Kingdom Plantae: Various types of plants surround us. Each plant can be distinguished by its leaves, stems, flowers, and fruits. They grow in different habitats. Do you know why they do not look similar? There are many plants on this earth, and they have different morphological and anatomical features and different reproductive processes. The classification of all plants in Kingdom Plantae is done according to their characteristics. Kingdom Plantae is a vast group in which plants are classified into subgroups. It is essential to know about plants and their functions and characteristics. 

Read on to know more about Kingdom Plantae and different reproductive processes. The classification of all plants in Kingdom Plantae is done according to their characteristics. Kingdom Plantae is a vast group in which plants are classified into subgroups. It is essential to know about plants and their functions and characteristics. Read on to know more about Kingdom Plantae.

Kingdom Plantae: Definition

All plants on this earth belong to Kingdom Plantae. Kingdom Plantae is a group that includes autotrophic, multicellular, photosynthetic eukaryotes. These are mainly non-motile, embryo forming, and function primarily as the producers in the ecosystem because they can fix solar energy in chemical energy through photosynthesis. They have a rigid cell wall mainly made up of cellulose.

Kingdom Plantae: Characteristics

The few characteristics of Kingdom Plantae are given below:

• Plants are essentially autotrophic, chlorophyll-containing, non-motile organisms.
• They are multicellular eukaryotic organisms.
• They have a cell wall in their cells, made up of cellulose, hemicellulose, and pectin.
• They occupy the base of the ecological pyramid and are called producers.
• They do not move from one place to another, i.e., fixed in one place.
• They reproduce by vegetative, sexual, and asexual methods.
• They show alternation of generation.

Classification of Plant Kingdom

Taxonomy is the system of classification. To study the different organisms living on earth, biologists have sorted and classified them based on their similarities and differences. All plants are, however, included in one Kingdom Plantae and are further divided into sub-groups. The classification of plants is based on a few criteria. These are:
(a) Plant Body- Presence or absence of a well-differentiated root, stem, and leaves.
(b) Vascular System- Presence or absence of vascular tissues like xylem and phloem to transport water and other substances.
(c) Seed Development- Presence or absence of flowers and seeds. The seeds are naked or enclosed in a fruit.

What is Plant Kingdom Classification?

The first sub-kingdoms consist of plants that are non-vascular and seedless plants known as Cryptogamae. The second sub-kingdoms are consisting of vascular and seed-bearing plants known as Phanerogamae.

(1) Subkingdom Cryptogamae

• Cryptogams consist of seedless plants and plant-like organisms.
• Cryptogams do not form flowers and fruits as well.
• Most cryptogams do not have a vascular system.
• The plant body is not differentiated into roots, stems, and leaves.
• They are less evolved plants.
• They can reproduce by spores.
• Cryptogams can be divided into Thallophyta, Bryophyta, and Pteridophyta.

Fig: Cryptogams

(a) Division Thallophyta
These plants exhibit the following characteristics:

• Thallophytes are eukaryotic, autotrophic (holophytic), chlorophyll-containing, non-vascular plants.
• The plant body is thalloid. The plant body is without stem, leaf, or root differentiation. They are colonial, can exist with filament, and may or may not have branches.
• These are the most primitive and simple forms.
• These are mainly present in both marine and freshwater habitats.
• The leading reserve food is starch.
• These are characterised by the absence of the embryonic stage and the presence of non-jacketed gametangia.
• Some common thallophyta examples are Volvox, Fucus, Polysiphonia, Ulothrix, Chara, and Spirogyra.

(b) Division Bryophyta
They are known as the amphibians of the plant kingdom. They exhibit the following characteristics:

• Bryophytes are autotrophic, non-seeded, cryptogamic plants.
• The plant body is gametophytic and may be divided into stem, leaves, and rhizoids.
• These are the connecting link between algae and pteridophytes.
• These are mainly present in moist, damp, shaded areas in hills or water bodies.
• They do not possess proper vascular tissues, but some of them have hydroids (like xylem) and peptoids (like phloem) which help in the conduction of water and food, respectively.
• The sex organs in bryophytes are multicellular. The male sex organ is called antheridium, and the female sex organ is called archegonium.

(c) Division Pteridophyta
They are known as the first true land plants. They exhibit the following characteristics:

• Pteridophytes are seedless, vascular cryptogams.
• The plant body is sporophyte and divided into stem, leaves, and roots.
• These are the first plants to evolve vascular tissues.
• These are mostly found in cool, damp, and shady places.
• They possess compound leaves with leaflets known as the pinna.
• They show heterospory, which gives rise to seed habit in higher plants.

(2) Subkingdom Phanerogamae

• Phanerogams consist of seeded plants.
• Phanerogams form flowers and fruits as well.
• Phanerogams have well-developed vascular systems.
• The plant body is differentiated into root, stem, and leaves.
• They are highly evolved plants.
• They have well-developed reproductive organs.
• Phanerogams can be divided into Gymnosperms and Angiosperms.

