આ MCQ મોડ્યુલ આના પર આધારિત છે: NCERT Exercises and Solutions: Anatomy of Flowering Plants
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NCERT Exercises and Solutions: Anatomy of Flowering Plants
🎓 Class 11
Biology
CBSE
Theory
Ch 6 – Anatomy of Flowering Plants
⏱ ~8 min
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આ મૂલ્યાંકન આના પર આધારિત હશે: NCERT Exercises and Solutions: Anatomy of Flowering Plants
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NCERT Exercises and Solutions: Anatomy of Flowering Plants
Chapter 6 Summary
Plant tissues are broadly classified into two — meristematic (actively dividing) and permanent (differentiated). Meristems are at apex (apical), between mature tissues (intercalary), and along the sides (lateral). Apical and intercalary are primary; lateral meristems contribute to secondary growth.
Permanent tissues are simple (parenchyma — living, thin walls, storage/photosynthesis; collenchyma — living, thick at corners, flexible support; sclerenchyma — dead, lignified, rigid support) or complex (xylem — water transport, with tracheids, vessels, fibres, parenchyma; phloem — food transport, with sieve tubes, companion cells, parenchyma, fibres).
Tissues are organised into three tissue systems — epidermal (epidermis with stomata, trichomes), ground (cortex, pith, medullary rays), and vascular (xylem + phloem). Vascular bundles are radial in roots, conjoint in stems and leaves; open with cambium in dicots, closed in monocots.
The internal structure of dicot vs monocot organs differs: roots (dicot tetrarch with small/no pith vs monocot polyarch with large pith); stems (dicot bundles in a ring with cambium vs monocot bundles scattered, no cambium); leaves (dicot dorsiventral with palisade + spongy mesophyll vs monocot isobilateral with uniform mesophyll, bulliform cells).
Secondary growth in dicots involves vascular cambium (forms secondary xylem inside, secondary phloem outside) and cork cambium (forms periderm — phellem outside, phelloderm inside). Annual rings (spring wood + autumn wood) record age. Heartwood (dead, dark, supportive) and sapwood (living, light, conducting) form the secondary xylem mass. Lenticels in cork allow gas exchange.
Key Terms
Casparian strip, Pericycle, Conjunctive tissue, Suberin, Trichome
NCERT Exercises
Q1. State the location and function of different types of meristem.
| Meristem | Location | Function |
|---|---|---|
| Apical | Tips of root and shoot | Primary growth — increases length |
| Intercalary | Between mature tissues, often at the base of internodes/leaves (grasses) | Internode elongation; regrowth after grazing |
| Lateral | Cylinders along sides — vascular cambium, cork cambium | Secondary growth — increases girth |
Q2. Cork cambium forms tissues that form the cork. Do you agree with this statement? Explain.
Yes, partly. Cork cambium (phellogen) cuts off cells on BOTH sides:
- Outwards: Forms cork (phellem) — dead, suberised, water-impermeable cells.
- Inwards: Forms secondary cortex (phelloderm) — living parenchyma cells.
Q3. Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?
Steps of secondary growth:
- Cambial ring formation: Fascicular cambium (between xylem & phloem of each bundle) connects with interfascicular cambium (formed by dedifferentiation of medullary rays) → continuous cambial ring.
- Cambial activity: The cambium cuts off cells on both sides — secondary xylem (inwards, towards pith) and secondary phloem (outwards, towards periphery).
- Annual rings: In temperate areas — spring wood (lighter, wider vessels) + autumn wood (darker, narrow vessels) = one annual ring/year.
- Heartwood + sapwood differentiation: Older central xylem becomes heartwood (dead, dark, full of resins/tannins, only mechanical support); outer xylem stays as sapwood (light, conducting).
- Cork cambium: Develops in cortex; cuts off cork (phellem) outside and secondary cortex (phelloderm) inside. Together with phellogen = periderm.
- Lenticels: Pores in cork for gas exchange.
- Increases girth and provides additional mechanical support to bear the weight of branches/leaves.
- Replaces old conducting tissue with new vascular elements — keeps trees alive for decades/centuries.
- Periderm protects against water loss, pathogens, and physical injury.
- Heartwood gives commercial timber its hardness and decay-resistance.
Q4. Draw illustrations to bring out the anatomical difference between (a) Monocot root and Dicot root (b) Monocot stem and Dicot stem.
