and subepidermal layers of fruits, with various classifications based on texture and appearance such as glabrous (no pubescence), glaucous (waxy bloom), finely pubescent, and densely pubescent. It may also be represented by a hard, thick, or leathery rind. The exocarp is one of the basis in the classification of fruits into various fruit types.
The mesocarp is the middle layer of the pericarp between the exocarp and endocarp. In mango, the mesocarp is the edible, fleshy portion that is eaten between the skin and the seed. This edible portion is the one that is, in common usage, associated with what is a fruit. In young coconut, the mesocarp is relatively soft but becomes the dry and fibrous husk of the mature fruit.
The endocarp is the innermost layer of the pericarp, the part that immediately encloses the seeds. It occurs in various forms and texture ranging from thin and papery to hard and stony as in the fruit type called drupe. In mango fruits, the endocarp is thick, woody and fibrous; in coconut it is represented by a hard shell.
Some fruits are supplied with appendages mainly for the purpose of dispersal. The fruits may be supplied with winged appendages, tufts of hairs, hooked or barbed bristles, spines, or with some glandular projections.
(Ben G. Bareja, May 2011)