Fig: Phanerogams

(a) Gymnosperms
They are also known as Phanerogamic Spermatophyta (seed-bearing). They exhibit the following characteristics:

• Gymnosperms are naked seeded plants, which evolved earlier than the flowering plants.
• The plant body is sporophyte and differentiated into root, stem, and leaves.
• They include medium-sized trees or tall trees and shrubs.
• The pollens are always carried by wind (Anemophily).
• Mostly, all gymnosperms are heterosporous, producing microspores (male spores) and megaspores (female spores).
• The gymnosperms show an alternation of generation in their life cycle with a diplontic life cycle.

(b) Angiosperms
They are also known as flowering plants. They exhibit the following characteristics:

• Angiosperms are seed-bearing plants.
• The plant body is divided into the root system, shoot system, and leaves.
• They can be found in different types of habitats.
• The seeds are enclosed in an ovary which develops into a fruit.
• They exhibit double fertilisation.
• They are further divided into monocots and dicots depending on the number of cotyledons present in seeds.

What are the Examples of Kingdom Plantae?

Cryptogame

Examples of Thallophytes: Chlamydomonas, Chlorella, Spirogyra, Zygnema, Ulothrix, Cladophora, etc.

Fig: Chlamydomonas

Examples of Bryophytes: Riccia, Marchantia, Porella, Funaria, Sphagnum, Polytrichum, etc.

Fig: Marchantia

Examples of Pteridophytes: Psilotum, Rhynia (fossil), Lycopodium, Selaginella, Equisetum, Pteris, Dryopteris, Nephrolepis, Adiantum, etc.

Fig: Equisetum

Phanerogamae

Examples of Gymnosperms: Cycas, Pinus, Ginkgo, Gnetum, Ephedra, Juniperus, etc.

Fig: Pinus

Examples of Angiosperms: Apple, Mango, Cabbage, Carrot, Rice, Wheat, Atropa, Cinchona, Rauwolfia, etc.

Fig: Rice

Kingdom Plantae: Importance

The importance of Kingdom Plantae is mentioned below:

• Plants provide food to nearly all organisms, including humans. All cereals, roots, pulses, vegetable crops, etc., we get from plants. We are directly or indirectly dependent on plants.
• Plants play a significant role in maintaining the atmosphere.
• Plants produce oxygen during photosynthesis, which is very important for cellular respiration for all aerobic organisms.
• Plants help in removing the greenhouse effect and global warming.
• Plants play a significant role in the recycling of matter in biogeochemical cycles.
• Plants provide many products for human use, such as firewood, timber, fibres, medicines, dyes, pesticides, oils, and rubber.
• Plants provide habitats for many organisms. A single tree may provide food and shelter to many insects, worms, small mammals, birds, and reptiles.
• Plant products like Aloe vera, lavender oil, rosemary, etc., help to prepare cosmetics.
• Plants form the base of all terrestrial food chains.
• Some plants provide liquid hydrocarbons as a substitute for liquid fuels. The hydrocarbons that are present in these plants can be transformed into petroleum hydrocarbons. These plants are known as petrolplants. These include the members of the family Euphorbiaceae, Apocynaceae, Urticaceae etc. In India, Jatropha oil can be used as an efficient and environmentally clean biofuel substitute for diesel.
• Lichen is a symbiotic association of an alga and a fungus that acts as a bioindicator for air pollution.

Summary

The Plantae kingdom is the group of all plants that are found on the earth. Further, the kingdom Plantae has been classified into several subgroups based on the plant body, vascular system, and seed development. These groups are Thallophyta, Bryophyta, Pteridophyta, Angiosperms, and Gymnosperms. The plants belonging to these groups have some differences as well as have few similarities also.

The main aim of classification was to identify, name, and understand the relationship among these plants. Though the Plantae kingdom is not the largest, it is an essential one. Plants produce almost all the oxygen on earth. Plants also have ecological and economic importance. It brings stability to the ecosystem and plays a vital role in providing food for animals and humankind. Additionally, they provide clothing, timber, medicines, etc.

Frequently Asked Questions Related to Kingdom Plantae

Below are the frequently asked questions with solutions related to Kingdom

Q.1: How is the Plantae Kingdom classified?
Ans: The kingdom Plantae is divided into two subkingdoms: Cryptogamae and Phanerogamae.

Q.2: What are the 5 major characteristics of the Kingdom Plantae?
Ans: The five major characteristics of the Plantae kingdom are as follows:

• Plants are essentially autotrophic, chlorophyll-containing, non-motile organisms.
• They are multicellular eukaryotic organisms.
• They have a cell wall in their cells, made up of cellulose, hemicellulose, and pectin.
• They occupy the base of the ecological pyramid and are called producers.
• They do not move from one place to another, i.e., fixed in one place.

Q.3: What do you mean by Kingdom Plantae?
Ans: Kingdom Plantae is a group that includes multicellular, photosynthetic eukaryotes. These are mainly non-motile, embryo forming, and function primarily as the producers in the ecosystem.

Q.4: What are 3 examples of Plantae?
Ans: The 3 examples of Plantae are Chlorella, Pinus, and Wheat.

Q.5: Name the pigment that is responsible for the process of photosynthesis in plants?
Ans: The pigment chlorophyll is responsible for the process of photosynthesis in plants.

Q.6: Which plants are known as ‘amphibians of the plant kingdom’?
Ans: Bryophytes are known as ‘amphibians of the plant kingdom’.

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