BiologyISC Class 11 · Anatomy of Flowering Plants

Plant Tissues: Meristems, Simple Permanent Tissues, Xylem and Phloem

Updated 17 October 2026 · Fact-checked

Meristematic tissues (apical, intercalary, lateral) divide to add cells, while permanent tissues have lost the ability to divide. Simple permanent tissues are parenchyma, collenchyma and sclerenchyma; complex ones are xylem and phloem. The tissues form the epidermal, ground and vascular tissue systems.

Understand Meristematic and Permanent Tissues

Meristems. Apical meristems occur at the tips of roots and shoots and produce primary tissues (increase in length). Intercalary meristems lie between mature tissues, as in the base of grass leaves and internodes. Lateral meristems (vascular cambium and cork cambium) cause secondary growth (increase in girth). Meristematic cells are small, thin-walled, with dense cytoplasm, prominent nuclei and few or no vacuoles.

Simple permanent tissues.

Tissue	Cell wall and cells	Location	Function
Parenchyma	thin cellulose wall, living, isodiametric	cortex, pith, mesophyll	photosynthesis, storage, secretion
Collenchyma	living, thickened at corners with cellulose and pectin	hypodermis of dicot stems and petioles	mechanical support with flexibility
Sclerenchyma	dead, thick lignified wall, narrow lumen: fibres and sclereids	seed coat, fruit wall, bark, sclerenchymatous hypodermis in monocots	mechanical strength

Complex permanent tissues. *Xylem:* conducts water and minerals; elements are tracheids, vessels (dead, with perforations), xylem fibres and xylem parenchyma (the only living cells). In stems, protoxylem lies towards the centre and metaxylem outside (endarch); in roots protoxylem lies towards the periphery (exarch). *Phloem:* conducts food; elements are sieve tube elements (living, with sieve plates, no nucleus), companion cells (living, nucleated, controlling the sieve tube), phloem parenchyma (absent in most monocots) and phloem fibres (the only dead cells; absent in the primary phloem of most dicots).

Tissue systems. *Epidermal*: epidermis (with cuticle), stomata (guard cells), root hairs, trichomes. *Ground*: all tissues except epidermis and vascular bundles: cortex, pericycle, pith and medullary rays. *Vascular*: xylem, phloem and cambium. Vascular bundles are radial in roots (xylem and phloem on different radii) and conjoint in stems and leaves (xylem and phloem on the same radius); conjoint bundles are open (cambium present, dicots) or closed (cambium absent, monocots).

Meristematic and Permanent Tissues: key facts

Meristems: Apical primary growth in length
Intercalary grasses
Lateral (cambium) secondary growth in girth; Divide to add cells.
Simple tissues: Parenchyma living, thin
Collenchyma living, corners thickened
Sclerenchyma dead, lignified; Support and storage.
Complex tissues: Xylem: tracheids, vessels, fibres, parenchyma | Phloem: sieve tubes, companion cells, parenchyma, fibres; Conduction.
Vascular bundles: Radial roots
Conjoint open dicot stem
Conjoint closed monocot stem; Open has cambium.

Apical	primary growth in length
Intercalary	grasses
Lateral (cambium)	secondary growth in girth

Parenchyma	living, thin
Collenchyma	living, corners thickened
Sclerenchyma	dead, lignified

Radial	roots
Conjoint open	dicot stem
Conjoint closed	monocot stem

Meristematic and Permanent Tissues in real life

The idea, met in an everyday situation. Answer the question in your own words, then compare with the model answer. The one-line hook is what to remember.

Why a coconut shell is hard but a potato is soft

Suppose a student compares the hard shell of a coconut with the soft interior of a potato.

Name the tissue mainly responsible for each and the reason.

Try it first, then show the solutionSolution

Coconut shell: sclerenchyma (sclereids, fibres), with thick lignified walls, dead cells and a narrow lumen, giving strength.
Potato: parenchyma, with thin-walled living cells storing starch.
The thickened lignified wall explains hardness; thin cellulosic walls explain softness.

Answer: Sclerenchyma in the coconut shell; parenchyma in potato.

Memory hook: Dead and lignified means hard; living and thin means soft.

Tricks to remember Meristematic and Permanent Tissues

Short memory aids. Say each one aloud once, then use it on a question the same day.

Collenchyma: corners
Cellulose and pectin deposits at the corners of the cells.
Use it when: Identifying collenchyma in sections.
Companion cells work for sieve tubes
Sieve tubes have no nucleus; companion cells do the nuclear work.
Use it when: Phloem structure.

Meristematic and Permanent Tissues: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Tissue responsible for girth increase · 1 mark · MCQBoard level

The increase in girth of a stem is brought about by:
(a) apical meristem
(b) intercalary meristem
(c) lateral meristem
(d) permanent tissue

Try it first, then show the solutionSolution

Vascular cambium and cork cambium (lateral meristems) cause secondary growth.

Answer: (c) lateral meristem

Example 2: Simple permanent tissues · 3 marks · Short answerBoard level

Differentiate parenchyma, collenchyma and sclerenchyma with respect to the cell wall, living or dead cells, and function.

Try it first, then show the solutionSolution

Parenchyma: thin cellulose wall, living; photosynthesis, storage. (1 mark)
Collenchyma: corners thickened with cellulose and pectin, living; flexible support. (1 mark)
Sclerenchyma: thick lignified wall, dead; mechanical strength. (1 mark)

Answer: Thin living; corner-thickened living; lignified dead.

Example 3: Xylem and phloem · 4 marks · Short answerHarder board level

Name the cell types in xylem and phloem. Which cells in each are living, and what is the role of the companion cell?