(a) Monocot root vs Dicot root:
(b) Monocot stem vs Dicot stem:
[See Figs 6.6, 6.7, 6.8 in Part 3 for diagrams.]
| Feature | Dicot Root | Monocot Root |
|---|---|---|
| Xylem patches | 2–4 (di/tri/tetrarch) | Many (polyarch, 8–12+) |
| Pith | Small or absent | Large, well developed |
| Conjunctive tissue | Parenchymatous (becomes cambium) | Sclerenchymatous |
| Secondary growth | Present | Absent |
| Feature | Dicot Stem | Monocot Stem |
|---|---|---|
| Hypodermis | Collenchymatous | Sclerenchymatous |
| Vascular bundle arrangement | In a ring | Scattered |
| Cambium | Present (open bundle) | Absent (closed bundle) |
| Pith | Distinct, large | Not distinct (replaced by ground tissue) |
| Medullary rays | Present | Absent |
Q5. Cut a transverse section of young stem of a plant from your school garden and observe it under the microscope. How would you ascertain whether it is from a dicot or monocot plant? Give reasons.
Step-by-step diagnosis:
- Look at vascular bundle arrangement: If scattered through ground tissue → MONOCOT. If arranged in a ring → DICOT.
- Check for cambium in vascular bundle: Strip of meristematic cells between xylem and phloem present → DICOT. Absent → MONOCOT.
- Check pith: Distinct large pith in the centre → DICOT. No clear pith (ground tissue uniform) → MONOCOT.
- Check hypodermis: Collenchymatous (cells with corner thickening) → DICOT. Sclerenchymatous (lignified, dead) → MONOCOT.
- Look for medullary rays: Present in dicots; absent in monocots.
Q6. The transverse section of a plant material shows the following anatomical features: (a) the vascular bundles are conjoint, scattered and surrounded by a sclerenchymatous bundle sheaths. (b) phloem parenchyma is absent. What will you identify it as?
Identification: Monocot stem.
Reasoning:
Reasoning:
- Conjoint vascular bundles → typical of stems and leaves (not roots, which are radial)
- Scattered (not in ring) → characteristic of monocot stems
- Sclerenchymatous bundle sheath → distinctive feature of monocot vascular bundles
- Phloem parenchyma absent → only monocots show this; dicots have phloem parenchyma
Q7. Why are xylem and phloem called complex tissues?
A simple tissue has only ONE type of cells (e.g., parenchyma — only parenchymatous cells). A complex tissue has multiple types of cells working as a unit.
Xylem is composed of FOUR cell types:
Xylem is composed of FOUR cell types:
- Tracheids (dead, water conduction)
- Vessels (dead, water conduction, more efficient)
- Xylem fibres (dead, mechanical support)
- Xylem parenchyma (living, storage)
- Sieve tube elements (living, no nucleus, food transport)
- Companion cells (living, regulate sieve tubes)
- Phloem fibres (dead, support)
- Phloem parenchyma (living, storage)
Q8. What is stomatal apparatus? Explain the structure of stomata with a labelled diagram.
Stomatal apparatus: The combination of stomatal aperture, two guard cells, and the surrounding subsidiary cells.
Structure of stomata:
[See Fig. 6.5 in Part 3 for the labelled diagram.]
Structure of stomata:
- Stomatal pore: A small opening in the leaf epidermis.
- Guard cells: Two bean-shaped (kidney-shaped) cells flanking the pore. In grasses, they are dumb-bell shaped. Have chloroplasts (unlike other epidermal cells).
- Wall thickening: Inner walls (around pore) are thick; outer walls (away from pore) are thin. This differential thickening enables opening/closing.
- Subsidiary cells: Specialised epidermal cells around guard cells; help in stomatal movement.
[See Fig. 6.5 in Part 3 for the labelled diagram.]
Q9. Name the three basic tissue systems in the flowering plants. Give the tissue names under each system.
| Tissue System | Constituent Tissues / Cells |
|---|---|
| Epidermal | Epidermis, stomata, trichomes & root hairs, cuticle |
| Ground (fundamental) | Parenchyma, collenchyma, sclerenchyma — found in cortex, pericycle, pith, medullary rays |
| Vascular (conducting) | Xylem (tracheids, vessels, xylem fibres, xylem parenchyma) + Phloem (sieve tubes, companion cells, phloem parenchyma, phloem fibres) |
Q10. How is the study of plant anatomy useful to us?
Practical and academic uses:
- Identification: Distinguishing between dicot and monocot plants by anatomy alone.
- Forestry & Timber industry: Wood quality is determined by anatomy (heartwood/sapwood, ring width, vessel size). Identifying tree species from wood samples.
- Dendrochronology: Annual rings reveal tree age, past climate, and even archaeological dates.
- Agriculture: Understanding root anatomy helps in plant breeding for drought resistance, deeper roots, faster nutrient uptake.
- Medicinal botany: Authenticating crude drugs by their anatomical features (e.g., Cinchona bark vs adulterant barks).
- Plant pathology: Diagnosing plant diseases by examining infected tissues.
- Evolutionary biology: Anatomical characters help in classifying and tracing evolutionary lineages.
