Fruits

Study of fruit and fruit bearing plants is called pomology. The precise botanical definition of “fruit” is: the seed bearing structure (or the ripened ovary as not all fruit have seeds) in flowering plants.

1.0True Fruit (The ripened ovary)

Post-ripening, the ovary wall transforms into what is known as the pericarp or the fruit wall. This pericarp may exhibit varying characteristics, such as being thick and fleshy, thick and hard, or thin and soft. In fleshy fruits, the pericarp typically consists of three layers:

Epicarp: This is the outermost layer, which can vary in thickness and texture. It forms the fruit's outermost covering, often referred to as the rind.

Mesocarp: Situated between the outer epicarp and the innermost endocarp, the mesocarp is usually thick and fleshy in fruits like mangoes, peaches, and dates. However, the mesocarp comprises a fibrous material known as coir in fruits like coconuts.

Endocarp: Serving as the innermost layer of the pericarp, the endocarp may be membranous and thin (e.g., oranges, dates) or thick and hard (e.g., mangoes, coconuts).

Additionally, some fruits exhibit a phenomenon known as false fruit or pseudocarp, where parts of the flower other than the ovary, such as the thalamus, calyx, or inflorescence, are modified into fruit or contribute to fruit formation. Examples of false fruits include apples, strawberries, pears, mulberries, figs, and cashew nuts. In the case of fruits like apples, strawberries, and cashews, the thalamus also plays a role in fruit development. These fruits, which involve such modifications, are termed false fruits.

However, in cases where fruit formation occurs without ovary fertilization, these fruits are termed parthenocarpic. A prime example of this phenomenon is seen in seedless fruits such as grapes and bananas.

2.0Classification of Fruits

On the basis of whether fruit develops from the ovary or not

• True Fruit- True fruits are those that develop solely from the ovary. Mango, Coconut, and other tropical fruits are examples.
• Pseudocarp or False Fruit- The fruit is not formed by the ovary in some fruits. Some flower parts, such as the thalamus, inflorescence, and calyx, are modified to become a part of the fruit. These are referred to as false fruits. Apple, strawberry, and other fruits are examples.

On the basis of development: After sexual reproduction, the ovary develops into a fruit. furthermore three different types of fruits depending on the development:

• Apocarpous:  The fruit is developed from one flower and one or more carpels. Apocarpous is known as the most simple fruit. 
• Syncarpous: The fruit is formed from one or two carpels and one gynoecium.
• Multiple: The fruit is formed from groups of flowers, also known as inflorescence.

3.0Types of Fruits (Based on number of ovaries or types of ovaries involved)

1. Simple fruits. 2. Aggregate fruits(Etaerio) 3. Composite fruits. 

Simple Fruits

Simple fruits develop from either a monocarpellary gynoecium or a multicarpellary, syncarpous gynoecium, forming only one fruit by the gynoecium. There are two main types of simple fruits: Fleshy fruits and Dry fruits.

1. Fleshy Fruits: For fleshy fruits, the fruit wall (pericarp) is differentiated into three layers: epicarp, mesocarp, and endocarp. These fruits are indehiscent, meaning they do not naturally split open to release seeds. Fleshy fruits are further classified into the following types:

• Drupe Fruits: Drupe fruits develop from monocarpellary superior ovaries and contain a single seed. The endocarp of these fruits is hard and stony, hence they are also referred to as stony fruits. Examples include mango, coconut, almond, peach, walnut, and plum. 

In mangoes, the outermost thin rind is known as the epicarp, the middle edible fleshy part is the mesocarp, and the inner stony hard layer is the endocarp. 

In plums, both the epicarp and mesocarp are edible, while the endocarp is stony. The hard covering of almonds and walnuts is the endocarp, with the edible part being the seed.

In coconuts, the epicarp is hard and thin, the mesocarp is thick and fibrous, and the endocarp is hard, protecting the seed. The coconut's sweet water and edible part are the liquid and solid endosperm, respectively.

• Berry: Berries develop from either monocarpellary or multicarpellary, syncarpous ovaries, which may be superior or inferior. Placentation is axile; generally, the epicarp is a thin membrane-like layer with seeds embedded in the fleshy part. Initially, the seeds are attached to the placenta of the fruit, but upon maturation, they detach and are spread randomly in the fleshy part. Examples include tomatoes, grapes, eggplants, guavas, bananas, dates, and betel nuts.

