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Unit - I, Chapter - 3, Science of Plants

        The term "Biology" was coined by J.B. de Lamarck (France) and Gottfrid Treveranus (Germany) 1801. This term is derived from Greek (Bios = life, logos = discourse). It is also called Natural Science. It is the story of life on earth. It deals with the study of life of plants and animals. Aristotle (Greek philosopher) (384 - 322 BC) is considered as "Father of Biology". It is divided into 2 sciences.
1. Botany, 2. Zoology

 

What is Botany?
        It is a branch of Biology. It deals with the story of origin, development and distribution of various types of plants all over the earth. It is also called Phytology. The root word for Botany is Bouskein (Greek = cattle feed). It became Botane from which Botany is derived. Theophrastus (371 - 287 BC), a student of Aristotle and classmate of Alexander, The great is known as "Father of Botany". He wrote 2 books.
1. Historia Plantarum 2. Decausic Plantarum or An inquiry into plants. Parasara is considered as "Father of Botany in India". He wrote 2 books 1. Krishi Parasharam 2. Vrikshayurveda.

History of Botany (Development)
        Let us go back 4000 yrs before the beginning of christian era! Egyptians and Assyrians are known for their first recording the information about crop plants and fruiting trees in the form of pictures. It is called Hieroglyphics.
* Chinese were the first to start the cultivation of plants i.e., agriculture (2500 BC).
* Atharvanaveda (one of the four Vedas in India) has evidence in writing (2000 BC) about 740 plants and their medicinal uses.
* Parasara (1300 BC) wrote first book on agriculture known as Krishi Parasharam. He mentioned weeds in it. Another book he wrote is Vrikshayurveda. It describes 14 types of forests, external and internal characters of plants and Medicinal plants. He also classified plants into Ganas.
*  Sushrutha and Charaka (600 BC) wrote Samhithas. Sushrutha divided plants into Vanaspati, Virudha, Osadhi and Vriksha. Charaka divided plant kingdom into 50 groups. Dhanvanthari is considered as Father of Medicine in India.

*  Socrates, Plato, Aristotle were responsible for the development of Botany into a science. They divided plants into different groups basing on their importance to human beings. Theophrastus belonging to the same school is considered as Father of Botany. He wrote (340 BC) de Historia Plantrum in which he described external and internal characters of 500 plants.
*  Dark age of Science - Stretches from the period of Theophrastus to 15th century. Nothing is known about any thing that happened during this period.
*  Period of Renaissance (16th and 17th Centuries)
It is also known as period of herbalists. A herb is a medicinal plant. Herbal is a book dealing with medicinal plants. The person who writes herbals is called Herbalist. The important herbalists are Brunfels de L' obel, Fuchs and gerard. They identified and described medicinal plants in their books.
*  Zacharias Janssen (1590) was the first to construct compound Microscope. Gaspard Bauhin was the first taxonomist to use Binomial nomenclature (1623). He identified, named, and described 6000 plants. Robert Hooke (1665) described his observations of dead cells belonging to the cork of Oak under compound microscope, in a book called Micrographia. Anton Van Leeuwenhock (1675) was the first to discover living cell (Bacteria).

Nehemiah Grew and Marcello Malpighi are the founders of Anatomy. They wrote a book Anatomic Plantarum (1675). Camerarius (1694) described sexual reproduction in plants. 17th century witnessed the development of Botany parallel to other three Sciences viz Physics, Chemistry and Astronomy.
*  Carolus Von Linnaeus (1707 - 78), a Swedish pastor, physician and botanist proposed sexual system of classification. He popularised Binomial Nomenclature in his book 'Species Plantarum'. He is considered as "Father of Taxonomy". Stephen Hales, Popularly called as Father of Plant Physiology showed that water in plants is conducted through Xylem by root pressure. Joseph priestly discovered the absorption of toxic gases and release of pure gas by green plants. 
* 19th century witnessed the birth of Genetics and Ecology. Gregor Johann Mendel (1866) proposed laws of inheritance. He worked on pea plant. He is known as Father of Genetics. Ecology was started by Ernest Haeckel (1886) de Candolle, de Jessieu, Endlicher, Bentham & Hooker proposed Natural system of classification. The central point of attraction of 19th century was Charles Darwin's theory of Evolution after which phylogenetic system of classification were proposed.

