Fruit
The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state, such as apples, oranges, grapes, strawberries, juniper berries and bananas. Seed-associated structures that do not fit these informal criteria are usually called by other names, such as vegetables,pods, nut, ears and cones.
In biology (botany), a "fruit" is a part of a flowering plant that derives from specific tissues of the flower, mainly one or more ovaries. Taken strictly, this definition excludes many structures that are "fruits" in the common sense of the term, such as those produced by non-flowering plants (like juniper berries, which are the seed-containing female cones of conifers), and fleshy fruit-like growths that develop from other plant tissues close to the fruit (accessory fruit, or more rarely false fruit or pseudocarp), such as cashew fruits. Often the botanical fruit is only part of the common fruit, or is merely adjacent to it. On the other hand, the botanical sense includes many structures that are not commonly called "fruits", such as bean pods, corn kernels, wheat grains, tomatoes, the section of a fungus that produces spores, and many more. However, there are several variants of the biological definition of fruit that emphasize different aspects of the enormous variety that is found among plant fruits.
Fruits (in either sense of the word) are the means by which many plants disseminate seeds. Most plants bearing edible fruits, in particular,coevolved with animals in a symbiotic relationship as a means for seed dispersal and nutrition, respectively; in fact, many animals (includinghumans to some extent) have become dependent on fruits as a source of food. Fruits account for a substantial fraction of world's agriculturaloutput, and some (such as the apple and the pomegranate) have acquired extensive cultural and symbolic meanings.
Many fruits that, in a botanical sense, are true fruits are actually treated as vegetables in cooking and food preparation, because they are not particularly sweet. These culinary vegetables include cucurbits (e.g., squash, pumpkin, and cucumber), tomatoes, peas, beans, corn,eggplant, and sweet pepper. In addition, some spices, such as allspice and chilies, are fruits, botanically speaking. In contrast, occasionally a culinary "fruit" is not a true fruit in the botanical sense. For example, rhubarb is often referred to as a fruit, because it is used to make sweet desserts such as pies, though only the petiole of the rhubarb plant is edible. In the culinary sense of these words, a fruit is usually any sweet-tasting plant product, especially those associated with seed(s), a vegetable is any savoury or less sweet plant product, and a nut is any hard, oily, and shelled plant product.
Technically, a cereal grain is also a kind of fruit, a kind which is termed a caryopsis. However, the fruit wall is very thin, and is fused to the seed coat, so almost all of the edible grain is actually a seed. Therefore, cereal grains, such as corn, wheat and rice are better considered as edible seeds, although some references do list them as fruits. Edible gymnosperm seeds are often misleadingly given fruit names, e.g., pine nuts, ginkgo nuts, and juniper berries.
Fruit Development
A fruit results from maturation of one or more flowers, and the gynoecium of the flower(s) forms all or part of the fruit.
Inside the ovary/ovaries are one or more ovules where the megagametophyte contains the mega gamete or egg cell. Afterdouble fertilization, these ovules will become seeds. The ovules are fertilized in a process that starts with pollination, which involves the movement of pollen from the stamens to the stigma of flowers. After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule and two sperm are transferred from the pollen to the megagametophyte. Within the megagametophyte one of the two sperm unites with the egg, forming a zygote, and the second sperm enters the central cell forming the endosperm mother cell, which completes the double fertilization process. Later the zygote will give rise to the embryo of the seed, and the endosperm mother cell will give rise to endosperm, a nutritive tissue used by the embryo.
As the ovules develop into seeds, the ovary begins to ripen and the ovary wall, the pericarp, may become fleshy (as in berries ordrupes), or form a hard outer covering (as in nuts). In some multiseeded fruits, the extent to which the flesh develops is proportional to the number of fertilized ovules. The pericarp is often differentiated into two or three distinct layers called theexocarp (outer layer, also called epicarp), mesocarp (middle layer), and endocarp (inner layer). In some fruits, especially simple fruits derived from an inferior ovary, other parts of the flower (such as the floral tube, including the petals, sepals, and stamens), fuse with the ovary and ripen with it. In other cases, the sepals, petals and/or stamens and style of the flower fall off. When such other floral parts are a significant part of the fruit, it is called an accessory fruit. Since other parts of the flower may contribute to the structure of the fruit, it is important to study flower structure to understand how a particular fruit forms.
Fruits are so diverse that it is difficult to devise a classification scheme that includes all known fruits. Many common terms for seeds and fruit are incorrectly applied, a fact that complicates understanding of the terminology. Seeds are ripened ovules; fruits are the ripened ovaries or carpels that contain the seeds. To these two basic definitions can be added the clarification that in botanical terminology, a nut is not a type of fruit and not another term for seed, on the contrary to common terminology.
There are three general modes of fruit development:
- Apocarpous fruits develop from a single flower having one or more separate carpels, and they are the simplest fruits.
- Syncarpous fruits develop from a single gynoecium having two or more carpels fused together.
- Multiple fruits form from many different flowers.
Plant scientists have grouped fruits into three main groups, simple fruits, aggregate fruits, and composite or multiple fruits. The groupings are not evolutionarily relevant, since many diverse plant taxa may be in the same group, but reflect how the flower organs are arranged and how the fruits develop.
The development sequence of a typical drupe, the nectarine (Prunus persica) over a 7.5 month period,
from bud formation in early winter to fruit ripening in midsummer.
