Home › Free notes › Class 11 Biology › Plant Kingdom

Plant Kingdom – Class 11 Biology notes, important questions and MCQs

NCERT Class 11 Biology, chapter 3. Notes, key terms, important questions with answers and MCQs.

Chapter overview

Kingdom Plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms, which differ in body organisation, vascular tissue and reproduction.

Groups

Algae: green (Chlorophyceae), brown (Phaeophyceae), red (Rhodophyceae); agar from Gelidium, Gracilaria.
Bryophytes ("amphibians of the plant kingdom"): gametophyte dominant, no vascular tissue (Riccia, Marchantia, Funaria).
Pteridophytes: first vascular plants, sporophyte dominant (ferns, Selaginella, Equisetum).

Seed plants and life cycles

Gymnosperms: naked seeds (Cycas, Pinus); angiosperms: seeds inside fruits, double fertilisation.
Heterospory in Selaginella and Salvinia is a step towards the seed habit.
Life cycles: haplontic (most algae), diplontic (seed plants), haplo-diplontic (bryophytes, pteridophytes).

Key terms

Bryophytes: non-vascular land plants needing water for fertilisation
Heterospory: production of two kinds of spores (micro and mega)
Alternation of generations: life cycle in which a haploid gametophyte and a diploid sporophyte generation alternate

Important questions with answers

Why are bryophytes called amphibians of the plant kingdom?2 marks

They live on land but need water for sexual reproduction, since the male gametes (antherozoids) swim to the egg.

Give three economic uses of algae.3 marks

Food (Porphyra, Laminaria, Sargassum; Chlorella and Spirulina as protein supplements), agar from Gelidium and Gracilaria for culture media and jellies, algin and carrageen from brown and red algae; they also fix carbon and release half of the world's oxygen.

Compare bryophytes, pteridophytes, gymnosperms and angiosperms on four features each.5 marks

Bryophytes: gametophyte dominant; no true roots or vascular tissue; need water for fertilisation; no seeds (Funaria, Marchantia). Pteridophytes: sporophyte dominant with true roots, stem, leaves and vascular tissue; need water for fertilisation; no seeds; some heterosporous (ferns, Selaginella). Gymnosperms: sporophyte dominant; vascular tissue (xylem without vessels in most); fertilisation by pollen tube, no water needed; naked seeds, no fruits (Pinus, Cycas). Angiosperms: sporophyte dominant; xylem with vessels and phloem with companion cells; double fertilisation; seeds enclosed in fruits (mango, wheat).

Quick revision

Bryophytes = amphibians of the plant kingdom.
Pteridophytes are the first vascular plants.
Gymnosperm seeds are naked.

Exam tips

In bryophytes the gametophyte is the main plant; in pteridophytes the sporophyte is.
For each plant group remember: dominant generation, presence of vascular tissue, need for water in fertilisation, and seed habit.

Practice MCQs

Amphibians of the plant kingdom are
1. algae
2. gymnosperms
3. pteridophytes
4. bryophytes
Show answer
Answer: (d) bryophytes. Need water for fertilisation.
Agar is obtained from
1. brown algae
2. red algae (Gelidium)
3. green algae
4. fungi
Show answer
Answer: (b) red algae (Gelidium). Red algae.
The first terrestrial plants with vascular tissue are
1. bryophytes
2. gymnosperms
3. pteridophytes
4. algae
Show answer
Answer: (c) pteridophytes. Xylem and phloem.
Gymnosperms have
1. seeds inside fruits
2. no seeds
3. naked seeds
4. spores only
Show answer
Answer: (c) naked seeds. No ovary wall.
The dominant phase in the life cycle of a fern is
1. gametophyte
2. prothallus
3. protonema
4. sporophyte
Show answer
Answer: (d) sporophyte. Fern plant itself.
Heterospory is seen in
1. Selaginella
2. Funaria
3. Riccia
4. Spirogyra
Show answer
Answer: (a) Selaginella. Micro- and megaspores.
Life cycle of seed plants is
1. haplontic
2. haplo-diplontic
3. diplontic
4. none
Show answer
Answer: (c) diplontic. Sporophyte dominant.
In gymnosperms, the endosperm is
1. triploid
2. haploid
3. diploid
4. tetraploid
Show answer
Answer: (b) haploid. Formed from the female gametophyte before fertilisation.

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.