Table of Contents
- What is Botany?
- History of Botany
- Branches of Botany
- 1.Systematic Botany
- 2.Anatomical Botany
- 3.Morphological Botany
- 4.Plant Physiology or physiological Botany
- 5.Plant Pathology
- Plant Pathogens
- Physiological Plant Disorders
- 6.Plant Ecology
- 7.Plant Genetics
- 8.Plant Cytology
- Careers in Botany
- Importance of Botany
What is Botany?
Botany is the scientific study of plant life. This branch of biology capture a broad range of scientific fields. In addition, the word botany is coined from the adjective botanic, which comes from the Greek word botanē. Therefore the study of botany deals with plant structure, growth, and diseases. Also, it takes a closer look at plant metabolism. With a view on ecology, evolution, and development. Again with over 410,000 species of terrestrial plants, the need for plant classification is also in the purview. The one who specializes in the study of botany is called a ”Botanist”. Botany is one of the oldest fields in natural sciences.
History of Botany
Since before the antediluvian, humans have been curious and interested in the major source of life. Hence the curiosity to study about plants, because they provide us with food, oxygen, and a variety of raw materials.
The father of Botany known as Theophrastus. He is a Greek scholar and one of the pioneers in botany, wrote some books. Firstly he wrote on “Enquiring into Plants” which portrayed a classification system based on geographical ranges, sizes, uses, and growth patterns. Secondly, he wrote “on the causes of plants” explained as the economics of growing plants.
Another Greek that made great strides as early as 90-40 A.D was Dioscorides a physician by trade. He wrote a book known as “De Materia Medica” which is an encyclopedia about herbal medicines. Therefore he developed a classification system based on medicinal, and culinary, or aromatic value. It was a guidebook for over 1000 years.
The scientific innovation of the compound microscope in 1665 by Robert Hooke, opened a new way for botany. Therefore we can now view and study the anatomy and physiology of plants. Furthermore, the discovery of the green pigment called chlorophyll aided in the understanding of the process of photosynthesis. In addition to such a magnificent discovery, a scientist named Gregory Mendell opened a new field of plant genetics. With his studies and experiment on the genetic inheritance of pea plants.
And Carl Linnaeus in 1753 published a book named species Plantarum. It contained 6000 plant species. And establishing the binomial nomenclature, a system used in naming living things.
Branches of Botany
There are many disciplines and sub-disciplines in botany. Therefore, based on plant form and function, the major branches or disciplines are categorized into 8. These disciplines are Systematics, Anatomy, Morphology, physiology, Genetics, Pathology, Cytology, and plant ecology. A review of the branches hereafter.
This deals with the study of plant characteristics. With regards to decerning their evolutionary trend or history and finding the different phylogenetic associations of plants. In addition, it works by shuffling or dividing plants into taxonomic groups. This is based on anatomical, embryological, chromosomal, morphological, and chemical parameters. Furthermore, its primary goal is to document the evolutionary history of a group of plants.
The classification system for systematic botany
The criterion used for grouping plants includes; cladistics, phenetics, and phyletics.
Cladistics; deals with the evolutionary trend or history of plants, in order to be classified into a taxonomic group. Also, the evolutionary pattern of descent is represented on cladograms or family trees. Again, the maps (cladogram) show a common ancestor of species from which they evolve over time.
Phenetics; Deals with the use of physical characteristics of plants or plant traits to classify plants. Unlike evolutionary history used in Cladistics. A good example of this system is the classification of plants by Linnaeus.
Phyletics; This system suggests that new species surface or arise gradually naturally. Thus it does not conforms to evolutionary history nor physical characteristics. Furthermore, it is deemed as the most natural approach to classification in systemic botany.
Commonly referred to as plant anatomy or phytotomy is the study of a plant’s internal structure. With the advancements in technology, the investigation of plant anatomy is on a cellular level. And it involves the sectioning of tissues and microscopy.
the categories used in the division of plant anatomy are namely; flower, leaf, stem, fruit/seed, and wood.