Epigynous berries are simple fleshy fruit. Clockwise from top right:
Simple Fruits
Simple fruits can be either dry or fleshy, and result from the ripening of a simple or compound ovary in a flower with only one pistil. Dry fruits may be either dehiscent (opening to discharge seeds), or indehiscent (not opening to discharge seeds).[15] Types of dry, simple fruits, with examples of each, are:
- achene - Most commonly seen in aggregate fruits (e.g. strawberry)
- capsule – (Brazil nut)
- caryopsis – (wheat)
- Cypsela - An achene-like fruit derived from the individual florets in a capitulum (e.g. dandelion).
- fibrous drupe – (coconut, walnut)
- follicle – is formed from a single carpel, and opens by one suture (e.g. milkweed). More commonly seen in aggregate fruits (e.g. magnolia)
- legume – (pea, bean, peanut)
- loment - a type of indehiscent legume
- nut – (hazelnut, beech, oak acorn)
- samara – (elm, ash, maple key)
- schizocarp – (carrot seed)
- silique – (radish seed)
- silicle – (shepherd's purse)
- utricle – (beet)
Fruits in which part or all of the pericarp (fruit wall) is fleshy at maturity are simple fleshy fruits. Types of fleshy, simple fruits (with examples) are:
- berry – (redcurrant, gooseberry, tomato, cranberry)
- stone fruit or drupe (plum, cherry, peach, apricot, olive)
Each flower will become a blackberry-like aggregate fruit.
An aggregate fruit, or etaerio, develops from a single flower with numerous simple pistils.
- Magnolia and Peony, collection of follicles developing from one flower.
- Sweet gum, collection of capsules.
- Sycamore, collection of achenes.
- Teasel, collection of cypsellas
- Tuliptree, collection of samaras.
The pome fruits of the family Rosaceae, (including apples, pears, rosehips, and saskatoon berry) are a syncarpous fleshy fruit, a simple fruit, developing from a half-inferior ovary.
Schizocarp fruits form from a syncarpous ovary and do not really dehisce, but split into segments with one or more seeds; they include a number of different forms from a wide range of families. Carrot seed is an example.
Aggregate fruits form from single flowers that have multiple carpels which are not joined together, i.e. each pistil contains one carpel. Each pistil forms a fruitlet, and collectively the fruitlets are called an etaerio. Four types of aggregate fruits include etaerios of achenes, follicles, drupelets, and berries. Ranunculaceae species, including Clematis and Ranunculus have an etaerio of achenes, Calotropis has an etaerio of follicles, and Rubus species like raspberry, have an etaerio of drupelets.Annona have Etaerio of berries.
The raspberry, whose pistils are termed drupelets because each is like a small drupe attached to the receptacle. In some bramble fruits (such as blackberry) the receptacle is elongated and part of the ripe fruit, making the blackberry an aggregate-accessory fruit. The strawberry is also an aggregate-accessory fruit, only one in which the seeds are contained in achenes. In all these examples, the fruit develops from a single flower with numerous pistils.
Detail of raspberry flower.
Multiple fruit
Multiple fruits are fruits that are formed from a cluster of flowers (called an inflorescence). Each flower in the inflorescence produces a fruit, but these mature into a single mass. Examples are the pineapple, fig, mulberry,osage-orange, and breadfruit.
In some plants, such as this noni, flowers are produced regularly along the stem and it is possible to see together examples of flowering, fruit development, and fruit ripening
In the photograph on the left, stages of flowering and fruit development in the noni or Indian mulberry (Morinda citrifolia) can be observed on a single branch. First an inflorescence of white flowers called a head is produced. After fertilization, each flower develops into a drupe, and as the drupes expand, they become connate (merge) into a multiple fleshy fruit called a syncarp. There are also many dry multiple fruits.
Other examples of multiple fruits:
- Platanus, teasel, Asteraceae multiple achenes from multiple flowers, in a single fruit structure
- Mulberry, multiple flowers form one fruit
- Common Fig, multiple flowers form one fruit (inside the fruit)
Similar structures are formed from single flowers that have more than one pistil, and these are called aggregate fruits, e.g.:
- Strawberry, aggregate of achenes on a fleshy receptacle
- Tuliptree, aggregate of samaras.
- Sweet gum, aggregate of capsules.
- Magnolia, aggregate of follicles.
Strawberry is a kind of multiple fruit
To summarize common types of fleshy fruit (examples follow in the table below):
- Berry – simple fruit and seeds created from a single ovary
- Pepo – Berries where the skin is hardened, like cucurbits
- Hesperidium – Berries with a rind and a juicy interior, like most citrus fruit
- Compound fruit, which includes:
- Aggregate fruit – with seeds from different ovaries of a single flower
- Multiple fruit – fruits of separate flowers, merged or packed closely together
- Accessory fruit – where some or all of the edible part is not generated by the ovary
Types Of Fleshy Fruit
True Berry
| Blackcurrant, Redcurrant, Gooseberry, Tomato, Eggplant, Guava, Lucuma, Chili pepper, Pomegranate, Kiwifruit, Grape, Cranberry, Blueberry |
Pepo
| Orange, Lemon,Lime, Grapefruit |
| Blackberry,Raspberry,Boysenberry |
| Pineapple, Fig,Mulberry, Hedge apple |
