1. Different branches of plant science
and their application to
agriculture
- Bhrigupoti Hazarika, M.Sc
(Botany)
2. Introduction
• Plant science (or Botany) is the study of
organisms in the kingdom Plantae, otherwise
known as Plants.
• The word Botany comes from the Ancient
Greek word botane, referring to plants,
grasses and pastures. One who studies botany
is called as botanist.
3. Botany research can be broken down into catagories based on what
subcategory of Biology the research is based in. for example,
Botanists may study –
• Plant anatomy
• Plant genetics
• Cytology (the study of cells- in this case plant cells)
• Ecology
• Biochemistry
• Biophysics
• Plant taxonomy
• Physiology
• Microbiology
• Molecular biology
• Paleobotany (the study of plant fossils)
4. Besides these applied Plant sciences are also
there. And these categories are often related to the
uses of Plants, such as agriculture. They include-
• Agronomy – crop and soil science
• Food science
• Forestry
• Horticulture – the production of ornamental
plants and crops
• Natural resource management
• Plant breeding
• Plant pathology – the study of plant diseases
5. PLANT ANATOMY
• Plant anatomy is the study of the shape,
structure and size of plants. As a part of botany
(the study of plants), plant anatomy focuses on
the structural or body parts and systems that
make up a plant. A typical plant body consists
of three major vegetative organs – the root, the
stem and the leaf as well as a set of
reproductive parts that include flowers, fruits
and seeds
6.
7. Plant Genetics
• The branch of biological science which deals with the heredity
and variation is termed as Genetics.
• The process of transmission of characters from one generation
to another through the gametes of organisms is called as
heredity or inheritance.
Genetics plays an very important role in the development of
modern agriculture. Some of the most important points are-
• Success in production of new varieties of crops
• High yielding varieties of plants
• Seedless fruits (like seedless Banannas)
• Yielding food products with high nutritional values
• Disease resistant
• Frost resistance
• And making of other stress resistant varieties of plants etc.
8. Role of Mutations in improvement of
crops (plant breeding)
• One most common and frequent word used in
Genetics is Mutation.
• Mutation is a sudden appearance of marked
heritable change in the characteristics of an
organism. Processes like gene mutation,
chromosomal aberration, polyploidy and
recombination generate variations in a
population. Variation and selection are
essential for evolution of species.
11. Besides these Polyploidy and Allopolyploidy also helps in
improvement of crop species
Characteristics of polyploidy plants :
• Polyploidy increases the size and vigour of the plants.
• The products of polyploidy plants are better in quality, taste,
nutritional value, sugar contents, vitamin contents etc.
• Many polypolid plants are disease resistant, drought resistant
and resistant to other stresses.
• Polyploidy helps in production of seedless varieties of many
fruits like apples, water-melons, tomatoes, plums etc.
• Polyploidy generates variations which help directly in evolution.
It is considered as aquick process of evolution of new species.
• Origin of many species and their inter relationship can be traced
with the help of polyploids. The allopolyploids suggest how
new species have arisen by crosses between two species.
• o helps in improvement of crop species
12.
13. Ecology
• The agricultural system has depended mainly on
internal resources, recycling of organic matter,
built in biological control mechanisms, and
natural rainfall patterns.
• The cultivation of different types of crops over
the years on the same land also suppressed
insects, weeds and diseases by effectively
breaking the lifecycles of these pests. This type of
farming linking agriculture to ecology, commonly
called as ecology farming.
• Ecology plays the most significant role in
agriculture because different nutrient cycles (like
carbon, nitrogen, sulphur, phosphorus )
14.
15. Biochemistry :
• Prevent diseases and enhance yield/growth. It helps for
prevention, treatment of diseases and also increase the
production or yield. Some hormone promote growth,
while other promote flowering, fruit formation etc. in
fisheries, use of substances to promote fish growth, their
growth, their reproduction etc can be understood.
• Adulteration : Even the composition of food material
produced, their alteration or adulteration for example in
honey can be found by biochemical tests. Biochemistry
tests help prevent contamination.
• Biochemical tests for the pesticide residues or other toxic
waste in plants, food grain and soil can be evaluated.
Hence during import and export of food grains a
biochemical check of the toxic residues is done to fix the
quality.
•
16. • In animal husbandary, the quality of milk can be checked
by biochemical tests. It also helps diagnose any disease
condition in animals and birds.