Cell theory a breaking news of 19th century was proposed by Schwann and Schleiden (1835) Waldeyer coined the term chromosomes (1888). Buchner (1898) discovered Zymase in Yeast cells.
* Golden Era of Biology (20th Century)
We are in the Golden period of Biology. It gives us a long list of discoveries and new techniques which paved the way establish many new branches of Botany.
Mutation were discovered by Hugo de vries (1901)
Sutton & Boveri (1902) proposed chromosomal theory of inheritance.
F.W. Went (1928) Discovered Auxins.
Knoll & Ruska (1932) discovered Electron Microscope which has highest resolving power.
J.B. Sumner (1926)- Crystallized urease enzyme.
Watson & Crick (1953) discovered double helix model of DNA structure.
sir Hans Krebs (1937) discovered citric acid cycle (TCA cycle)
Frankel Conrat (1956) discovered genetic nature of RNA in virus.
Avery, Mc Leod and Mc Carty discovered genetic nature of DNA

Nirenberg, Har Gobind Khorana and Holley were responsible for the understanding of Genetic code.
Har Gobind Khorana synthesised gene.
Robert Hill, Ruben, Kaman, Arnon and Emerson made possible to understand light reaction of photosynthesis.
Calvin, Benson & Basham (1953) discovered C3 Pathway.
Hatch & Slack (1967) discovered C4 Pathway.
V.S. Ram Das from India proved that C4 Pathway also occurs in dicots.
Hanning, Shimakura, Skoog, White, Nitsch, Maheshwari (Delhi) developed tissue culture.
Palynology was developed by Wodehouse, PKK Nair, Erdtman, Turill, Vishnumitre, C.G.K. Ramanujam and Sunirmal Chanda.
Bessey, Rendle & Hutchinson proposed phylogenetic system of classification.
Takhtajan (1980), Cronquist (1981), Goldberg (1986), Thorne (1992) proposed synthetic system of classification.
Ultracentrifugation - a technique to separate cell organelles.
Microchemical tests - a technique to understand the functions of cell organelles

Electrophoresis - a technique to separate biomolecules in electric field.
Chromatography - (TLC & HPLC) 2 techniques to separate chemical compounds from cell organelles.
X-ray crystallography - a technique to know the arrangement of molecules in DNA, Enzymes and proteins
DNA finger printing technique - Alec Jeffrey.

 

Scope of Botany

*  The most important needs of man are food, clothing and shelter. Plants are the only source.
*  Few uses of phytohormones in agriculture
1) Auxins in low - concentration - Initiates rooting
2) Auxins in higher concentration - Herbicide or weedicide
3) Gibberellins - seed germination
4) Cytokinins - shelf life of vegetables & fruits
5) ABA - delays sprouting of potatoes in storage
6) Ethylene - Fastens the fruit ripening.

Plants are the source of various products as follows.
Timber - Teak, Dalbergia
Fibres - Gossypium (Cotton), Corchorus (Jute)
Beverages - coffee (coffea arabica), Tea (Camellia sinensis)
Condiments - Mustard (Brassica nigra), Fenugreek (Trigonella foenum graecum)
Spices - Elaichi (Amomum aromaticum), Onion (Allium cepa)
Rubber - Indian rubber (Ficus elastica), Para rubber (Hevea sp)
Gums - Acacia arabica
Resins - Turpentine (Pinus roxburghii), Asafoeitda (Ferula sp)
Dyes - Blue dye (Indigofera tinctoria)
Essential oils - Ginger, Cedar, Cinnamon, Mint, Rose
Aromatic oils - jasmine
Antibiotics - Streptomycin (Streptomyces), Penicillin (Pencillium sp)
Bioinsecticide - BT (Bacillus thuringiensis)
Food for astronauts - Chlorella (Alga)
SCP - Chlorella, Spirulina

