Systematic Botany of Angiosperms Complete Notes for B.Sc., M.Sc. Botany.

Systematic Botany of Angiosperms

Taxonomy: Digestive System Queen & Servant of Botany

Read previous article: An Introduction to Plant Taxonomy

Classification of Plant Kingdom

1. Prokaryotes

1.  Bacteria
2. Cyanobacteria

2. Algae / Eukaryotic Algae

Classification Fritch / pigment

1. Chlorophyceae   (green  algae)
2. Xanthophyceae     (Yellow-green  algae)
3. Chloromonadineae
4. Euglenophyceae
5. Chrysophyceae
6. Cryptophyceae
7. Pyrrophyceae (Dinoflagellates)
8. Bacillariophyceae (Diatoms)
9. Phaeophyceae (Brown  algae)
10. Rhodophyceae (Red  algae)
11. Myxophyceae (blue-green algae)

3. Fungi

Based on the sexual spore formation:

1. Zygomycetes
2. Ascomycetes
3. Basidiomycetes
4. Deuteromycetes

4. Lichens

• Symbiotic association of algae and fungi.
• Fungus dominant algae – Helotism
  • Mitochondria – aerobic
  • Chloroplast – Anaerobic

1. Cructose
2. Foliose
3. Fruticose

5. Bryophytes

• Study of b Bryophytes – Bryology
• Sex organs
  • Archegonia– female sex organ
  • Antheredia- male sex organ

1. Liverworts – Hepaticopsida
2. Hornworts- Anthoceropsida
3. Mosses- Bryopsida

6. Pteridophytes

• Seedless vascular cryptograms
• Botanical snakes

1. Psilophytes
2. Lycophytes – Club Moss
3. Calamophytes- Horse tails
4. Filicophytes- Ferns

7. Gymnosperms

• Naked seeded plant
• Jurassic period

1. Cycadophyta – Cycas – Cycadales 
2. Coniferophyta – Pinus – Coniferophyta
3. Gnetophyta – Gnetum

8. Angiosperms

• These are close-seeded, flowering plants.
  • Monocots 
  • Dicots
• Angio – vessel   Spermae- seed

• A group of fossil Gymnosperms – Caytoria
• A group of fossil Angiosperms – Archaeopteryx
• Fossil of Angiosperm reproductive structure – Arche Fructus
• Fossil of the flower of Angiosperms – Archeanthus
• Separation of the from the parent plant body- Desiminutes

Salient features of Angiosperms

1. Cosmopolitan in distribution – wide/ distant
2. Habit- herb. (advanced), shrub, climber, tree (primitive)
3. Habitat- Xerophytes, Halophytes, Aquatic
4. The plant body is sporophytic differentiated into root and stem. (Root system) underground and Aerial part (shoot System).
5. Stem well differentiated into nodes and internodes with leaves on the nodes.
6. Well-developed Vascular Systems with Phloem & Xylem.
7. Phloem – food conducting tissue with Companion cells and forms passage transport of floral hormones (Florigen).
8. The xylem is water Conducting tissue involved in mechanical support. Lignophytes (Woody plants).
9. The reproductive Structure is the flower. The flower is a modified determinate Shoot for the purpose of Sexual reproduction.
10. Calyx and Corolla are the non-essential organs that help in protection & pollination respectively sex organs i.e. essential organs attracting pollinators.
11. The androecium is a male sex organ which is a collection of Stamens. Each Stamen has an elongated filament ending with anther lobe which has 4-2 microsporangia.
12. Microsporangia produces 2-3 celled pollen-grains are called male Gametophyte
13. The gynoecium is the female Sex-organ is differentiated into pistil ovary, Style, and stigma.
14. Ovules are megasporangia which produces female gametophyte Embryosac celled 8 nucleated Structure.
15. Pollination by many modes for Successful fertilization (Abiotic/biotic)
16. Fertilization (syngamy): Porogamy, Mesogamy, Chalazogamy Double fertilization and triple fusion.
17. Two Sperm cells- One Sperm cell Egg cell. Another Sperm Cell – Two polar nuclei. 
18. (Selective fertilization/ Preferential fertilization:  In which out of two sperm cell which Sperm  cell is fused with which Cells of the female egg cell)
19. Embryo – Product of Syngamy – Sporophyte.
20. Endosperms – Product of triple fusion & usually triploid & divide before Zygote nourishes the embryo.
21.  Podostemaceae, Tropaceae and Orchidaceae have- No Endosperms.
22. Fruit : Simple or complex. developed from ovary.
23. Ethylene- Fruiting hormone.
24. EIS – Ethylene Insensitive Genes.
25. EIR- Ethylene Resistance
26. Seeds – Ovules in these are two cotyledons.
27. Vesselless Angiosperms which do not contain vessels. There are 10 genera of Vesselless Angiosperms
    1. Amborella 
    2. Drimys
    3. Babbia
    4. Exospermum
    5. Zygonum
    6. Tetracentron
    7. Pseudowintera
    8. Trochodendron
    9. Beliolum 
    10. Sarcandra