- leaf structure
- stem structure
- Bark; (cork, phloem, Vascular cambium)
- Heartwood and sapwood; (Branch collar)
- Ovule; (seed structure)
- Accessory fruit
Also known as plant morphology or phytomorphology. This is the study of the external or physical structures of plants. This is a useful field in the visual identification of plants. Therefore, there are 4 key areas of investigation in this branch, namely; Comparative investigation, Vegetative, and reproductive structures, plant growth and, plant development.
A comparison of different plants of the same or different species is made. And this is done in order to answer the question of why the structures are similar. Also, it can be said that the causes leading to the similarity in appearance, could be either genetics, physiology, or a response to environmental factors. Therefore, the causes can be categorized as either homology or convergence.
These are the structures that are similar between two species, that resulted from a common ih=nherited genetic pathway or shared ancestry. For example, the leaves of pine, cabbage, and oak all look different but share basic arrangements and structures of their parts. Thus, because of shared ancestry or the same genetic inheritance.
These are the structures that are similar between plant species, that resulted from their adaptation to the same environmental pressure. For example, the stem of Asparagus setaceus and the frond of Bryopsis plumosa, have the same appearance of feathery branching. With one being a flowering plant and the other an algae. Hence, this phenomenon is possible because of the same environmental factors that have pressured their adaptation.
Vegetative and Reproductive characteristics
The vegetative and reproductive plant structures are treated in plant morphology. In fact, in vascular plants, the vegetative (somatic) structures include 2 main organ systems. Namely;
- Shoot system comprising of stems and leaves.
- Root system
These systems are similar in almost all vascular plants. Hence they provide a goal for plant morphology study.
On the other hand, the reproductive structures vary from plant to plant and are mostly specific to particular groups of plants. Structures like seed cones that are found exclusively in conifers and other gymnosperms, along with flowers and fruits are only found in angiosperms. On a whole, because of the variations in reproductive structures, than in vegetative structures, it is therefore suited for plant classification.
Importance of Vegetative and Reproductive characteristics
- Use in the identification of plants using qualitative and, quantitative characteristics
- Helps in the understanding of alternation of generations in plants
- Aid in the understanding of pigmentation in plants.
This is the process that leads to the origination, maturity, and growth of plant structure. This process differs from that of vertebrate animals, whereby an embryo develops all the body parts before the organism’s birth or hatch. In contrast, plants continue to produce new tissues and structures throughout their life span. Thus living plants always possess embryonic tissues located at the meristem of plants (located at the tips or between mature tissues of a plant.)
The beginning of a vascular plant starts from the single-celled zygote, formed during fertilization of fertile egg cells by a sperm cell. Hence resulting in the initiation of embryogenesis. This process gives plants the basic structures to start life. Afterward, the plant goes through the production of new and additional structures like leaves, shoots, and roots a process known as organogenesis. Furthermore, the plant can undergo cell elongation as another growth mechanism.
4.Plant Physiology or physiological Botany
This sub-discipline of botany is concerned with plant physiology and function. It comprises the study of all the internal activities of plants. Hence a study of the physical and chemical processes associated with a living plant. Therefore, in order to grasp the concept of plant physiology, it has been divided into several main areas of research. Namely;
- Biochemistry of plants
- Constituent elements
- Signals and regulators
- Environmental physiology
Biochemistry of Plants
In order for plants to adapt to their environment, they produce a large volume of chemical compounds that has unusual properties. These chemical properties are similar to the ones produced by animals. The only difference is the level of molecular arrangement of the basic atomic components. Therefore, these components include oxygen, carbon, phosphorus, hydrogen, calcium, and many other elements.
Thus, these chemical properties are extracted for commercial purposes. For example, the pigment in plants is extracted and used in the production of dye. Also, some of these plants have pharmacological potential that is also extracted and used in drug production.