Proteins - Mushrooms
Iodine - Sea weeds (Laminaria)
Agar agar - Red algae (Gelidium, Gigartina) We can control the following
Green House Effect - Intensive tree plantation
Soil pollution - Bioremediation, recycling of materials by saprophytes
Soil erosion - sand binding plants.


 
Biofertilisers:
Fertilisers of biological origin are called Biofertilisers. They reduce the damage caused by the usage of chemical fertilisers. The members of cyanophyceae (Nostoc, Anabena, Aulosira), Bacteria (Rhizobium), Pteridophytes (Azolla) are used as biofertilisers.

 

Source of SCP:
Chlorella, Spirulina, Torula yeast etc are grown for proteins.

Medicinal plants
Plants are the richest source of medicines. Most of the medicines are derived from plants.
e.g.: Armica, Datura, Cinchona, Digitalis, Belladonna etc.
Petro Plants: Plants belonging to Euphorbiaceae (Jatropa), Fabaceae (Pongamia) are rich in hydrocarbons. They help us to produce diesel. It is called biodiesel. We get this fuel at cheaper price. Fossils produce Petrol, Coal, Coke and gasoline. Jatropha seed are given to the farmers at subsidised rate and thus encouraged to grow petro plants.

 

Classification of Plant Kingdom

What is classification?
        The arrangement of the plants into various groups based on their similarities and differences.

 

Why should we undertake this classification?
        Plants show wide range of diversity in their distribution, morphology, nutrition and method of reproduction. Classification helps in identification and to know other information.

Whose Classification is a right one?
        Aristotle, Theophrastus, Linnaeus and many others classified plants. But the widely accepted post Darwinian system of classification proposed by A.W. Eichler, a German Botanist. It is the first phylogenetic system of classification. It is concerned with entire plant kingdom.

Cryptos = Hidden
These are non flowering Plants. They are seedless.
They propagate through spores. So these are called spore plants.
Cryprtogamae is divided into 3 divisions.
1) Thallophyta   2) Bryophyta   3) Pteridophyta

 

Thallophyta
         It is the largest division with simplest groups of plants. The plant body is undifferentiated  and called thallus. It is further divided into two sub divisions based mainly on chlorophyll
           1) Algae       2) Fungi

Algae: These are thalloid, either unicellular or multicellular, green, autotrophic and aquatic.
e.g.: Chlamydomonas, Chlorella, Spirogyra, Scenedesmus, Volvax, Spirulina, Nostoc, Anabena, Aulosira, Acetabularia, Chlorella and Scenedesmus are widely used in physiological experiments.
        Acetabularia is used in genetical experiments. chlorella & spirulina give us single cell proteins. They are also used by space travellers. Nostoc, Anabena are used as Biofertilisers. They fix nitrogen & improve the soil fertility.
"The study of algae is called 'Phycology'.
or Algology. M.O.P. Iyengar is considered as 'Father of Phycology in India'

Fungi: The plant body is called mycelium. It is highly branched. The branches are called hyphae. These are non-chlorophyllous, heterotrophic, saprophytic or parasitic, pathogenic or non - pathogenic which live on/in wide variety of habitats.
"The study of fungi is called Mycology" or Mycetology.

        Pier Antonio Michaeli is considered as Father of Mycology. de Bary is considered as Father of Modern mycology.
e.g.: Yeast, Neurospora, Aspergillus, Pencillium, Mushrooms, Rhizopus.
        The fungus that derives nutrition from dead and decaying is called saprophyte.
The source that supplies food to the saprophyte is called substratum. The fungus that derives nutrition from living organisms is called parasite. Its living source is called host.
     First antibiotic Penicillin is derived from Pencillium Neurospora and Aspergillus are used in genetical experiments. Yeast is used in Bakeries, Mushrooms are the richest source of proteins.