• Pepo: Pepo fruits develop from inferior ovaries and have parietal placentation, although they may appear axile due to placental swelling, and the seed remains attached to the placenta. Examples include fruits of the Cucurbitaceae family, such as cucumbers, watermelons, pumpkins, bitter gourds, and muskmelons.
• Pome: Pome fruits develop from inferior ovaries and have an enlarged thalamus. Examples include apples and pears. These fruits are considered false fruits, with the fleshy, swollen thalamus being the edible part.
• Hesperidium: Hesperidium fruits have axile placentation and are mainly found in plants of the Rutaceae family. Examples include oranges and lemons. The epicarp of these fruits consists of a thick rind with numerous oil glands, while the mesocarp is a white fibrous structure attached to the epicarp. The membranous endocarp projects inward to form chambers, and glandular hairs on the inner side of the endocarp produce edible, juicy hairs.

• Balausta: Balausta fruits develop from inferior ovaries, with the calyx persisting as a crown. The fleshy and juicy testa of the seed is the edible part. An example is the pomegranate (Punica granatum).

2. Dry Fruits: 

Simple dry fruits exhibit various characteristics based on their pericarp (fruit wall) and dispersal methods. They can be categorized into three main groups: Indehiscent, Dehiscent, and Schizocarpic.

Indehiscent Fruits: These fruits do not rupture upon maturity and typically remain closed. They are usually small-sized and contain a single seed.

• Caryopsis: These small, one-seeded dry fruits develop from a monocarpellary, superior ovary. The pericarp fuses with the seed coat, forming a joint surface. Typical examples are found in the Gramineae family, such as wheat, rice, and maize.

• Cypsela: Derived from a bi-carpellary, syncarpous, inferior ovary, the cypsela's pericarp and seed coat are distinct. It features a pappus, a bunch of hairs aiding dispersal, and a modified calyx. Examples include plants from the Compositae family, like sunflowers and marigolds.
• Achene: Achene fruits have a pericarp separate from the seed coat and lack a pappus. Examples include plants like Clematis, Mirabilis, and Boerhaavia.
• Nut: Single-seeded with a hard pericarp, nuts like cashew and water chestnut (Trapa) fall into this category. In litchi, the pericarp's epicarp and mesocarp fuse, forming a leathery appearance, and the endocarp is thin and membranous. An edible aril surrounds the seed. It is a sort of third integument. In mature fruit, this aril is fleshy and is only edible. 
• Samara: These dry, indehiscent ones are seeded winged/feathery fruit. The wing-like structure develops from the pericarp, which helps in the dispersal of fruits, a prominent characteristic feature of this fruit. Eg., Holoptelea (chil-bil), and Dioscorea. In Shorea robusta, the wing develops from calyx instead of pericarp; these fruits are called samaroid.  

Dehiscent Fruits: The pericarp of these fruits ruptures after ripening, dispersing seeds outside. They come in various types:

• Legume or Pod: Derived from a monocarpellary, unilocular, superior ovary with marginal placentation, legumes are elongated and multi-seeded. They dehisce at both dorsal and ventral sutures, starting from the apex. Examples include peas, beans, and gram.
• Siliqua: Siliqua, a distinctive fruit, originates from a bi-carpellary, syncarpous, superior ovary characterized by parietal placentation. Dehiscence manifests along the dorsal and ventral sutures, commencing from the lower region and progressing towards the apex (base to apex). Initially, the ovary is unilocular, but forming a false septum/replum eventually renders it bilocular. Seeds attach to this false septum. Siliqua fruits are commonly observed within the Cruciferae family, exemplified by Brassica species such as mustard.
• Silicula: Small, broad siliqua is known as silicula. It is a reduced form of siliqua. Eg. Candytuft (Iberis amara), Capsella. 
• Capsule: Fruit developing from syncarpous ovary. Capsules can dehisce through various methods such as poricidal, loculicidal, septifragal, or septicidal. Examples include poppy (Papaver), cotton (Gossypium), datura, ladyfinger (Abelmoschus), and onion.

Schizocarpic Fruits: These fruits split into mericarps upon ripening, each containing one or two seeds. Schizocarpic fruits assemble to be both dehiscent and indehiscent. They include:

• Lomentum: Splitting into one-seeded mericarps, lomentums disperse seeds by separating the mericarps. Examples include tamarind, cassia fistula, and groundnut (Arachis hypogea).
• Cremocarp: In the Umbelliferae family, cremocarps split from apex to base into two mericarps, each containing a seed attached to a carpophore. Examples are coriander, carrot (Daucus), cumin (Cuminum), and fennel (Foeniculum).
• Regma: These fruits feature 3 to 5 locules and split into corresponding one-seeded parts known as cocci. Examples include plants from the Euphorbiaceae family, like castor (Ricinus) and Geranium.
• Carcerulus: Dividing into four one-seeded mericarps without spines, examples of carcerulus fruits include tulsi (Ocimum) and sage (Salvia).

Aggregate Fruits

These fruits develop from a multicarpellary, apocarpous gynoecium. In the apocarpous condition, each carpel is accessible from the others and forms a fruitlet. Aggregate fruits comprise a cluster of fruitlets, known as an etaerio.

• Etaerio of achenes: Each fruitlet is an achene in this type of aggregate fruit. Examples include Ranunculus, strawberry, rose, and lotus. The thalamus becomes spongy in the lotus, and some achenes are embedded. The thalamus is fleshy in strawberries, and small achenes are found on its surface. In roses, many achenes are present on a saucer-like inner surface of the fleshy thalamus. 
• Etaerio of berries: It is an aggregation of small berries. Examples include Polyalthia and Annona squamosa (custard-apple or sitaphal). In the etaerio of Annona, all the berries are densely arranged on the thalamus.
• Etaerio of drupes: In this type of fruit, many small drupes develop from different carpels. Examples include raspberry and blackberry.

Composite Fruits

All composite fruits are false fruits. In composite fruits, the whole inflorescence is generally modified into a fruit. These are of two types:

• Sorosis: This fruit develops from spike, spadix, or catkin inflorescence.

Examples include pineapple (Ananas), jackfruit (kathal), and mulberry (shahtoot).

• Syconus Or Syconium: This fruit develops from a hypanthodium inflorescence. Many achenes develop from the pistillate flowers. 

Examples include Ficus species like fig anjeer( Ficus carica) and peepal (Ficus religiosa).

4.0Multiple Choice Questions(MCQs/NEET)

Q. 1. Geocarpic fruit is:               

• (A)  potato (B)  peanut (C)  onion (D)  garlic

Q.  2. Coconut fruit is a                   

• (A)  Capsule (B)  Drupe (C)  Berry (D)  Nut

Q. 3. Edible part in mango is:         

• (A)  mesocarp (B)  epicarp (C)  endocarp (D)  epidermis

Q. 4. Which of the following represents the edible part of the fruit of litchi?        

• (A) Pericarp (B)  Mesocarp (C)  Juicy aril (D) Endocarp

Q. 5. The fleshy receptacle of syconous of fig encloses a number of                

• (A)  achenes (B)  samaras (C)  berries (D)  mericarps

Q. 6. The fruit is chambered, developed from inferior ovary and has seeds with succulent testa in 

• (A)  pomegranate (B)  orange (C)  guava (D)  cucumber

Q. 7. A fruit developed from hypanthodium inflorescence is called 

• (A)  hesperidium (B)  sorosis (C)  syconus (D)  caryopsis

Q. 8. An aggregate fruit is one which develops from 

• (A)  multicarpellary syncarpous gynoecium
• (B)  multicarpellary apocarpous gynoecium
• (C) complete inflorescence
• (D)  multicarpellary superior ovary
  

Q. 9. Coconut water from a tender coconut is 

• (A)  immature embryo
• (B)  free nuclear liquid endosperm
• (C)  innermost layers of the seed coat
• (D)  degenerated nucellus

Q. 10. Which one of the following fruits is parthenocarpic?         

• (A)  Brinjal (B)  Apple (C)  Jackfruit (D)  Banana

ANSWER KEY

5.0Benefits & Dispersal of Fruits and Seeds

Benefits of fruits(Nutrients & health)

Natural Energy: Fruits provide natural sugars like fructose, which serve as a quick energy source for the body, making them excellent snacks for sustained energy throughout the day.

