NCERT Chapter Exercises
1. How is a pinnately compound leaf different from a palmately compound leaf?
- Pinnately Compound Leaf: A number of leaflets are present on a common axis called the rachis, which represents the midrib of the leaf (e.g., Neem).
- Palmately Compound Leaf: The leaflets are attached at a common point, i.e., at the tip of the petiole, resembling the fingers of a palm (e.g., Silk cotton).
2. Explain with suitable examples the different types of phyllotaxy.
Phyllotaxy is the pattern of arrangement of leaves on the stem or branch. It is of three types:
- Alternate: A single leaf arises at each node in an alternate manner. Examples: China rose, Mustard, Sunflower.
- Opposite: A pair of leaves arise at each node and lie opposite to each other. Examples: Calotropis, Guava.
- Whorled: More than two leaves arise at a node and form a whorl. Example: Alstonia.
3. Define the following terms:
- (a) Aestivation: The mode of arrangement of sepals or petals in a floral bud with respect to other members of the same whorl.
- (b) Placentation: The arrangement of ovules within the ovary.
- (c) Actinomorphic: Radial symmetry in flowers; when a flower can be divided into two equal radial halves in any radial plane passing through the centre.
- (d) Zygomorphic: Bilateral symmetry; when a flower can be divided into two similar halves only in one particular vertical plane.
- (e) Superior Ovary: When the gynoecium occupies the highest position while other parts are situated below it (Hypogynous flower).
- (f) Perigynous Flower: When the gynoecium is situated in the centre and other parts are located on the rim of the thalamus almost at the same level.
- (g) Epipetalous Stamen: When stamens are attached to the petals (e.g., Brinjal).
4. Differentiate between:
(a) Racemose and Cymose inflorescence
- Racemose: The main axis continues to grow; flowers are borne laterally in an acropetal succession.
- Cymose: The main axis terminates in a flower, hence growth is limited; flowers are borne in a basipetal order.
- Apocarpous: Carpels are free from each other (e.g., Lotus, Rose).
- Syncarpous: Carpels are fused together (e.g., Mustard, Tomato).
5. Draw the labelled diagram of the following:
(i) Gram seed
[Diagram should show: Seed coat, Hilum, Micropyle, and internally: two fleshy Cotyledons, Plumule, and Radicle.]
(ii) V.S. of maize seed
[Diagram should show: Fused Seed coat/fruit wall, Endosperm, Aleurone layer, Scutellum (cotyledon), Coleoptile, Plumule, Radicle, and Coleorhiza.]
6. Take one flower of the family Solanaceae and write its semi-technical description. Also draw their floral diagram.
Example: Solanum nigrum (Makoi)
- Flower: Bisexual, actinomorphic.
- Calyx: Sepals five, united, persistent, valvate aestivation.
- Corolla: Petals five, united, valvate aestivation.
- Androecium: Stamens five, epipetalous.
- Gynoecium: Bicarpellary, syncarpous; ovary superior, bilocular, placenta swollen with many ovules.
- Floral Formula: ⊕ ⚥ K(5) C(5) A5 G(2)
[Floral Diagram showing 5 united sepals, 5 united petals, 5 epipetalous stamens, and a superior bilocular ovary.]
7. Describe the various types of placentations found in flowering plants.
- Marginal: Placenta forms a ridge along the ventral suture of the ovary (e.g., Pea).
- Axile: Placenta is axial and ovules are attached to it in a multilocular ovary (e.g., China rose, Tomato).
- Parietal: Ovules develop on the inner wall of the ovary (e.g., Mustard).
- Free Central: Ovules are borne on central axis and septa are absent (e.g., Dianthus).
- Basal: Placenta develops at the base of ovary and a single ovule is attached to it (e.g., Sunflower).
8. What is a flower? Describe the parts of a typical angiosperm flower.
A flower is the reproductive unit in angiosperms meant for sexual reproduction. It consists of four whorls:
- Calyx: Outermost whorl, consists of sepals (green, leaf-like).
- Corolla: Second whorl, consists of petals (brightly coloured to attract pollinators).
- Androecium: Male reproductive organ, consists of stamens (stalk/filament and anther).
- Gynoecium: Female reproductive organ, consists of carpels (stigma, style, and ovary).
9. Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.
Inflorescence: The arrangement of flowers on the floral axis.
The basis for classification is whether the apex gets developed into a flower or continues to grow:
The basis for classification is whether the apex gets developed into a flower or continues to grow:
- Racemose: The main axis continues growth; younger flowers are at the top (acropetal).
- Cymose: The main axis terminates in a flower; younger flowers are at the base (basipetal).
10. Describe the arrangement of floral members in relation to their insertion on thalamus.
Based on the position of calyx, corolla, and androecium in respect of the ovary on the thalamus:
- Hypogynous: Gynoecium occupies the highest position; ovary is superior (e.g., Mustard).
- Perigynous: Gynoecium is in the centre and other parts are on the rim of the thalamus; ovary is half inferior (e.g., Rose).
- Epigynous: Margin of thalamus grows upward enclosing the ovary completely; ovary is inferior (e.g., Guava, Cucumber).