 
Some fungi associate with roots of higher plants it is called Mycorrhiza. It is another example for symbiosis.

Bacteria are unicellular, Prokaryotic, haploid, microscopic, green or non green, autotrophic or heterotrophic, pathogenic or non pathogenic omnipresent micro organisms.
           The study of bacteria is called Bacteriology.
           Some important Bacteria are
           Rhizobium, Agrobacterium, E.coli, Rhizobium fixes nitrogen. Agrobacterium and E. coli are used in genetic engineering experiments. Several antibiotics are derived from bacteria (e.g.: Streptomycin)
         Viruses are a cellular, nucleo proteinaceous, neither living nor non-living, microscopic obligatory intracellular, pathogenic & parasitic.
         Study of viruses is called virology. They cause important diseases like polio, AIDS, small pox etc...
Bryophyta: The plant body in thallus. It is green, autotrophic and non-vascular highly developed cryptogams. These are the simplest first land plants. But they require water for fertilization. So they are called as Amphibians of plant kingdom.
       These are the first embryo bearing plants. The study of bryophytes is called bryology. Riccia and Marchantia are liver worts. Funaria is a Moss Plant. Sivaram Kashyap is considered as Father of Bryology in India.

Pteridophyta: These are the first vascular plants. Their plant body is divided into Root, Stem and leaves. These are the highly advanced cryptogams. These are also called Reptiles of the plant kingdom or Botanical snakes.
e.g.: Lycopodium, Selaginella, Equisetrum, Marsilla, Pteris etc.
        Highly developed among the pteridophytes are Ferns.
e.g.:  Pteris, Azolla. Azolla is a rootless, aquatic biofertiliser.
Phanerogams: These are flowering or seed plants. They include only one division i.e., Spermatophyta. It is divided into 2 sub divisions  1) Gymnospermae    2) Angiospermae.
Gymnospermae: (Gymnos = Naked, Sperma = seeds). The flowering plants which bear naked seeds (i.e. seeds not covered by fruitwall) are called Gymnosperms. They are mostly trees.
e.g.: Cycas, Pinus, Gnetum, Sequoia.
Angiospermae (Angios = closed, Sperma = seeds.)
        The flowering plants which produce seeds covered by fruit wall are called Angiosperms. These are divided into 2 classes.
1) Dicotyledonae: e.g.:  Ground nut, Pea, Ficus, Mango.
2) Monocotyledonae: e.g.:  Rice, Wheat, Coconut, Maize.

Branches of Botany: Some branches of Botany are mentioned at their appropriate places during classification. The remaining are as follows:
Morphology: The study of different plant organs is called as Morphology. Botanist concerned with it is called Morphologist. It is divided into two types.
1) External Morphology: It deals with the study of external characters of various organs of the plant. It is essential for classification. So a taxonomist must be a morphologist first.
2) Internal Morphology: It deals with internal structure of different organs of the plant.
It is divided into two branches
1) Histology: The study of various kinds of tissues is called Histology or Microanatomy. Tissue is a group of cells which perform a common function.
2) Anatomy: It deals with internal structure or distribution of various kinds of tissues in different organs of the plant. It is also called Organography.
Cytology: The study of cell, its various organelles and cell division is called cytology or Cell Biology. The scientist concerned with it is called cytologist. The unit of life is called cell.
Palynology: Microspores are also called pollen grains. It is the first cell of male gametophyte. The study of the structure and development of pollen grains is called Palynology.