Try it first, then show the solutionSolution

Xylem: tracheids, vessels, xylem fibres, xylem parenchyma; only the parenchyma is living. (1.5 marks)
Phloem: sieve tube elements, companion cells, phloem parenchyma, phloem fibres; all except the fibres are living. (1.5 marks)
The companion cell has the nucleus and controls the sieve tube element, which lacks a nucleus. (1 mark)

Answer: Xylem: only parenchyma living; phloem: fibres dead; companion cells serve sieve tubes.

Example 4: Bundles · 4 marks · Short answerHarder board level

Distinguish between open and closed vascular bundles, and between radial and conjoint bundles, with the location of each.

Try it first, then show the solutionSolution

Open: cambium present between xylem and phloem (dicot stem). (1 mark)
Closed: cambium absent (monocot stem). (1 mark)
Radial: xylem and phloem in separate groups on alternate radii (roots). (1 mark)
Conjoint: xylem and phloem together on the same radius (stems and leaves). (1 mark)

Answer: Open versus closed depends on cambium; radial in roots and conjoint in stems.

Example 5: Reading a section · 5 marks · Long answerHOTS / competency

A transverse section of a stem shows a layer below the epidermis whose cells are thickened at the corners, a ring of bundles with cambium, and a large central pith. Identify the tissue below the epidermis, the stem type, the vascular bundle type and the tissues that will increase the girth later. Why is this tissue flexible?

Try it first, then show the solutionSolution

Collenchyma hypodermis (thickened with cellulose and pectin at the corners). (1 mark)
Dicot stem (ring of bundles, large pith). (1 mark)
Conjoint, collateral and open vascular bundles. (1 mark)
The cambium (a lateral meristem) will produce secondary xylem and phloem to increase the girth. (1 mark)
Collenchyma is flexible because its walls are of cellulose and pectin, with no lignin, and the cells are alive. (1 mark)

Answer: Collenchyma; dicot stem; open conjoint bundles; cambium; flexible due to unlignified wall.

Where students lose marks in Meristematic and Permanent Tissues

The slips examiners see most often, and what to write instead.

Mistake: Calling sclerenchyma living
Writing that fibres are living cells.
Do this: Sclerenchyma cells are dead at maturity with lignified walls.
Usually costs: 1 mark.
Mistake: Confusing endarch and exarch
Reversing the position of protoxylem.
Do this: Stem: endarch (protoxylem towards the centre); root: exarch (towards the periphery).
Usually costs: 1 to 2 marks.
Mistake: Placing the cambium in monocots
Showing an open bundle in monocots.
Do this: Monocot bundles are closed (no cambium).
Usually costs: 1 mark.

Exam tips

Draw and label a cross section of a conjoint bundle.
Use a table for simple tissues.
State which cells are living in xylem and phloem.
Link tissues to functions.

Practice questions on Meristematic and Permanent Tissues

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Water is conducted mainly through:
(a) phloem
(b) xylem
(c) cambium
(d) collenchyma
Hint
Xylem carries water and minerals.
Answer
(b) xylem
Q2 · 2 marks · Short answerBoard level
Name the meristem found in the grass leaf base and state its role.
Hint
It lies between permanent tissues.
Answer
Intercalary meristem; it allows the leaf to regrow after grazing or cutting.
Q3 · 3 marks · Short answerHarder board level
Why are sieve tubes called enucleate living cells? State the role of sieve plates.
Hint
Think of conduction of food.
Answer
Sieve tube elements lose their nucleus but remain alive (supported by companion cells). The sieve plates are perforated end walls that allow the passage of food.
Q4 · 3 marks · Short answerHarder board level
Differentiate between tracheids and vessels.
Hint
Compare their ends.
Answer
Tracheids are elongated, tapering cells with pits and no perforation. Vessels are long tube-like cells joined end to end with perforations and have wider lumen, found mainly in angiosperms.
Q5 · 3 marks · Assertion-reasonHarder board level
Assertion (A): Monocot stems do not show secondary growth. Reason (R): Their vascular bundles are closed, with no cambium between xylem and phloem. Choose: (a) both true and R explains A (b) both true, R does not explain A (c) A true, R false (d) A false, R true.
Hint
Cambium makes secondary tissues.
Answer
(a) Both are true and R explains A: without a cambium no new secondary xylem and phloem can form.
Q6 · 4 marks · Case-basedHOTS / competency
Case study: Suppose a student cuts a section of the stem of a sunflower and a maize.
(i) Name the vascular bundle type in sunflower. (1 mark)
(ii) Name the vascular bundle type in maize. (1 mark)
(iii) State the arrangement of bundles in each. (1 mark)
(iv) Which one can show secondary growth? (1 mark)
Hint
Compare dicot and monocot stems.
Answer
(i) Open conjoint. (ii) Closed conjoint. (iii) Sunflower: bundles in a ring; maize: scattered. (iv) Sunflower (dicot), because it has cambium.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Support tissue with living cells?Show answer
Collenchyma.
2.Meristem for girth increase?Show answer
Lateral (cambium).
3.Conducting cells of phloem?Show answer
Sieve tube elements.
4.Cambium in monocot bundles?Show answer
Absent.

Meristematic and Permanent Tissues: frequently asked questions

What is the difference between primary and secondary growth?

Primary growth increases length from apical meristems; secondary growth increases girth from lateral meristems.

Why do sieve tubes have companion cells?

Sieve tubes lack a nucleus, so the adjacent companion cells provide the nucleus-controlled metabolic support.

What is a sclereid?

A short, branched or stone-like sclerenchyma cell, found in seed coats and the gritty flesh of guava and pear.