CBSE Class 11 Biology: What is the Plant Kingdom?

Overview

Do you know what the five-kingdom classification for living organisms is? Well, it is a classification for living organisms that were given by R.H. Whittaker. He characterized all the living organisms based on various characteristics such as mode of nutrition, cellular structure, reproduction, body organization, and many other aspects. Among all the five kingdoms, here are the classification and characteristics of the Kingdom Plantae.

What do you understand about the Plant Kingdom?

The five Kingdom classifications included Monera, Protista, Fungi, Plantae, and Animalia. Do you have a conceptual understanding of the Plant Kingdom? If not, keep reading to find out.

The Plant Kingdom includes all the plants. These organisms are eukaryotic, multicellular, and autotrophic in nature. All plant cells are characterized by having a rigid cell wall. Apart from this, plants have a chloroplast that contains the pigment called chlorophyll. This is a green pigment that is required for the process of photosynthesis.

Do you know what the different characteristics of plants that you see around you are? Keep reading to find out about it.

What are the characteristics of Plant Kingdom?

Even though plants surround us from everywhere, there are particular characteristics associated with the Plant Kingdom. The Plant Kingdom is characterized by the following features-

• They are non-motile.
• They are called autotrophs because they make their own food.
• They reproduce asexually through vegetative propagation or through sexual methods.
• Organisms in the Plant Kingdom are multicellular, eukaryotic organisms.
• All the plant cells contain an outer cell wall and a large central vacuole.
• Plants contain a green photosynthetic pigment called chlorophyll. 
• The chlorophyll is present in the chloroplasts.
• All the plants in the Plant Kingdom have different organelles for reproduction, support, anchorage, and photosynthesis.

Do you know what photosynthesis is? It is a process by which plants containing the green pigment chlorophyll make their own food with the aid of sunlight, water, and carbon dioxide.

What are Cryptogams and Phanerogams?

The Plant Kingdom is divided into two groups –

• Cryptogams- these are the non-flowering and non-seed bearing plants. For example – Thallophyta, Bryophyta, and Pteridophyta.
• Phanerogams- these plants have flowers as well as seeds. For example – Gymnosperms and Angiosperms.

Classification of Plant Kingdom Plantae

All the plants in the Plant Kingdom are further divided and classified into subgroups. This classification is done on the basis of the following criteria:

1. Plant body: It means that the plants are classified on the basis of their presence or absence of a well-defined plant body or parts of a plant. E.g. leaves, stem, and root.
2. Vascular system: Whether a certain type of plant has a vascular system which is responsible for the transportation of water and other substances. For example- Xylem and phloem.
3. Seed formation: Whether the plants can have seeds and flowers and whether the seeds are naked or enclosed.

This is an important chapter that has a lot of weightage in the CBSE Class 12 Term 2 exams.

Pop quiz: Do you know what makes up the vascular system? And, what do you understand about vascular tissues in plants and their function?

Also See: Explanation of Plant Cell | Difference Between Plant Cell And Animal Cell

1. Thallophyta

The Plant Kingdom has a division called Thallophyta, which includes primitive forms of plant life. These forms show a simple plant body. This particular division includes unicellular to large algae, fungi, and lichens. 

1. Algae

• Algae contain chlorophyll and hence are autotrophic in nature.
• Algae are mostly present in aquatic life forms.
• They also occur in a variety of habitats: wood, moist stones, and soils.
• Sometimes, Algae also occurs in association with fungi and are called Lichens.
• Their asexual reproduction is by fragmentation.
• Their sexual reproduction takes place by the formation of gametes.
• Algae is further divided into three classes- Chlorophyceae, Phaeophyceae, and Rhodophyceae.

2. Fungi

• Fungi are eukaryotic organisms that also include microorganisms such as mould, yeasts, and mushrooms.
• They do not have chlorophyll.

3. Lichens

• Lichens Formed as a symbiotic relationship between algae and fungi.
• These organisms are of considerable economic importance.

Pop quizHow are Lichens beneficial as a medicine?

2. Bryophyta

• Bryophytes include mosses and liverworts. They grow in moist areas in the hills.
• They are typically called amphibians of the Plant Kingdom.
• Bryophytes depend on water for sexual reproduction.
• Their bodies are now advanced and well-differentiated from Algae.
• They are attached to the substratum by rhizoids (unicellular or multicellular).
• The main body of the plant is a haploid.
• They are called gametophytes as they produce gametes.

