Reproductive Morphology Exercise Solutions | KalviGavani

How to Use This Page

Solve each Samacheer Kalvi exercise question on your own first, then compare your answer with the solutions below. Reproductive Morphology covers flower structure, inflorescence types, fruit and seed — focus on identifying parts and their functions.

Key Concepts (Quick Recap)

Flower Structure

A typical flower has four whorls arranged on the thalamus:

1. Calyx (Sepals): Outermost whorl, green, protects the flower bud 2. Corolla (Petals): Second whorl, brightly coloured, attracts pollinators 3. Androecium (Stamens): Male reproductive whorl — each stamen has filament + anther 4. Gynoecium (Pistil/Carpel): Female reproductive whorl — each pistil has stigma + style + ovary

Types of Flowers

Aestivation (arrangement of petals/sepals in bud)

• Valvate: Margins touch but don't overlap — e.g., Calotropis
• Twisted: Margins overlap in one direction — e.g., Hibiscus, Cotton
• Imbricate: Margins overlap irregularly — e.g., Cassia, Gulmohar
• Vexillary (Papilionaceous): Largest petal (standard) overlaps the wings — e.g., Pea, Bean

Placentation (arrangement of ovules in ovary)

• Marginal: Ovules along the ventral suture — e.g., Pea, Bean
• Axile: Ovules on the central axis in a multilocular ovary — e.g., Tomato, Lily
• Parietal: Ovules on the inner wall of the ovary — e.g., Mustard, Argemone
• Basal: Single ovule at the base — e.g., Sunflower, Marigold
• Free central: Ovules on the central axis without septa — e.g., Dianthus, Primrose

Inflorescence Types

• Racemose: Main axis grows indefinitely; flowers in acropetal order
• Raceme, Spike, Catkin, Spadix, Corymb, Umbel, Capitulum (head)
• Cymose: Main axis terminates in a flower; flowers in basipetal order
• Uniparous cyme, Biparous cyme, Multiparous cyme
• Special types: Cyathium (Euphorbia), Verticillaster (Ocimum), Hypanthodium (Fig)

Fruit Types

• True fruit: Develops only from the ovary — e.g., Mango, Tomato
• False fruit (Pseudocarp): Develops from parts other than ovary — e.g., Apple (thalamus), Strawberry (thalamus)
• Simple fleshy fruits: Drupe (mango), Berry (tomato, banana), Pome (apple)
• Simple dry fruits: Achene (sunflower), Caryopsis (wheat), Cypsela (marigold), Legume (pea), Capsule (cotton)

Seed Structure

Dicot Seed (e.g., Bean):

• Seed coat: Testa (outer) + Tegmen (inner)
• Hilum: Scar where seed was attached to fruit
• Micropyle: Small pore for water absorption
• Embryo: Two cotyledons + Plumule (shoot) + Radicle (root)
• Endosperm: Present (albuminous) or absent (exalbuminous)

Monocot Seed (e.g., Maize):

• Seed coat: Fused with fruit wall (pericarp)
• Endosperm: Large, starchy (albuminous)
• Embryo: One cotyledon (scutellum) + Plumule + Radicle
• Aleurone layer: Protein-rich outer layer of endosperm

I. Choose the Best Answer (MCQs)

Q1. The outermost whorl of a flower is called (a) Corolla (b) Androecium (c) Calyx (d) Gynoecium

Q2. A flower having both stamens and pistil is called (a) Staminate (b) Pistillate (c) Bisexual (d) Neuter

Q3. In racemose inflorescence, the main axis (a) Terminates in a flower (b) Grows indefinitely (c) Grows from the centre (d) Branches repeatedly

Q4. Apple is a (a) True fruit (b) False fruit (c) Aggregate fruit (d) Multiple fruit

Q5. The plumule of a seed develops into (a) Root (b) Stem (c) Leaf (d) Fruit

II. Fill in the Blanks

1. The four whorls of a flower are calyx, corolla, androecium, and gynoecium. 2. The male reproductive part of a flower is the androecium (stamen). 3. The female reproductive part of a flower is the gynoecium (pistil/carpel). 4. A flower with all four whorls is called a complete flower. 5. A flower with only stamens or only pistil is called a unisexual flower. 6. In racemose inflorescence, flowers are arranged in acropetal order. 7. In cymose inflorescence, flowers are arranged in basipetal order. 8. A true fruit develops from the ovary. 9. A false fruit develops from parts other than the ovary, such as the thalamus. 10. The seed coat has two layers: outer testa and inner tegmen. 11. The scar on the seed where it was attached to the fruit is called the hilum. 12. The small pore on the seed for water absorption is the micropyle. 13. The embryonic root is called the radicle. 14. The embryonic shoot is called the plumule. 15. Dicot seeds have two cotyledons; monocot seeds have one cotyledon.

III. True or False (with corrections for false statements)

IV. Match the Following

V. Answer Briefly (2-mark questions)

VI. Answer in Detail (5-mark questions)

Common Mistakes to Avoid

• Confusing racemose and cymose: Racemose = indefinite growth, acropetal order. Cymose = definite growth (terminates in flower), basipetal order.
• Calling apple a true fruit: Apple is a FALSE fruit. The edible part is the thalamus, not the ovary.
• Confusing staminate and pistillate: Staminate = only stamens (male). Pistillate = only pistils (female).
• Confusing placentation types: Marginal = ovules on the margin (pea). Axile = ovules on central axis (tomato). Parietal = ovules on inner wall (mustard). Learn with examples.
• Confusing cotyledons in dicots vs monocots: Dicots have TWO cotyledons. Monocots have ONE cotyledon (scutellum).
• Forgetting that monocot seed coat is fused with fruit wall: In monocots (like maize), the seed coat is fused with the pericarp. In dicots, they are separate.

Exam Checklist

• [ ] Can you name and describe all four whorls of a flower?
• [ ] Can you distinguish between complete and incomplete, bisexual and unisexual flowers?
• [ ] Can you explain actinomorphic and zygomorphic symmetry?
• [ ] Can you describe the types of aestivation with examples?
• [ ] Can you describe the types of placentation with examples?
• [ ] Can you distinguish between racemose and cymose inflorescence?
• [ ] Can you distinguish between true fruit and false fruit?
• [ ] Can you describe the structure of a dicot seed and a monocot seed?
• [ ] Can you explain placentation, aestivation, and phyllotaxy with examples?
• [ ] Can you compare dicot seed and monocot seed (at least 6 points)?