Maharashtra Board Class 11 Biology Chapter 3 Kingdom Plantae PDF Download

Kingdom Plantae

In earlier chapter, we have studied different aspects of classification. Kingdom Plantae is further classified on the basis of characteristics like absence or presence of seeds, vascular tissues, differentiation of plant body, etc.

Phanerogams are commonly called seed producing plants. They produce special reproductive structures that are visible (Phaneros – visible)

Cryptogams are spore producing plants and do not produce seeds and flowers. They reproduce sexually by gametes but sex organs are concealed (kryptos : hidden, gamos : marriage).

Classification of Kingdom Plantae is represented as follows :

Teacher's Note

In India, we see many plants without flowers like ferns in the rainy season. These are the cryptogams. The plants with flowers like rose and mango are phanerogams.

Exam Trick

Remember: Cryptogams = hidden sex organs. Like secret things are hidden, cryptogams also hide their sex organs.

Points to Remember

Phanerogams produce seeds and have visible reproductive structures.

Cryptogams produce spores, not seeds.

Kingdom Plantae has two main groups - Cryptogams and Phanerogams.

Vascular plants have tubes to carry water and food.

Salient Features Of Major Plant Groups Under Cryptogams

Division: Thallophyta

Members are mostly aquatic, few grow on other plants as epiphytes. Some grow symbiotically and epizoic. This means growing or living non-parasitically on the exterior of living organisms. Aquatic algae grow in marine or fresh water. Most of them are free living while some are symbiotic.

Plant body is thalloid. This means undifferentiated into root, stem and leaves. They may be small, unicellular, microscopic like Chlorella (non-motile) or Chlamydomonas (motile). They can be multicellular, unbranched, filamentous like Spirogyra or branched, filamentous like Chara. Sargassum, a huge macroscopic sea weed which measures more than 60 meters in length is also an alga.

The algal cell wall contains either polysaccharides like cellulose or glucose or a variety of proteins or both. Reserve food is in the form of starch and its other forms. Reproduction takes place by vegetative asexual and sexual way. The life cycle shows phenomenon of alternation of generation, dominant haploid and reduced diploid phases. Algae are classified as per its pigments like chlorophyll, xanthophylls and phycobilin.

Chlorophyceae (Green Algae)

These are mostly fresh water (few brackish water and marine).

Plant body is unicellular, colonial, filamentous. Cell wall contains cellulose.

Chloroplasts are of various shapes like discoid, plate-like, reticulate, cup-shaped, ribbon-shaped or spiral with chlorophyll a and b. The stored food is in the form of starch.

Pyrenoids are located on Chloroplast. Members are rich in protein, so used as food. They are used even by space travellers. Examples are Chlorella, Chlamydomonas, Spirogyra, Chara, Volvox, Ulothrix etc.

Teacher's Note

In India, many people use green algae like Chlorella as a health supplement. It is very nutritious and good for our body.

Exam Trick

Remember: Chlorophyceae = green colour = chlorophyll a and b. Green algae are green because they have chlorophyll.

Points to Remember

Green algae are mostly found in fresh water.

They have chlorophyll a and b.

They store food as starch.

Their cell wall is made of cellulose.

Pyrenoids help in storing starch.

Phaeophyceae (Brown Algae)

Plant body: Mostly marine, rarely fresh water. Simple branched or filamentous (example: Ectocarpus) or profusely branched (Petalonia).

Cell wall has cellulose, fucans and algin. Photosynthetic pigments like chlorophyll-a, -c and fucoxanthin are present. Mannitol, laminarin and starch are stored food materials. Body is usually differentiated into holdfast, stalk called stipe and leaf-like photosynthetic organ called frond. Many species of marine algae are used as food. Examples are Porphyra, Laminaria, Sargassum. Some species are used for production of hydrocolloids. Examples are Ectocarpus, Fucus, etc.

Teacher's Note

In Japan and Korea, people eat brown algae like seaweed. It is very healthy and has many nutrients. Some brown algae are used to make ice cream thicker.

Exam Trick

Remember: Brown algae = marine = big size. Most brown algae live in ocean water and grow very large.

Points to Remember

Brown algae are mostly found in marine water.

They have chlorophyll a and c and fucoxanthin.

Their cell wall has algin which is used in industry.

They have holdfast, stipe and frond.

Many brown algae are used as food.

Rhodophyceae (Red Algae)

Plant body: These are found in marine as well as fresh water on the surface, deep sea and brackish water. Plant body is thalloid. Cells contain chlorophyll a, d and phycoerythrin. Cell wall is made up of cellulose and pectin glued with other carbohydrates. Stored food is in the form of Floridean starch. Commercially important agar-agar which is used as solidifying agent in tissue culture medium is obtained from red algae. Examples are Chondrus, Batrachospermum, Porphyra, Gelidium, Gracillaria, Polysiphonia, etc.

Teacher's Note

Red algae are used to make agar-agar. In India, agar is used in science labs and in kitchens for making jellies.

Exam Trick

Remember: Red algae = agar-agar = jelly. Red algae make the jelly we use in labs and in sweets.

Points to Remember

Red algae are found in marine and fresh water.

They contain chlorophyll a and d and phycoerythrin.

They store food as Floridean starch.

Agar-agar is obtained from red algae.

They are found in deep sea also.

Bryophyta (Bryon : Moss ; Phyton : Plant)

Bryophytes are mostly terrestrial plants. They are found in moist shady places. But they need water for fertilization and completion of their life cycle. Hence they are called amphibious plants. They include approximately 960 genera and about 25,000 species.

Life cycle of Bryophytes shows sporophytic and gametophytic stages. Vegetative plant body is thalloid or leafy which represents gametophytic generation. Spore producing capsule represents sporophytic generation.

Bryophytes have root-like structures called rhizoids. Rhizoids are unicellular in liverworts while multicellular in mosses. Rhizoids absorb water and minerals and also help in fixation of thallus on the substratum.

Bryophytes are divided into two groups: liverworts and mosses.

Liverworts (Hepaticeae)

These are lower members of Bryophyta. These are primitive group of Bryophytes. Gametophyte possesses flat plant body called thallus. The thallus is green, dorsiventral, prostrate with unicellular rhizoids. Examples are Riccia, Marchantia.

Teacher's Note

In the rainy season, you can see small moss-like plants on wet walls. These might be liverworts. They are the simplest land plants.

Exam Trick

Remember: Liverworts = liver-shaped thallus = flat body. Their body looks like a liver shape and is very flat.

Points to Remember

Liverworts are the simplest bryophytes.

They have a flat thallus body.

They have unicellular rhizoids.

They grow in moist places.

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