Plants need some elements called nutrients in large quantities (macronutrients) and some in trace amounts (micronutrients) for a healthy and productive life. These nutrients are absorbed in the form of ions and taken from the soil through the rooting system or cit can be taken from the capture of prey as in the case of carnivorous plants.
The subsequent table shows the list of essential nutrients to plants.
Form of Uptake
Various organic compounds
Various organic compounds
Various organic compounds
Nucleic acids, proteins, hormones, etc.
Nucleic acids, phospholipids, ATP
Constituent of proteins and coenzymes
cofactor in protein synthesis, water balance, etc.
Membrane synthesis and stabilization
An element essential for chlorophyll
Form of uptake
Involved in the synthesis of enzymes and chlorophyll
The activity of some enzymes
Enzymes for lignin synthesis
Nitrogen Fixation, reduction of nitrates
Enzymatic cofactor in the metabolism of nitrogen compounds
Pigments are one of the most important plants molecule required for plant function. These pigments, selectively absorb a certain wavelength of light and reflect other wavelengths in the process. Hence the absorbed wavelength is used to power the chemical reactions of the plant, and the reflected wavelength gives the plant color that the human eye can see.
In fact, the basic pigments found in plants are chlorophyll, carotenoids, and anthocyanins.
This is the primary pigment in plants, hence it is a porphyrin that absorbs blue and red wavelengths while reflecting green to the eye. Its main function is to fuel photosynthesis, by intercepting and absorbing light rays.
These are added pigments in plants that are red, orange, and yellow in color. They function by helping the plants to capture wavelengths of light that are not readily absorbed by chlorophyll. Thus the captured light also aids in photosynthesis. Therefore, some notable carotenoids are carotene (found in carrots, and is the cause of the orange color), lycopene (red pigment found in tomatoes), and lutein (yellow pigment found in fruits and vegetables). Carotenoids are known to improve healthy human eyesight by acting as antioxidants.
These are pigments that appear blue – red on the basis of pH. Hence they are water-soluble flavonoid pigments. They are responsible for the colors in higher plant structures (leaves, stems, roots, flowers, and fruits). Its effects are seen mostly in the color of flower petals.
Signal and Regulators
Plants produce chemicals that trigger certain growth habits in them. These chemical signals and regulators can either be in the form of plant hormones or photomorphogenesis.
These are chemical stimuli produced by plants in trace amounts, in order to influence growth development and differentiation of cells and tissues. Therefore, they affect plant growth processes from dormancy, germination, flowering, and seed development. hence they are vital in plant growth. Furthermore, they influence upward and downward movement of plant structures, and also stem development, leaf formation, fruit development, and ripening, as well as leaf abscission and plant death.
Some notable and useful plant hormones are listed below;
- abscisic acid (ABA)
The sensitivity of a plant to light plays an important role in controlling plant structural development. Hence the use of light to control this structural development is termed photomorphogenesis. Specialize receptors are needed which are chemical pigments that absorb specific wavelengths. Therefore these photoreceptors are namely; Phyotchrome, Cryptochrome, UV-B receptor, and Protochlorophyllide a. A good example of photoreceptors in action is the phytochrome that necessitates photoperiodism in flowering plants.
This is a sub-discipline that deals with plants’ response to physical environmental factors, such as rain, temperature, wind, fire, and the exchange of gasses in the atmosphere. Furthermore, a response to the biological factors is also examined, for example, herbivory, disease, parasitism, and competition. also mutualism, and pollination. In addition, the phenomenon of tropism and nastic movements are considered. Therefore, tropism is a directional stimulus or movement by plants to certain environmental parameters like gravity and sunlight. Whereas nastic movements are responses to a non-directional stimulus such as temperature, or humidity, or turgor pressure. An example of nastic movement is the response of the venus fly trap plant to touch.