Reproduction in Bryophytes

• The sex organs are multicellular.
• The male sex organ is called antheridium.
• The archegonium is known as the female sex organ.
• Both the male sex organ as well as the female sex organ are fused in the water for fusion.
• The antherozoid fuses with the egg to form the zygote.

1. Liverworts

• Liverworts usually grow in moist, dirty habitats such as banks of rivers, damp soil, marshy ground, the bark of trees, and deep in the woods.
• The plant body of a liverwort is called a thalloid, e.g., Marchantia.

2. Mosses

• The premature stage of the life cycle of mosses are called the gametophyte. It consists of two main stages.
• The first stage of its life cycle is known as the protonema stage. It develops directly from a spore.
• This stage is seen as a creeping, green, branched, and usually filamentous type of stage.
• The second stage comes from the leafy stage. It happens after the secondary protonema, in the shape of a lateral bud. They have slender, upright axes that bear spirally arranged leaves.

Have you seen mosses under the microscope? Try to differentiate the parts of its plant body.

3. Pteridophyta

• They are exclusively used for medicinal purposes.
• Pteridophytes are widely grown as ornamentals.
• They have a well-differentiated plant body, including roots, stems, leaves, and the vascular system.
• The main plant body is a sporophyte.
• They are the first-ever terrestrial plants to possess vascular tissues.
• The spores are produced by meiosis in spore mother cells.
• Pteridophytes are further divided into- Psilopsida, Lycopsida, Pteropsida, and Sphenopsida.

Pop quizDo you know which is the smallest and the biggest plant in the Plant Kingdom? Try to find out and learn about their characteristics.

4. Gymnosperms

• Gymnosperms are the plants that have ovules that are not surrounded by the ovary wall. The ovules remain exposed, both before and after fertilisation.
• Gymnosperms are woody and perennial. 
• They form bushes or trees.
• Some are very large, while some are very small in size.
• The stem might be unbranched or branched.
• They have a taproot.
• They have either simple or compound leaves.
• The seeds are not entirely enclosed within an ovary or fruit.
• Gymnosperms produce haploid microspores as well as megaspores.
• Their seeds are directly open to the air, where they are fertilised by pollination.
• For example – Pinus, Cycas, Gingko, and many others.

Pop quizWhich plant in the gymnosperm category is the oldest plant on earth?

5. Angiosperms

• These plants bear seeds.
• Angiosperms have well-differentiated plant bodies.
• In these plants, the seeds are entirely enclosed by fruits.
• The male sex part is called the stamen.
• The female sex part in the flower is called the pistil or the carpel.
• Some Angiosperms are microscopic, while some are tall trees.
• The pistil contains an ovary that is enclosed by one or many ovules.
• For example – Eucalyptus, Orchids, Rafflesia, and many more.

Curiously enoughRafflesia is the largest flower. It belongs to the angiosperm category of the Kingdom Plantae.The smallest angiosperm is Wolfie.The largest tree is the Eucalyptus tree.

Pop quizIdentify and write down any three gymnosperms and three angiosperms around you.

This is an important chapter while preparing for NEET Biology.

Divisions of angiosperms

The plants that are included in the category of angiosperms are further divided into two broad divisions.

•  Monocotyledons

These are the types of flowering plants whose embryo has only one cotyledon. And it is why they are called monocots.

• Dicotyledons

These are the division of angiosperms where the flowering plant has cotyledon in pairs.

Some solved questions for you

Q: Specialised tissue for conduction of water and other food materials are present in which of the following?

1. Pteridophyta
2. Gymnosperms
3. None of these
4. Both of these

Ans: The correct option is “D”. Both Gymnosperms and Pteridophytes are the types of plants that have specialized vascular tissue.

Q: Thallophyta, Bryophyta, and Pteridophyta are together called as?

Ans: They are called Cryptogams. It is because these are non-seed-bearing plants. Apart from this, these plants also do not show flowering.

Q. Amphibians’ of plant kingdom are__________________

A. Thallophyta

B. Bryophyta

C. Lichens

D. Rhodophyta

Answers: Bryophytes

Still, getting doubts about the classification and characteristics of the Plant Kingdom? Please refer to the FAQs below!

Frequently asked questions about the Plant Kingdom