Plant Taxonomy and Systematics

Taxonomy

• The term taxonomy was first used by a French botanist called A.P. De Candolle.
• In Greek Taxonomy means Arrangement by rules.

Definition

Taxonomy is defined as the branch of science dealing with the study of classification including its basic principles, rules, and procedures. It can also be defined as principles of classification of organisms.

OR

A branch of botany that deals with the study of identification, naming & classification of plants in a systematic manner is called plant taxonomy.

Taxon

• Any unit of classification in taxonomy. 
• First time the word taxonomy was used by the French Botanist-  A-P. de Candole.
• Greek meaning of Taxonomy- Arrangement by rules.

Components of Taxonomy

1. Identification
2. Naming
3. Classification

Identification :

The study of taxonomy identification of plants is done by comparing the characteristics of unknown plants with the characteristics of known plants.

Naming:

a) Common name:  The common name varies from place to place or region to region/country to country. Common names lead to confusion. 

Examples: Mango, Jackfruit, Guava, Coconut, areca nut, teak etc.

b) Scientific name: The naming of a plant in a scientific manner or method is called the scientific name or botanical name. 

• Each scientific name or botanical name consists of two Latin words. 
• The first Latin word indicates a Generic name and the second Latin word indicates a specific name. Examples:  Solanum melongena (brinjal), Solanum tuberosum (potato), Ficus bengalensis (Fig), Agave mexicana, Agave americana etc.
• The generic name starts with a capital letter & the specific name starts with a small letter.
• In the scientific name, the genera or species always denotes the name of the discoverer or the name of the place or special character of that plant.

Binomial nomenclature:

Binomial nomenclature was first introduced by ‘Carl Linnaeus’ a Swedish botanist. According to ‘Carl Linnaeus, each plant has two names, one is a generic name & the other is a species name. This is called Binomial Nomenclature.

Classification:

This is the third component of taxonomy. Classification is assigning a plant to a particular division or class or order or family.

Difference between Traditional Taxonomy and Modern Taxonomy

Traditional Taxonomy

Also known as Alpha, Classic or Formal Taxonomy.

1. Field Study
2. Herbarium Study
3. Library description
4. Theoretical aspects

Modern Taxonomy

Also known as Omega, Experimental, Holo Taxonomy.

1. Lab Experiments
2. Computerized Assistance
3. Analytical
4. Molecular
5. Evidence

• Modern Taxonomy (taxonomy with phylogeny)
• Traditional taxonomy

Types of Taxonomy

Alpha taxonomy :

It is nothing but a classification which is entirely based on morphological characters. It is also called Classical, Orthodox, Formal or Descriptive taxonomy. This includes the Gastrorates pioneer, Consolidation phase. It is the taxonomy of the 19’s Century. It is a predominantal System and also called as horizontal classification, which includes the classification of Linnaeus, Bentham & Hooker,  AD Candole, Adelson.

Beta Taxonomy (Higher Categories):

Macro taxonomy, Mays 1963. It is nothing but the arrangement of species into a higher archeal System of higher categories or taxa. It is developed during 20th Century it is also called as Biosystematics or new systematics which includes the classification Biosystematic phase 

Gamma taxonomy: 

Gamma taxonomy is nothing but the Taxonomy of populations with phylogenetic trends and are included in the  with regard to origin & development of Species with fossil evidence. This also comes under the biosystematic phase. It was also developed during the 20th Century.

Omega Taxonomy:

It is also called modern taxonomy, Synthetic Taxonomy, Experimental Taxonomy, Holo Taxonomy.  Omega Taxonomy is nothing but taxonomy with classification are based on the widenss with relevant data from all the branches of Botany Which includes Morphology, Anatomy, Embryology, Cytology, Phytochemistry, Ecology, Palynology, Physiology, Paleontology, Serology and Molecular biology which includes chemistry, evidences from all are taken into account to trace the phylogeny and relationship of plant taxa then it is known as Omega temonomy or Holo Taxonomy.