- Bioinspired design: Studying plant tissues inspires lightweight, strong materials (bamboo, cellulose composites).
Q11. What is periderm? How does periderm formation take place in dicot stems?
Periderm = phellogen (cork cambium) + phellem (cork) + phelloderm (secondary cortex).
Formation in dicot stems:
Formation in dicot stems:
- As stem girth increases due to vascular cambium activity, the outer epidermis & cortex get stretched and damaged.
- A few layers of cells in the outer cortex (or sometimes from epidermis) become meristematic via dedifferentiation — forming the cork cambium (phellogen).
- Phellogen divides on both sides:
- Outwards → CORK (phellem): cells become suberised (suberin in walls), die, and form an impermeable protective layer.
- Inwards → SECONDARY CORTEX (phelloderm): living parenchymatous cells.
- Together these three layers form the periderm.
- At certain points, phellogen produces loose cells instead of cork → forms lenticels for gas exchange.
- As the stem ages, more periderm layers may form deeper — outer dead layers slough off as bark.
Q12. Describe the internal structure of a dorsiventral leaf with the help of labelled diagram.
A vertical section of a dorsiventral (dicot) leaf shows three main tissue systems:
1. Epidermal tissue system:
The dorsiventral organisation enables maximum light absorption on top + efficient gas exchange below.
1. Epidermal tissue system:
- Upper epidermis: thick cuticle, fewer stomata.
- Lower epidermis: thinner cuticle, abundant stomata.
- Palisade parenchyma — long, columnar, tightly packed cells with many chloroplasts; just below upper epidermis. Main site of photosynthesis.
- Spongy parenchyma — irregular cells with large air spaces; just above lower epidermis. Allows CO₂ diffusion to palisade cells.
- Vascular bundles run through midrib and veins; xylem on adaxial (upper) side, phloem on abaxial (lower) side.
- Bundle sheath (sometimes parenchymatous, sometimes sclerenchymatous) surrounds each bundle.
The dorsiventral organisation enables maximum light absorption on top + efficient gas exchange below.
Activity 6.5 — Tissue Sleuth
Setup: Examine these prepared slides under microscope: (1) onion epidermal peel, (2) maize stem T.S., (3) sunflower stem T.S., (4) dicot leaf V.S.
Predict: What tissue/system will dominate each slide? How will you tell dicot from monocot?
1. Onion peel: Brick-shaped epidermal cells in single layer; cellulosic walls; nuclei stain dark with iodine. → Epidermal tissue system.
2. Maize stem T.S.: Scattered vascular bundles (Y-shaped), sclerenchymatous hypodermis, no cambium → MONOCOT.
3. Sunflower stem T.S.: Vascular bundles in a ring, cambium between xylem and phloem, large central pith → DICOT.
4. Dicot leaf V.S.: Two distinct mesophyll layers — upper palisade (compact columnar) + lower spongy (loose with air spaces) → DICOT/dorsiventral.
Interactive: Tissue Quick-Quiz
A tissue with thick lignified walls, dead cells, and rigid support is:
(c) Sclerenchyma
Heartwood vs sapwood: the conducting one is:
(b) Sapwood — outer, light-coloured, living, conducts water/minerals. Heartwood is dead, only structural.
Competency-Based Questions
Q1. The Casparian strip is found in: L1 Remember
Answer: (b) Endodermis of root. Suberised band on radial/tangential walls; controls passage of water/ions into vascular tissue.
Q2. Bicollateral vascular bundles (phloem on both sides of xylem) are characteristic of: L2 Understand
Answer: (c) Cucurbita. The pumpkin/gourd family has internal phloem in addition to the usual outer phloem — a unique 'bicollateral' vascular bundle.
Q3. Differentiate xylem and phloem in terms of structure and function. L3 Apply
| Feature | Xylem | Phloem |
|---|---|---|
| Function | Water + minerals (root → top) | Food (leaves → other parts) |
| Direction | Mostly upward | Bidirectional (source → sink) |
| Conducting cells | Tracheids, vessels (DEAD) | Sieve tube elements (LIVING but enucleate) |
| Walls | Lignified | Cellulosic |
| Helper cells | — | Companion cells |
| Energy required | Passive (transpiration pull) | Active (ATP-dependent loading) |
Q4. Analyse: Why do tropical trees often lack distinct annual rings? L4 Analyse
Reason: Annual rings form because the cambium responds to seasonal variation — active in spring/wet (wide vessels) and inactive in autumn/dry (narrow vessels).
In tropics:
In tropics:
- Climate is uniform — warm and wet most of the year
- Cambium remains active relatively continuously
- No clear differentiation between "spring wood" and "autumn wood"
- Wood appears uniform without clear ring boundaries
- Difficult to age tropical trees from rings
- Some tropical trees DO show "growth zones" linked to dry seasons (in monsoonal regions)
- Carbon-14 dating or stable isotope methods are needed for tropical tree ages
Q5. Create: Design a simple paper model showing dicot stem secondary growth. L6 Create
Paper Model Design:
- Materials: Coloured paper (8 colours), scissors, glue, cardboard base, marker.
