BIOLOGY PRACTICAL ON AN ORANGE AND A TOMATO FRUIT.
BIOLOGY PRACTICAL ON AN ORANGE AND A TOMATO FRUIT.
ORANGE FRUIT
An orange fruit is a true fruit formed from only the ovary of the flower and is a simple fruit.
It is also a Berry
Reasons:
- Has a thin outer epicarp
- Fleshy mesocarp
- Fleshy inner endocarp
- Numerous seeds.
Observable features
- Bright colour of epicarp
- Succulent mesocarp
- Fleshy endocarp
- Seeds
- Placenta
- Multilocular (several chambers or partitions)
- Remains of style and (or point of attachment).
NB:
- If transversely sectioned, then only one scar.
- If longitudinally sectioned or whole fruit, then two scars
Based on the observable features suggested above, the flower that forms the fruit is a;
- Syncarpous flower with a Superior ovary
Food nutrients/classes of food in an orange fruit
- Vitamin C
- Glucose
- Water
- Mineral salts
- Dietary fibre
Economic importance of an orange fruit
- Source of Food/Vitamin C
- Source of Employment
- Source of income
- Source of Raw material for industries
Iodine test on an orange fruit
- A drop of iodine solution on the cut surface of an orange fruit
- Juice does not produce a blue-black colour,
- Indicating starch is absent in the fruit
Functions of vitamin C
- Formation of connective tissue
- It helps to heal wounds
- Production of strong skin
- Collagen fibre synthesis
- Prevents infections
Deficiency of vitamin C
- Scurvy
Symptoms of scurvy
- Bleeding gums/sore mouth
- Wounds fail to heal
- Reduced resistance to infections
- Weakness of muscles/the body
- Anaemia
- Loosening of teeth
- Swelling of joints/gums
Other sources of vitamin C
- Raw leafy vegetables,
- Green vegetables,
- Potatoes,
- Tomatoes
Functions of water in animals
- Aids digestion of food
- Transports excretory products for elimination
- As a universal solvent, it is a medium in which chemical reactions occur
- Transports nutrients in the body
- Temperature regulation by sweating
- As a lubricant in joints (synovial fluid)
- Osmoregulation/Osmotic balance
- Hydrostatic skeleton, e.g. earthworm
- As a major component of protoplasm in all living things
General Functions of Minerals
- Metabolic activities
- Structure of tissue
Functions of Dietary fibre in humans
- Source of vitamin K
- Aids digestion
- Prevents constipation
Agent of dispersal:
- Animals
Reasons:
- Brightly Coloured epicarp attracts animals
- Sweet scented
- Succulent hairs in the mesocarp serve as food for animals
Examples of animals that disperse orange
- Birds
- Humans
- Monkeys
- Bats
Adaptations of orange fruit to its mode of dispersal.
- The coloured epicarp attracts animals
- Sweet scent attracts animals
- Succulent mesocarp as food for animals
- Seeds with hard testa to resist digestion when swallowed
- Sticky seeds stick to the beak of large birds
Describe how an orange fruit is dispersed
- It is dispersed by animals.
- It is a succulent fruit and the right colour of epicarp with Succulent inner part(s)
- Attract animals
- Animals may carry the fruit away
- Some seeds may be swallowed but have a hard testa, which escapes digestion in the alimentary canals of birds and comes out with faeces.
- Some seeds may fall on the ground while feeding on the fruit
- Some seeds are very sticky and adhere to the beak of birds and get dispersed when the birds clean their beak elsewhere
- Thereby bringing about dispersal
TOMATO FRUIT
Classification:
- Berry
Reasons:
- Fruit formed from a syncarpous ovary
- Has a thin outer epicarp,
- Fleshy inner endocarp
- Fleshy mesocarp
- Numerous seeds
Placentation:
- Axile
Tomato fruit is a True fruit
Reason:
- It is developed from the fertilised ovary only.
It is a Simple fruit
Reason:
- This is formed from a single several fused carpels/pistils.
- Formed from a syncarpous ovary
It is also a Fleshy fruit
Reason:
- Pericarp does not dry at maturity
Classes of food in tomato:
- Vitamins,
- Mineral salts
- Water
- Carbohydrates
lodine test on tomato fruit
- A drop of iodine solution on a cut surface of tomato fruit or tomato fruit juice does not produce a blue-black colour,
- Indicating starch is absent in the fruit
Preservation of tomato fruits
- Freezing
- Irradiation
- Canning
Agents of dispersal of tomato
- Animals
Reasons:
- Brightly coloured (bright red) epicarp attracts animals
- Succulent and fleshy mesocarp to attract animals
- Seeds have a hard testa which resists digestion and passes out with faeces
Animals that disperse tomato
- Birds
- Human
Observable features
- Bright colour of epicarp
- Smooth epicarp
- Succulent mesocarp
- Fleshy endocarp
- Seeds
- Placenta
- Multilocular (several chambers/partitions)
- Remains of style and or point of attachment
Dispersal of Tomato
- Dispersed by birds
- Coloured epicarp, juicy and sweet-scented mesocarp attract birds.
- To feed on the fruit
- The fruit may be carried away by animals/birds
- Small seeds are swallowed as birds feed.
- Hard and slimy testa resists digestion by enzymes in the alimentary canal of birds.
- Undigested seeds are deposited with faeces
- Some seeds may fall on the ground while feeding on the fruit
- Some seeds are very sticky and adhere to the beak of birds and get dispersed when the birds clean their beak elsewhere, and the seeds germinate there
- thereby bringing about dispersal
Similarities between the transverse sections of orange and tomato fruits
- Presence of fused epicarp and mesocarp
- Presence of succulent endocarp
- Axile placentation
- Presence of seeds
- Brightly coloured epicarp.
Observable differences between cross sections of orange fruit and tomato fruit.
| ORANGE FRUIT | TOMATO FRUIT |
| Large seeds | Smaller seeds |
| Few seeds | Many seeds |
| Presence of yellowish epicarp | Epicarp is bright red |
| Hard epicarp and mesocarp. | Soft epicarp and mesocarp. |
| Smaller placenta | Large placenta |
| Rough epicarp | Smooth epicarp |
| Thick epicarp | Thin epicarp |
