Botany lecture notes

Anatomy of Monocot Stem: Key Points with PPT

ts of monocot stem

Internal Structure of Monocot Stem (Transverse Section, T.S.)

The anatomy or internal structure of a monocot stem can be studied by a Transverse Section (T.S.) taken through the internode of a monocot plant such as grass, bamboo, maize, Asparagus etc. The main difference of monocot stem from dicot stem is that, here in monocots the ground tissue is NOT differentiated into Cortex and Endodermis. The anatomical features of a typical monocot stem are summarized as key points below:

@. The T.S. of a monocot stem is usually circular in outline

@. Typically a monocot stem consist of FOUR tissue systems.

(1).  Dermal tissue system

(2).  Hypodermal tissue system

(3). Ground tissue system

(4). Vascular tissue system

(1). Dermal tissue system

@. Dermal tissue system constitute the epidermis

@. Epidermis forms the outermost layer

@. Usually the epidermis is single layered and made up of parenchymatous cells

@. Epidermal cells are compactly packed without any inter-cellular spaces

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Botany lecture notes

Characteristics of Bryophytes (Life Cycle and Reproduction of Phylum Bryophyta)

Characters of Bryophytes

Mosses and Liverworts General Characteristics (Key points with PPT)

Ø  Bryophytes are the most simplest and most primitive land plants

Ø  Name bryophyte is derived from two words; ‘Bryon’ = moss; ‘phyton’ = plant

Ø  At present the phylum Bryophyta includes  ~ 960 genera and ~ 24000 species

Habit and Habitat of Bryophytes

Ø  They are cosmopolitan in distribution

Ø  Bryophytes are quite uncommon in marine environments

Ø  Bryophytes are terrestrial plants but require water at every stages in their life cycle

Ø  They grow usually in moist and shady places

Ø  They fail to complete its life cycle in the absence of water

Ø  Few bryophytes are truly aquatic and underwater forms(example Riccia fluitans)

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Botany lecture notes

Pigments in Algae (Key points) with PPT

pigments in algae

Pigmentation in algae:

Ø  Algae show great diversity in pigmentation.

Ø  Many coloured pigments such as green, red, yellow, and blue have been found in marine and freshwater algae.

Ø  Different groups of algae have different and specific pigment composition.

Ø  Pigments are usually found in specialized plastids called chromophores in all groups of algae except in the members of Cyanophyceae (blue green algae).

Ø  Distribution pattern of pigments has great taxonomic significance in algal systematics.

Ø  Classification of algae proposed by Fritsch is primarily based of the pigmentation of algae.

Ø  All major algal groups have at least one characteristic pigment in their cells.

Pigments in algae belong to THREE major categories based on their physical and chemical properties.

(1). Chlorophylls

(2). Carotenoids

(3). Phycobilins

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