The scientist concerned with Palynology is called Palynologist. C.G.K. Ramanujan, P.K.K. Nair, Vishnu Mitre and Sunirmal Chanda are great Indian Palynologists.
Taxonomy: It deals with identification, nomenclature and classification of plants. It is also called systematic Botany or New systematics. It is not an independent branch. It depends upon other branches of Botany.
Plant Physiology: The study of various metabolic functions of the plants is called Plant Physiology.
        The metabolic functions include osmosis, transpiration, photosynthesis, Respiration etc.
Genetics: The transfer of characters from parents to the offspring is called heredity.
The differences in the characters of parents and offspring are called variations.
The branch of Biology which deals with heredity and variations is called Genetics.
Ecology: The study of Plants and animals in relation to their environment is called Ecology or Environmental Biology.
The study of the plants in relation to their environment is called plant ecology.


Embryology: The study of male gametophyte, female gametophyte, fertilisation and the development of embryo, endosperm and seed is called Embryology or Developmental biology.


              
Agriculture: It is an applied branch of Botany which deals with the study if cultivation, farming and raising crops.
Forestry: It is an applied branch of Botany that deals with the study of development and management of forests.
Horticulture: It is an applied branch of Botany that deals with the study of the development of flower and fruit yielding plants. It also deals with development of orchards and gardens.
Floriculture: It deals with the cultivation of plants for flowers.
Pomology: The study of fruits is called pomology
Olericulture: The study of the cultivation of vegetable yielding plants is called Olericulture.
Plant Breeding: It is also an applied branch of Botany. It deals with various techniques (like hybridisation, mutations, genetic engineering) to obtain a better variety of crop plants than the existing ones.

Palaeobotany: The extinct plants are called fossils. The plants which lived once and whose species are no more to be seen are called plant fossils. These are found in the form of impressions or traces.
The study of plant fossils is called Palaeobotany. It helps in understanding the process of evolution and provides evidence.


            
        Sahni was the first to study fossil flora of Indian gondwana Land. He reported several new fossil genera from Rajmahal hills of Bihar.
Phytogeography: The branch of Botany that deals with the distribution of plants in different parts of the globe (in the past and present) is called phytogeography. It is a branch of Biogeography.
Biotechnology: It is the latest and most popular branch of Biology. It is the science of utilising the properties & uses of micro organisms or exploit cells and cell constituents at industrial level for generating useful products essential to life and human welfare.

Bioinformatics: It is also a new branch of Biology. It deals with the application of computational techniques to the management of biological information. It helps in Gene mapping, DNA sequencing and protein sequencing. Bioinformatics is also called silicon based biology.
Biometry: It deals with the application of statistics or statistical data in studying biological problems. 
Biostatistics: It is now used in recording results, analysis, comparison and interpretation.
Plant pathology: The study of plant disease, causative agents and their controlling measures is called as plant pathology. 

Posted Date : 29-07-2021

గమనిక : ప్రతిభ.ఈనాడు.నెట్‌లో కనిపించే వ్యాపార ప్రకటనలు వివిధ దేశాల్లోని వ్యాపారులు, సంస్థల నుంచి వస్తాయి. మరి కొన్ని ప్రకటనలు పాఠకుల అభిరుచి మేరకు కృత్రిమ మేధస్సు సాంకేతికత సాయంతో ప్రదర్శితమవుతుంటాయి. ఆ ప్రకటనల్లోని ఉత్పత్తులను లేదా సేవలను పాఠకులు స్వయంగా విచారించుకొని, జాగ్రత్తగా పరిశీలించి కొనుక్కోవాలి లేదా వినియోగించుకోవాలి. వాటి నాణ్యత లేదా లోపాలతో ఈనాడు యాజమాన్యానికి ఎలాంటి సంబంధం లేదు. ఈ విషయంలో ఉత్తర ప్రత్యుత్తరాలకు, ఈ-మెయిల్స్ కి, ఇంకా ఇతర రూపాల్లో సమాచార మార్పిడికి తావు లేదు. ఫిర్యాదులు స్వీకరించడం కుదరదు. పాఠకులు గమనించి, సహకరించాలని మనవి.

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