Since the evidence is taken from different origins/ branches of botany defined as an ultimate perfect system based on all available characters taken from the Alpha Beta, Gamma Taxonomy into account.

This is 21st Century Systems of classification and also -particularly 20th System of classification.

It is equivalent to the Biosystematic & Synthetic phase.

 Ex: Systematic classification by Hutchinson, Thomey, Bersey, Eureto. APG 3 to 4 Adelson.

Serotaxonomy :

 It is also called Immuno taxonomy. Carlmez (1926) Conducted a test to know the relationship between different plant species. This is also known as Serotoxonomy Serodiagnosis. [immunotaxonomy]. This test is an indicator of plant relationships and this test was conducted at the University of Koenisbagh.

In this test protein extract is made from a plant A and is injected to the Rabbit after that he was waited for 30days in order to allow the rabbit body to react to the foreign protein, then the blood Serum is drawn from the rabbit & its mixed with protein extract of the plant B whose  relationship with plant A are to be tested. 

In this test if the precipitation is formed then the relationship is indicated. If the precipitation is not from then no relationship is indicated. If the precipitation is formed even after the high dilution of Serum then the relationship is considered as closer and compared with Serum is less diluted.

Systematics

Systematics refers to the study and classification of organisms for the determination of the evolutionary relationship of organisms. It includes classification, naming, cladistics, and phylogenetics.

OR

It is also defined as the study of all kinds and diversity of all organisms and any or all relationships between them.

• Systematics can be defined as the study of all kinds and diversity of all organisms and all relationships between them – discovered by Simpson (1963).
• Raven et al (1976), Systematics is the scientific study of the kinds and diversities of organisms and of relationship among them.
• In 1986 Radfold, Systematics is the study of phenotypic, Genetic and phylogenetic relationship among taxa.

Taxonomy and systematics are both used to identify, classify organisms. Taxonomy comes under systematics where it involves the identification, naming and classifications of the organism. But Systematics involves the evolutionary relationships of the organisms along with the taxonomy.

Objectives and goals of Systematics

Objectives:

1. To prepare a scheme of classification that provides a phenetic, natural or phylogenetic relationship among taxa.
2. To establish suitable method for identification, nomenclature and description of taxa
   1. ICBN: International Code for Binomial Nomenclature
   2. 2013 ICN – International Code for Algae, Fungi and Plants nomenclature
3. To provide an inventory of plant taxa that Surts Local, regional and Continental needs.
4. To create an understanding of the evolutionary process.
5. To train students of Plant Sciences with regard to the diversity of organisms & their relationship with other biological branches.

Goals:

1. To acquire fundamental Values of plant Systematics.
2. To know about the basic concepts and principles of Plant Systematics.
3. To know about the basic concepts and principles of Plant Systematics
4. To be aware of the importance of taxonomic relationship and Plant Systematics.
5. To develop a knowledge of applicability of plant systematic studies.

Future Perspectives in Plant Systematics

1. New discoveries
2. Monograph
3. Revision of old classification with new distribution.
4. Exploration of several unknown floristic areas
5. Re–evaluation of old taxonomic fields.
6. Using mathematical logic to understand relationships among taxa.
7. Disputed taxa to be placed properly.
8. Introduction of new crops with knowledge of genetic diversity.
9. Using molecular markers nucleic acids and Proteins, DNA’s, Isozyme and other markers to understand relationships.
   1. Mitochondria, chloroplasts – DNA
   2. Sementides- DNA protein and_ RNA production of Secondary Metabolites (Medicinally used).

Phases of Development of Classification

1. Exploratory phase (pioneer phase)
2. Consolidation phase
3. Biosystematic phase
4. Encyclopedic phase/ Synthetic phase/ Holo taxonomic / experimental phase

Exploratory Phase (pioneer phase): 

This is an initial phase during this phase discovery classification, naming, identification of plants were undertaken.

Consolidation phase : 

During the consolidation phase synthesis of characters mostly based on gross morphology feed and herbarium knowledge, preparation of flora, manuals, monographs and form based classification System were undertaken.

Bio-systematic phase:

During this phase analysis of the breeding system, chromosome number, morphology, behaviour of chromosome during meiosis and mitosis were undertaken to classify the plants.

Encyclopedic phase:

During this phate analysis and synthesis of all information from previous phases & various fields of botany i.e. Morphology, Anatomy, Cytology, Palynology, Embryology, Chemistry, Ecology, Breeding, Physiology, Host and parasite relationship and developmental aspect were taken into account including molecular aspect to develop evolutionary and phylogenetic system of classification.

Taxonomy vs Systematics differences:

FAQs: