. Explain Briefly the Types of Fruits
TYPES OF FRUITS:
On the basis of the number of ovaries involved, fruits are of following three types: simple fruits, aggregate fruits and composite or multiple fruits.
1. SIMPLE FRUITS
A fruit that develops from a single ovary (either monocarpellary or polycarpellary and syncarpous) of a flower is called simple fruit. Simple fruits are of two types, dry and fleshy.
TYPES OF SIMPLE FRUITS
i. DRY FRUITS
The pericarp becomes more or less dry when ripe. The dry fruits are of three types: Capsular fruits (Dehiscent fruits), Achenial fruit and Schizocarpic fruits.
Capsular fruits: Dehiscent fruits burst automatically on ripening, liberating seeds.
Indehiscent fruits or achenial fruit: Indehiscent fruits do not burst automatically on ripening. Their seeds are discharged after the decay of pericarp.
Schizocarpic fruits: Schizocarpic fruits split into a number of indehiscent units called mericarps. But when the broken piece gets dehisced, it is called coccus. Each mericarp contains one seed. However, the pericarp does not burst and seed is liberated only after the decomposition of pericarp. Thus these are intermediate between dehiscent and indehiscent types.
2. FLESHY FRUITS
Fruits in which the entire pericarp or a part of it and/or accessory structures associated with it become fleshy and juicy at maturity.
Types of Fleshy Fruits:
i. Drupe (stone fruits): It is one or more seeded fleshy fruit developing from a mono or polycarpellary, syncarpous and superior ovary. The pericarp of drupe consists of a thin epicarp (forms the skin), a fleshy mesocarp (forms the edible part) and hard and stony endocarp. The name stone fruit is given to them due to stony endocarp. Prunus amygdalis (almond), Cocos nucifera (coconut), Prunus persica (peach), Mangifera indica (mango), Trapa bispinosa (water chestnut), etc.
ii. In coconut, the mesocarp is fibrous (not fleshy as in other drupes) and the edible part is the endosperm of seed.
iii. Berry: It is one or many seeded fleshy fruit developing usually from a bicarpellary or polycarpellary, syncarpous and superior or inferior ovary. In berries the seeds are attached to the placenta in the begining but at maturity they are found loose in the pulp.
iv. The pericarp of berries is differentiated into epicarp, mesocarp and endocarp (like drupes) but here the endocarp is not stony as in drupes. The endocarp becomes thin, mucilaginous and gets broken into pieces, each piece surrounding a seed, e.g.. Lycopersicum esculentum (tomato) Vitis vinifera (grapes), Musa paradisica (banana), Carica papaya (papaya), Phoenix dactylifera (date plant), Capsicum annum (chilli), Areca catechu (betel or arecanut), Psidium guayava, etc.
v. Pome: It is a fleshy fruit surrounded by the thalamus. It develops from bicarpellary, syncarpous, inferior ovary. In pome the edible part is thalamus whereas the true fruit remains embedded, e.g., Pyrus malus (apple), Malus pumila (pear), etc.
vi. Pepo: Like berry, pepo is also a many seeded fleshy fruit but it develops from a tricarpellary, syncarpous, unilocular, inferior ovary with parietal placentation. Although the seeds in pepo are embedded in the pulp but unlike berry they remain attached to the placenta. It is a characteristic fruit of the family Cucurbitaceae, e.g., Lagenaria siceraria (bottle gourd), Citrullus lanatus (water melon), Cucumis sativus (cucumber), etc.
vii. Hesperidium: It is many chambered fleshy fruit developing from a polycarpellary, syncarpous, multilocular, superior ovary bearing seeds on axile placentation. The leathery epicarp of hesperidium has many glands of aromatic oil. The mesocarp, represented by white fibres is fused to the epicarp. The epicarp and mesocarp together form the rind. The endocarp is thin and papery. It projects inwards and forms many compartments. The inner wall of endocarp gives out many juicy succulent hairs, which form the edible part of the fruit. Hesperidum is a characteristic fruit of the family Rutaceae, e.g., Citrus aurantifolia (lemon), Citrus reticulata (oranges), etc.
viii. Balausta: This is many chambered, many seeded fruit developing from a polycarpellary, syncarpous but inferior ovary. The pericarp of balausta is leathery or tough. The carpels are arranged in two rows. Calyx is persistent. The seeds have succulent seed coat (testa), which forms the edible part, e.g., Punica granatum (Pomegranate).
ix. Amphisarca: It is many seeded fleshy fruit with a stony pericarp. It develops from a polycarpellary, syncarpous, superior ovary. The edible part of the fruit is the inner fleshy layer of pericarp and the placenta e.g., Aegle marmelos, (wood apple), Feronia limonia, etc.
i. Fruits developed from a flower having a number of free (apocarpous) carpels, all of which ripe together and are aggregated as a unit on a common receptacle are known as aggregate fruits. Thus, each fruitlet of an aggregate fruit represents a single ovary of an apocarpous pistil.
ii. The fruitlets of a group are collectively termed as etaerio. In an etaerio, fruitlets may be follicles, achenes, drupe or berries.
iii. Etaerio of follicles: It consists of number of follicles clustered together on a pedicle. It is found in Calotropis, Catheranthus roseus and Aconitum
iv. Etaerio of achenes: It is an aggregate of achenes clustered together on a common thalamus e.g., rose, strawberry, Clematis and lotus.
v. Etaerio of drupes: In this type of fruit, many small drupes, developed from different carpels are arranged collectively on the fleshy thalamus, e.g., Raspberry (Rubus idaeus).
vi. Etaerio of berries: It is an aggregate fruit of small berries. Apical part of berries fuses with each other and makes a common rind, e.g., Polyalthea, Anona squamosa (custard apple).
3. MULTIPLE OR COMPOSITE FRUITS
i. These fruits being complex fruits develop from the whole inflorescence. Such fruits are of two types:
ii. Sorosis: It develops from spike or spadix inflorescence. Here the flowers fuse by their succulent petals and axis bearing the flowers becomes fleshy or woody, thus forming a compact mass e.g., Ananas sativus (pineapple), Artocarpous integrifolia (jackfruit) and Morus indica (mulberry).
iii. Syconous: It develops from hypanthodium inflorescence. A characteristic feature of syconus is a hollow or pear shaped fleshy receptacle which forms the edible part of the fruit, e.g., Ficus carica (fig), Ficus benghalensis (banyan), Ficus religiosa (peepal), etc.