Antioxidant Properties: Many fruits contain antioxidants such as flavonoids, polyphenols, and vitamin C, which help neutralize harmful free radicals in the body

Rich in Vitamins and Minerals: Fruits are rich in essential vitamins (such as vitamin C, vitamin A, and folate) and minerals (like potassium, magnesium, and calcium), vital for overall health and well-being.

Eye Health: Certain fruits, such as blueberries, carrots, and oranges, contain nutrients like beta-carotene and vitamin C, essential for maintaining good vision and reducing the risk of age-related eye diseases like cataracts and macular degeneration.

High in Dietary Fiber: Most fruits are excellent sources of dietary fiber, which promotes digestive health, prevents constipation, and helps control blood sugar levels.

• Papaya : This tropical fruit papaya is a good source of vitamins A, C and E, which play a role in immunity, skin health and heart health. It also has a lot of fiber, especially if you eat the seeds.

• Watermelon: Watermelon has  92% water, and since food provides about 20% of your fluid intake. Watermelon an extra great hydration helper is that it's also a source of potassium and magnesium, two minerals that function as electrolytes to help balance fluid levels and offset excess sodium in your diet.

• Apples: Evidence has shown that frequent apple consumption may reduce total cholesterol, which can help reduce your risk of heart disease. 

• Pears: Pears are rich in essential antioxidants, plant compounds, and dietary fiber. They are also free from fat and cholesterol. Pears also contain a soluble fiber called pectin, which nourishes gut bacteria and improves gut health.

• Mangoes: Delicious tropical treat filled with vitamin C, potassium- and beta-carotene. The vitamins, minerals, and antioxidants in mangoes can provide important health benefits. For example, vitamin K helps your blood clot effectively and helps prevent anemia. It also plays an important role in strengthening your bones.

• Kiwis: In addition to the vitamin C, potassium and antioxidants a person gets from kiwi, the combination of folate, magnesium and B vitamins.

• Bananas: Bananas are a source of prebiotic fiber, which is necessary for good gut health. Bananas also contain potassium, which supports heart health. 

• Oranges: Citrus fruits have been shown to have anti-inflammatory, antioxidant and anti-cancer properties. 

• Cherries: In addition to their multitude of antioxidant benefits, these little stone fruits contain quercetin, a type of antioxidant linked to promoting feelings of calmness. Vitamin C is an essential nutrient that functions as an antioxidant to "support immunity and help with collagen synthesis for healthy skin and joints.

• Grapes: Grapes contain compounds with antioxidant properties, which may help reduce cellular damage, says London. Frozen grapes are a wonderful, hydrating summer treat.

• Guava: They're rich in vitamin C, potassium and fiber, and have a fair amount of folate. 

• Strawberries: Strawberries are all a great source of antioxidants and fiber. 

• Avocados: Avocado is a unique fruit because of its low sugar content. It also provides heart-healthy fatty acids and magnesium, a key mineral linked to neurological and muscular function. 

• Plums: Plums have been shown to have anti-inflammatory benefits that may help to boost cognition. 

• Raspberries: Raspberries are one of the highest-fiber fruits. Fiber helps stabilize blood sugar levels and keeps you full (especially when combined with a protein).

• Pomegranate: (Punica granatum) The juicy arils of the fruit are eaten fresh, and the juice is used in flavourings and liqueurs. Pomegranate is high in dietary fibre, folic acid, vitamin C, and vitamin K.

• Pineapple: "Pineapple has a compound that others don't called bromelain. It has a potent anti-inflammatory effect, and it also functions as a digestive enzyme to break down protein. It's also loaded with vitamin C and is an excellent source of manganese, a mineral that helps your brain and nervous system function. 

• Figs: Figs are a good source of fiber; they're fairly high in sugar. 