- Layers (concentric circles, smallest to largest):
- White (3 cm) = pith
- Blue (5 cm) = primary xylem
- Dark blue (7 cm) = secondary xylem (heartwood — paint it darker)
- Light blue (10 cm) = secondary xylem (sapwood)
- Orange (1 cm thick ring) = vascular cambium
- Purple (12 cm) = secondary phloem
- Yellow (1 cm thick ring) = cork cambium
- Brown (14 cm) = cork (with small slit cuts for lenticels)
- Annual rings: Draw alternating dark/light bands within secondary xylem.
- Labels: Pin labels with arrows pointing to each layer.
- Demo: Make 3 versions — Year 1, Year 5, Year 20 — to show progression.
Assertion–Reason Questions
Choose: (A) Both true, R explains A. (B) Both true, R doesn't explain A. (C) A true, R false. (D) A false, R true.
A: Sclerenchyma cells provide rigid mechanical support.
R: Sclerenchyma cells have thick lignified walls and are dead at maturity.
Answer: (A). Both true; R explains A. Lignification + cell death gives sclerenchyma the rigidity needed to support large plant bodies.
A: Apical meristem cause increase in length but not in girth.
R: Apical meristem occur at the tips of root and shoot.
Answer: (A). Both true; R correctly explains A. Position at the apex means cells divide forward (not radially), causing length increase only.
A: Stomata regulate transpiration.
R: Guard cells, surrounding stomatal pore, control its opening and closing.
Answer: (A). Both true; R explains A. Turgor changes in guard cells, driven by ion pumps, mechanically open/close the pore — directly regulating water vapour loss (transpiration).
Frequently Asked Questions - NCERT Exercises and Solutions: Anatomy of Flowering Plants
What are the most-asked NCERT exercise questions in Chapter 6 Anatomy of Flowering Plants?
NCERT Class 11 Biology Chapter 6 Anatomy of Flowering Plants exercises cover definitions, classification, structure-function relationships, labelled diagrams, and application-based questions. The MyAiSchool exercise set provides full step-by-step solutions for every NCERT question, aligned with the CBSE board exam pattern. Students should master scientific terminology, diagram labelling, and concept comparison tables to score full marks.
How should students approach labelled diagram questions in Anatomy of Flowering Plants?
For labelled diagram questions in NCERT Class 11 Biology Chapter 6 Anatomy of Flowering Plants: (1) draw a clean, large, proportional diagram with sharp pencil lines, (2) label each part with horizontal lines on the right or left side, (3) use scientific terminology (Latin/Greek names where applicable), (4) write a 1-2 line description below if asked. The MyAiSchool solutions provide editable reference diagrams aligned with NCERT textbook figures.
What types of CBSE board questions come from Chapter 6?
CBSE Class 11 Biology board questions from Chapter 6 (Anatomy of Flowering Plants) typically include: (1) 1-mark MCQs on definitions and classification, (2) 2-mark short-answers on structure-function or comparisons, (3) 3-mark labelled-diagram questions, (4) 5-mark long-answer essays combining diagram + description + significance. The MyAiSchool exercise set tags each question by mark weight and Bloom level (L1-L6).
How do I compare two biological concepts in 5-mark questions?
For 5-mark comparison questions in NCERT Class 11 Biology Chapter 6: (1) use a two-column table with feature headings down the left side, (2) compare on at least 5-6 features (structure, function, location, examples, significance), (3) include one labelled diagram if relevant, (4) end with one line on biological significance. The MyAiSchool solutions follow this CBSE-aligned tabular format consistently for full marks.
What are common mistakes in Chapter 6 exercises?
Common mistakes in NCERT Class 11 Biology Chapter 6 (Anatomy of Flowering Plants) include: (1) confusing similar scientific names or terminology, (2) skipping diagram labels or drawing too small, (3) missing examples in classification questions, (4) writing essay-style answers when a table is expected, (5) forgetting to mention biological significance. The MyAiSchool solutions highlight these traps so students avoid losing marks unnecessarily.
How does the MyAiSchool solution differ from other NCERT solution sets?
MyAiSchool Class 11 Biology Chapter 6 Anatomy of Flowering Plants solutions use NEP 2024-aligned pedagogy with Bloom Taxonomy tagged questions (L1 Remember to L6 Create), step-by-step working with biological reasoning, fully labelled SVG diagrams, comparison tables, interactive simulations, and Competency-Based Questions (CBQs) for board exam practice. Each solution is verified against NCERT textbook and CBSE marking schemes.
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