Q: List the changes observed in angiosperm flower subsequent to pollination and fertilisation. (4 Marks)
A: 1. Calyx and Corolla - Fall down
2. Stamens and style - Bend down
3. Ovary - Fruit
4. Ovary wall - Pericarp
5. Ovules - Seeds
6. Integuments - Seed coats
7. Zygote - Embryo
8. Primary Endosperm cell - Endosperm
9. Remaining nucellus - Perisperm
10. Stalk of the flower - Stalk of the fruit
Q: Describe any four types of placentation found in flowering plants. (4 Marks)
A: Placentation: The arrangement of ovules attached to the placenta in the ovary is called placentation.
It can be observed if a transverse section of the ovary is seen and seen under microscope. It is 5 types.
1. Marginal Placentation: Ovules are arranged in 2 rows on the long ridge like placenta formed by the union of 2 long margins of a carpel on ventral side.
It is the characteristic feature of Fabaceae. Ex: Bean.
2. Axile Placentation: Ovules are attached to the placenta formed in the centre of the ovary with not less than 2 locules. Ex: Hibiscus, Castor, Datura, Citrus.
3. Parietal Placentation: Ovules are attached to the placenta formed on the periphery or on the inner wall of the ovary (unilocular Ex: Cucurbits or bilocular). Ex: Mustard, Argemone.
4. Free Central Placentation: Ovules are attached to the placenta in the centre of the unilocular ovary which is actually derived from multi locular ovary due to the dissolution of septa.
Ex: Dianthus, Primrose.
5. Basal Placentation: Single ovule is attached to the placenta formed at the base of unilocular ovary. Ex: Helianthus, Tagetus (Marigold).
Q: Describe in fleshy fruits you studied? (4 M)
A: The fruits in which pericarp is divisible into epicarp, mesocarp and endocarp are called fleshy fruits. The simple, fleshy fruits are divided into 5 types.
1. Berry: It is a simple fleshy superior (Brinjal, Tomato, Grapes) or inferior (Guava, Banana) fruit developing from bi or multicarpellary syncarpous gynoecium.
Its characteristic feature: Mesocary fuses with endocarp and forms pulp which encloses hard seeds.
2. Pepo: It is a simple, fleshy inferior fruit developing from tricarpellary syncarpous, unilocular ovary. Ex: Cucumber (Cucurbita ceae).
Its characteristic feature: Thalamus fuses with epicarp to form rind. Mesocarp (fleshy), endocarp (smooth) and placenta are edible.
3. Hesperidium: It is a simple, superior fruit developing from multicarpellary, synearpous multilocular,
ovary. Ex: Citrus (Rutaceae).
Its characteristic feature: Epicarp is glandular, mesocarp is papery and endocarp with juicy, sugary
hairs is edible.
4. Pome: It is a simple, fleshy, false, inferior fruit developing from bi or multicarpellary synearpous gynoecium.
Its characteristic feature: Thalamus is fleshy edible and endocarp is Cartilagenous. Ex: Apple.
5. Drupe: It is a superior single seeded fleshy fruit developing from monocarpellary, unilocular ovary. Ex: Coconut, Mango. Its characteric feature: Endocarp is stony.
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