Also known as phytopathology, is the scientific investigation and study of plant diseases caused by infectious organisms called pathogens and physiological factors known as environmental conditions. Again, it gives an in-depth review of the disease triangle. The principle or concept is based on the idea that disease is a result of an interaction between a host, a pathogen, and an environmental condition. In fact, organisms that cause infectious diseases include fungi, bacteria, viruses, viroids, virus-like organisms, nematodes, and parasitic plants.
Plant pathology includes the study and identification of etiology, disease circle, economic impact, epidemiology, effects of disease on humans and animals, and management of plant disease.
Most plant pathogens fall in one of the following categories listed below;
- Phytoplasma and Spiroplasma
- Viruses, viroids, and virus-like organisms
- Parasitic Plants
Fungi and Fungi Like Pathogens
A large number of fungal pathogens belong to the Ascomycetes and Basidiomycetes. They produce spores either sexually or asexually, that can be spread in the air, through water, or in the soil. Fungicides are used in controlling fungal disease, but a checkmate needs to be put in place to reduce or avoid the emergence of resistant pathogens.
Examples of Fungal Pathogens
- fusarium spp
- verticillium spp
- Thielaviopsis spp (causes black root rot and canker rot)
- Rhizoctonia spp
- Puccinia spp (causes severe rusts in cereal grains and grasses)
This is a fungal-like pathogen that is of the genus Phytophthora, which is very destructive to plants. Examples are Pythium spp and Phytophthora spp.
Majority of the bacteria that are known to cause diseases in plants are saprotrophic. Therefore, they do not harm the plants. But some 500 species affect plants and are mostly rod shape (bacilli) in order to colonize the plant cells.
These bacteria possess 4 key pathogenicity that enables them to invade plant cells. and they are listed below;
- cell wall degrading enzymes
Examples of Bacterial Pathogens
- Xanthomonas spp
- Pseudomonas spp
Phytoplasma and Spiroplasmas
These are a genre of bacteria that do not possess cell walls. Hence, they tend to have smaller genomes than true bacteria. And also, they are transmitted by sap-sucking injects through the plants’ phloem and it reproduces.
Viruses, Viroids, and virus-like organisms
These are single-stranded RNA genomes that encode 3 or 4 proteins namely; a replicase, a coat protein, a movement protein, and sometimes a transmission protein by a vector. Truly, they are usually asymptomatic and affect mostly plant yield. Again, they are transmitted by a vector from plant to plant.
These are multicellular worm-like organisms that live in the soil and affect the root system of plants. They are either cyst nematodes (affect few plant species) or root-knot nematodes (affect a broad range of plant species). Thus, they affect the plant by causing radical changes to the root cells, in order to meet up with their lifestyle.
These are root invading pathogens that can sit dormant in a zoospore for many years until it comes in contact with root hairs. Also, they can transmit viruses to plants and then produce plasmodium to invade the plant.
These are plants like dodder and mistletoe which are good examples of parasitic plants, that serve as a conduit for the transmission of viruses or virus-like organisms.
Physiological Plant Disorders
These plant disorders are categorized under natural plant disorders and man-made disorders.
Natural plant physiological disorders
- Nutrient deficiency
- flooding and poor drainage
Man-made plant physiological disorders
- soil compaction
- pollution of water, soil, and air
- excess application of herbicide
- salt (winter road salt application)
- lack of education and training for farmers and people working with plants
Plant Disease Management
There are 6 ways or methods in the approach to managing plant disease from becoming an outbreak or a global pandemic resulting in a shortage of food and reduction in biodiversity. The six methods are as follows;
- Plant resistance
This is the study of plant relationships with their environment or habitat. Therefore the ultimate goal of plant ecology is to study and understand the causes of plant distribution patterns, productivity, environmental impact, evolution, and plants’ response to environmental changes.
Thus, there are different facets of plant ecology, namely;
It focuses on individual plants and how they are affected by the environment
This focuses on plant communities and how they are influenced by the environment and also how the environment feels their impacts.
