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Anatomy of Flowering Plants – Class 11 Biology notes, important questions and MCQs

NCERT Class 11 Biology, chapter 6. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Plant anatomy studies internal structure. Tissues are meristematic or permanent, and are arranged differently in dicot and monocot roots, stems and leaves.

Tissues

Meristems: apical, intercalary, lateral (vascular cambium, cork cambium).
Simple permanent tissues: parenchyma, collenchyma, sclerenchyma; complex: xylem (water) and phloem (food).
Tissue systems: epidermal, ground and vascular.

Dicot vs monocot

Dicot stem: vascular bundles in a ring, open (with cambium); monocot stem: scattered, closed bundles.
Dicot leaf is dorsiventral (palisade + spongy); monocot leaf is isobilateral.
Secondary growth (in dicots) adds annual rings; heartwood is dark and non-functional, sapwood conducts water.

Key terms

Meristem: tissue of actively dividing cells
Annual ring: one year's growth of secondary xylem
Casparian strips: bands of suberin on the radial and inner walls of endodermal cells in roots, blocking water from passing between cells

Important questions with answers

What is the function of guard cells?2 marks

Guard cells surround the stomatal pore and change shape with turgor to open or close the stoma, controlling gas exchange and water loss.

Distinguish between heartwood and sapwood.3 marks

Heartwood is the dark, inner part of old secondary xylem filled with tannins, resins and gums; it is dead, hard and gives strength but does not conduct water. Sapwood is the light, outer part that is functional and conducts water and minerals.

Describe secondary growth in a dicot stem, including the role of vascular cambium and cork cambium.5 marks

Vascular cambium forms a complete ring: intrafascicular cambium joins with interfascicular cambium formed from medullary ray cells. The cambium cuts off secondary xylem towards the inside and secondary phloem towards the outside, with more xylem produced; this increases girth. Seasonal activity gives spring wood (light, wide vessels) and autumn wood (dark, narrow vessels), forming annual rings. As the stem grows, cork cambium (phellogen) forms in the cortex and cuts off cork (phellem) outside and secondary cortex (phelloderm) inside; together these make the periderm. Lenticels in the cork allow gas exchange. Bark is all tissues outside the vascular cambium.

Quick revision

Open bundles have cambium.
Monocots usually lack secondary growth.
Xylem conducts water.

Exam tips

Count annual rings to estimate a tree's age (dendrochronology).
For T.S. identification remember: dicot root – radial bundles, 2–4 xylem; monocot root – more than 6 xylem with pith; dicot stem – ring of open bundles; monocot stem – scattered closed bundles with bundle sheath.

Practice MCQs

Water is conducted by
1. phloem
2. xylem
3. cortex
4. pith
Show answer
Answer: (b) xylem. Xylem.
Tissue of actively dividing cells is
1. meristematic
2. permanent
3. epidermal
4. cork
Show answer
Answer: (a) meristematic. Meristem.
Vascular bundles are scattered in
1. dicot stem
2. dicot leaf
3. dicot root
4. monocot stem
Show answer
Answer: (d) monocot stem. Monocot stem.
Age of a tree can be found by counting
1. leaves
2. roots
3. branches
4. annual rings
Show answer
Answer: (d) annual rings. Rings.
In dicot roots the vascular bundles are
1. conjoint and open
2. radial
3. collateral and closed
4. bicollateral
Show answer
Answer: (b) radial. Xylem and phloem on different radii.
Monocot leaves are
1. isobilateral
2. dorsiventral
3. cylindrical
4. needle-like only
Show answer
Answer: (a) isobilateral. Both surfaces similar.
Heartwood is
1. light and conducting
2. living tissue
3. part of phloem
4. dark and non-conducting
Show answer
Answer: (d) dark and non-conducting. Filled with tannins.
Bulliform cells in grass leaves help to
1. roll the leaf to reduce water loss
2. store food
3. absorb water
4. make chlorophyll
Show answer
Answer: (a) roll the leaf to reduce water loss. Lose turgor and curl leaf.

All chapters of Class 11 Biology

Written by Kundali IQ from standard, well-established facts to help with revision. This is not an official NCERT publication; always read your textbook too.