PBOT111 FRUITS, SEEDS and GERMINATION

FRUIT

• The ripened ovary of the flower

FRUIT

• Protects seeds, aid in their dissemination, and may be factor in timing their germination

PERICARP

• Fruit wall

Exocarp

• outermost layer of pericarp

mesocarp

• fleshy middle layer of pericarp

endocarp

innermost layer which usually surrounds the seed

Normal

fruit that develops after fertilization

Parthenocarpic

fruit that develops without fertilization

Simple fruit

develops from 1 ovary

Compound fruit

develops from several ovary

Aggregate

Develops from the several,ovaries of a single flower

Multiple (Collective)

• Develops from several ovaries of a compact inflorescence

• langka, durian, rimas, pineapple

Example of Multiple (Collective)

Legume or Pod 

arises from a single carpel which at,maturity splits along 2 sutures; with the shell, pericarp endorsing the seeds

• peanut, sitao, batao, patani

Examples of Legume or Pod 

Follicle

• develops from a single carpel and opens along 1 suture 

camachille and kalachuchi

Example of Follicle

Capsule

• derives from an ovary with 2 or more united carpels, each carpel producing few to many seeds and splits in various ways

• castor oil, banaba, okra and cotton

Example of Capsule

Silique

derives from a superior ovary consisting of 2 locules which at maturity, separates into 3 portions with the seeds attached to the central, persistent portion

malunggay

Example of Silique

Achene

• commonly called “seeds” but when the pericarp is broken, the seeds within is seen to be attached to the ovary wall at one point 

strawberry, pineapple

Example of Achene

Grain (Caryopsis) 

like the achene, it is also one seeded, but the pericarp and seed coat are firmly united

corn, rice

Example of Grain (Caryopsis) 

Samara

may be one-seeded or two- seeded and has a wing like outgrowth of the ovary wall

• narra, maple

Examples of Samara

Nut

• one-seeded fruit with a hard or stony pericarp commonly called the shell

• carrot, mustard family

Examples of Schizocarp

Schizocarp

• derived from 2 carpels which splits when mature, along the midline into 2 one-seeded indehiscent leaves

• cashew nut, pistachio, wall nut, chestnut

Examples of Nut

Berry

derived from a compound ovary, usually many seeds are embedded in a fleshy part which is both endocarp and mesocarp

• eggplant, tomato, grapes

Examples of Berry

Hesperidium

• type of berry, with a thick leathery rind with numerous glands which constitute the exocarp and mesocarp and a thick juicy portion of several wedge-shaped locules which are outgrowths from the endocarp

• orange, pomelo, calamansi, dalandan

Examples of Hesperidium

Pepo

• berry-like fruit with a hard rind derived from the fusionof the receptacle and the exocarp while the fleshy part of the fruit is principally mesocarpand endocarp

• cucumber, squash and watermelon

Examples of Pepo

Drupe

• derived from one carpel and is usually one-seeded, exocarp is thin, mesocarp maybe fleshy of fibrous and the endocarp is hard, consisting of thick- walled stone cells

• pili nut, coconut, mango, avocado

Examples of Drupe

Pome

• derived from an inferior ovary; the fleshy part is the enlarged floral tube and the core comes from the ovary

• apple, pear

Examples of Pome

Seed coats

• The covering of a seed

Seed coats

• Made up of the testa derived from the outer integument and the tegmen from the inner integument

Hilum

scar on the seed coat

Micropyle

small opening near the hilum

Raphe

ridge located on the testa

Endosperm

• Derives from the primary endosperm cell and contains the stored food of the seed

Embryo

The young plant inside the seed

Cotyledon

one or two seeded leaves

Epicotyl

part of the embryo above the point of attachment of the cotyledons; its growing tip, the plumule, constitutes the first bud

Hypocotyl

part of the embryo below the point of attachment of the cotyledons; its growing tip, the radicle give rise to the primary root

Non-endospermic seeds (exalbuminous seeds)

• Endosperm is absent

Dicotyledonous seeds

• With 2 cotyledons

Monocotyledonous seeds

• With 1 cotyledons

DISSEMINATION

• The transfer of fruits and seeds to distant places

AGENTS FOR DISPERSAL: WIND

• Seeds and fruits dispersed by wind are generally light and may have some structural adaptations like wings and plumes

AGENTS FOR DISPERSAL: WIND

• Some are simply dispersed by the violent splitting of the pericarp

AGENTS FOR DISPERSAL: ANIMALS

• Seeds and fruits dispersed by animals have spines or barbs that adhere to animal fur

AGENTS FOR DISPERSAL: ANIMALS

• Seeds of many fruits pass through the digestive tract without being digested and are still viable when egested

AGENTS FOR DISPERSAL: ANIMALS

• Seeds may be sticky and carried on the feet of some birds

AGENTS FOR DISPERSAL: WATER

• Fruits dispersed by water are buoyant

Germination

• Is the beginning of the growth of the seed, spore, bud, or other structures

Steps in Germination

1. Seeds takes up water and swells

2. Food is digested

3. Respiration increases

4. Cell division occurs

5. Embryo grows

6. Seed coat ruptures

Hypocotyl

is usually the first part of the embryo to emerge from the seed coat, followed by the epicotyl

Seedling

A sprouted embryo is called

EXTERNAL CONDITIONS

Moisture

EXTERNAL CONDITIONS

Oxygen

EXTERNAL CONDITIONS

Temperature – optimal is bet. 25°C to 30°C

EXTERNAL CONDITIONS

Food supply

EXTERNAL CONDITIONS

Others – light, soil, acidity, CO2, etc

INTERNAL CONDITIONS

Auxins or growth regulators

INTERNAL CONDITIONS

Stored foods in the seeds