6.0Edible Part of Fruits

7.0Dispersal of Fruits and Seeds

Plants have evolved ingenious methods for dispersing their seeds and fruits to overcome the limitations of growing in close proximity to the parent plant. Wind serves as a primary dispersal agent for lightweight seeds like those of Drumstick and Cinchona, equipped with wings or pappus structures, or those of plants like poppy that utilize fruit dehiscence for seed ejection. Water aids in dispersal for plants such as coconut and lotus, with buoyant fruits or seeds adapted for aquatic transport. Animals, too, play a crucial role, as seeds hitchhike on fur or feathers, or are ingested and later excreted, facilitating dispersal. Examples include Xanthium and Urena fruits with hooks, and edible fruits like guava, dispersed by birds or humans through consumption and subsequent seed dispersion.

Importance of Dispersal of Fruits and Seeds

• It prevents overcrowding & competition for limited resources.
• It allows the plants to have their seeds to land on suitable places for germination, thus increases the chance for the plants to colonize new areas.

Means of Dispersal:

1. Anemochory(By wind )
2. Hydrochory(By water )
3. Zoochory (By animals ) 
4. Autochory(By mechanical force )

Anemochory (dispersal by wind):

• Wind dispersed seeds and fruits have a variety of adaptations which help them to be carried away by wind.
• Light seeds: Seeds of some plants   are sufficiently light and minute in size to easily carry away to great distance by air currents. (E.g. Orchids seeds)
• Wings: Some seeds (Cinchona or Moringa) or fruits (Acer, Terminalia) develop one or more thin membranous wings to ensure their dispersal by wind.
• Censer mechanism: In plants like opium seeds are released in instalment through the pores present near the top of the capsule when the fruit is shaken by strong winds. This process is known as censer mechanism.
• Parachute mechanism: In several plants, fruits or seeds possess different types of  appendages which act like a parachute and help them to be carried by air current to long distances. These appendages are

1. Pappus  :E.g. Helianthus 
2. Coma : E.g. Calotropis.

3. Hairy outgrowth on seeds ; On the cotton seeds
4. Persistent hairy style : On clematis seeds
5. Baloon like appendages : Swollen calyx of Physalis

Zoochory (Dispersal by Animals)

• Hooked fruits, Sticky fruits and seeds Fleshy fruits, Edible fruits

Hydrochory (Dispersal by Water)

• Dispersal of seeds and fruits by water usually occurs in those plants which grow in or near water.  Such seeds and fruits usually develop floating devices in the form of spongy or fibrous outer coats. They are protected from rotting due to the presence of a waxy coating.
• Examples:

1. Lotus  (Nelumbo) : Lotus has spongy thalamus with fruitlets embedded in it.The thalamus floats in water stream.
2. Fruits of coconut and double coconut (Lodoicea) have large fibrous mesocarp which helps them to float long distances in the sea without any injury.

Autochory (Dispersal by Explosive Method)

• Some fruits when ripe burst open with a jerk so that their seeds are thrown apart.
• Common examples:

1. Balsam (Impatiens) : In balsam, mere touch causes the ripe fruit to explode suddenly and seeds are thrown out with a great force.
2. Ruellia : Dry fruits of  Ruellia, when come in contact with water, particularly after a shower of rain, burst suddenly with a noise and scatter the seeds.

3. Squirting cucumber (Ecballium) : Mechanical dispersal of seeds due to build- up of internal pressure occurs in squirting cucumber.

As the fruit mature, tissues around seed is converted into amucilaginous fluid, due to which a high pressure develops inside the fruit.

The tissue around the tip of the stalk breaks and the fruit is detached from the stalk. Due to this viscous substance comes out with seeds as a fountain.

8.0Sample Question on Fruits

Question 1: See picture  given below-

"Is lady finger a fruit?"

Most of them would probably tell you: " NO!"

"Lady's finger is a vegetable! It is not a fruit!"

Sounds like an obvious question but in fact……

Lady finger is actually... a FRUIT too!

WHAT? Lady Finger is a fruit?

WHY?

For science students , need to identify FRUITS in the question.

Strategy for students: Fruit have seeds.. 

Lady finger have seeds, thus it is a fruit. OKk

Let's answer the next question. Is capsicum a fruit?

Look! There's seeds... So capsicum is a FRUIT! OKK