Focuses on the numerical side of plants and hence their distribution
This focuses mainly on plant distribution across the globe.
Plant ecologist needs to be aware and pay constant attention to the changes that involve the interaction between plants and their environment.
Ever since the experiment of Gregory Mendel on the shape of Pisum sativum (peas), there has been a downpour of knowledge in the world or field of genetics. In-plant genetics, one can see how plants transfer their genes to new plants, and how plants can be crossbred to form a new species. For example, peppermint is a mixture of Mentha aquatica and Mentha spicata.
Therefore this is the study of hereditary genes, gene function in plants and also it is divided into molecular genetics which gives greater insight into cells and chloroplast, and epigenetics, which studies heritable changes in gene function in order to throw more light on the underlying DNA sequence. An example is the determination of express or non-express genes through changes in genes marked by DNA methylation.
This is a branch of botany that deals with everything pertaining to plant cells. Therefore it is overlapping with other branches like genetics, physiology, and systematic botany.
In addition, to the major disciplines or branches in botany, there are several subdisciplines that have been developed for convenience and expertise. Among them are mycology (the study of fungi), phycology (the study of algae), bryology (the study of mosses and liverworts), pteridology (the study of ferns and their relatives), paleobotany (the study of fossil plants), ethnobotany (study of the traditional use of plants by locals, now and in past), and palynology (the study of modern fossil pollen and spores, with special reference to their identification).
Careers in Botany
Your love for plant life will increase your drive to becoming an expert in any of the fields. The knowledge gained from the study of plants has a wide spectrum of its application in the preservation of human life and the natural world. Here are some of the basic careers in plant science you can get with a bachelor’s degree.
- Plant Geneticist
- Field Botanist
- soil scientist
- greenhouse manager
- propagation scientist
- plant journalist
- plant champion
Depending on your level of qualification and expertise, botanists do earn approximately, $ 33,000 to $103,000 per annum. the average salary for most botanists is approximately $60,000 per year.
so get a niche in botany and go wild in becoming the best in your chosen field!
Importance of Botany
Part of the fundamentals of life forms on earth is; plants. They produce a whole lot of benefits such as food, fibers, fuel, medicine, and through the ability of plants to photosynthesize, they absorb carbon dioxide a greenhouse gas and give out oxygen in the process.
This importance can be categorized into 4 namely;
Most of the food we consume comes from plants either directly or indirectly. They are the first line of food production through photosynthesis. Understanding the importance of plants in food production can help us gain food security for the next generations
To understand fundamental life processes
Gregory Mendel used a plant to understand genetics, that experiment enabled us to grasp the field of genes in plants, animals, and humans. A closer look at the cell and physiological research has opened our understanding of nutrient cycles such as carbon, nitrogen, and potassium. In addition, we now have an understanding of C3 and C4 photosynthetic plants.
Utilize medicine and materials
Most of our medicine is extracted from plant chemical compounds. For example, Aspirin from the bark of a willow tree and nicotine from tobacco. Also, the field of pharmacology is dedicated to researching and finding new plants with medicinal and toxic derivatives. Furthermore, many natural materials are provided by plants, such as cotton, rubber, lumber, vegetable oils, wood, paper, rope, and linen.
Understand environmental changes
Plants have the ability to detect and help us understand environmental changes. Such as understanding plant life cycle can aid in climate-change research, destruction of habitat can reduce the animal population which leads to the extinction of species, plants response to ultraviolet rays helps us understand ozone layer depletion. They also help in storing carbon dioxide which is a greenhouse gas that affects the ozone and causes global warming. Furthermore, they can act as bio-indicators to changes in the atmosphere due to pollution like lichens.
On the whole, the importance or benefits of plants cannot be over-emphasized. It is the base of living and a source of aesthetic pleasure from the environment. It helps to preserve biodiversity, maintain ecological and ecosystem functions.