• In fisheries the water quality is regularly monitored by
biochemical tests. Any drastic change in water chemistry
& composition of fishery ponds can lead to vast death of
fishes and prawns, hence the tests are done on regular
basis to see salt content (calcium content), Ph,
accumulation of waste due to not changing water for
long etc.
• In Plant/Botany : Biochemistry of plants gave way to
breakthrough of how food is synthesized in them and
the reason why they are autotrophs i.e. not dependent
on other living beings for food. Biochemistry in plants
describes; photosynthesis, respiration, different sugars,
plants secondary metabolites etc.
17. Biophysics
• Many results from scientific researches on
seed or plant radiation with UV-rays and
gamma rays, ultrasound and ionized radiation
show distinct effects on growth and
development of plants.
• In agriculture, forestry, food technologies He-
Ne lasers are also used.
18. Effect in agriculture with biophysics
methods
• Increased seed germination from 20 to 35%
• Decreased seed rates upto 30%
• Increased root mass up to 24%
• Increased vegetative mass from 10 to 45%
• Increased yield from 10 to 50%
• Increased resistance to outside influence (drought,
frost etc)
• Increased resistance to pests and diseases
• Better qualitative characteristics of products (protein,
sugar, vitamins and another useful metabolites)
19. • Decreasing mineral fertilizers from 10 to 15%
• Decreasing application of pesticides
• Accelerated maturing
• Safer products with higher quality
• Decreasing of underground and surface water
pollution
• Low price of application
• Repeated positive effects at any soil and
climate conditions and on different cultivars
• Decreasing of producer price of products
20. Plant taxonomy :
• Taxonomy is a science or part of biology which involves
naming, identifying and classifying organisms.
• It holds agricultural importance because of the ability
for plant pests, weeds and pathogens identification.
• Since almost all these causative organisms fall under a
similar group, the manifestation of pesticide or
biological control can be done accordingly.
• Plant taxonomy plays a pivotal role in identification of
wild relatives and land races of our cultivated crops
confined to restricted localities or to certain ethnic
groups
21. Microbiology :
• Agricultural microbiology is a branch of
microbiology dealing with plant-associated
microbes and plant and animal diseases.
• It also deals with the microbiology of soil fertility,
such as microbial degradation of organic matter
and soil nutrient transformations.
• Again from various naturally occurring
microorganisms such as bacteria and fungi can
protect crops from pests and diseases and
enhance plant productivity and fertility.
22. Importance of soil microorganisms :
• Involved in nutrient transformation process
• Decomposition of resistant components of
plant and animal tissue
• Role in microbial antagonism (example DAP,
UREA, SUPER PHOSPHATE etc)
23. Molecular biology (Biotechnology)
• biotechnology is the application of scientific and engineering
principles to the processing of materials by biological agents to
provide goods and services.
• The area of study in biotechnology is a vast one and on the basis of
area of interest, its working fields can be grouped into several kinds
like –
• DNA biotechnology or genetic engineering
• Microbial or Fermentation biotechnology (Industrial biotechnology)
• Cell biotechnology
• Medical biotechnology
• Mining and metal biotechnology
• Agricultural biotechnology
• Enzyme biotechnology
• Energy production biotechnology
• Marine biotechnology
• Veterinary biotechnology etc.
24. • But here we will discuss about the application of
biotechnology in agriculture.
• Bacillus thuringiensis, a bacterium produces a protein that
is toxic to insects. The gene for this toxic protein is known
as Bt gene. The Bt gene has been isolated from the
bacterium and transferred to tomato, cotton plant etc.
making them resistant to insects.
• Transgenic tobacco plant with Bt2 gene exhibits resistance
against Mendusa sexta, an insect. When the larvae of this
insect consume the leaves of the tobacco plant, 75 to
100% larvae die to toxic effect of the said plant.
• It is also found that when Bt gene of B. thuringiensis
inserted into Pseudomonas fluorescence and inoculated
into soil, it could cause death of cut worms.
25. • Phaseolin is a major protein in French bean, but its value is
reduced due to methionine content. The phaseolin gene
from French bean (rajma) was successfully transformed to
cultured cells of sunflower. The callus producing bean
protein is known as sunbean. Moreover, this phaseolin
gene can be reintroduced into the bean plant which
enhance the nutritional value of the crop.
• Glyphosphate is a herbicide but it kills both unwanted
weeds and also the useful crops. The gene for glyphosphate
synthesis is found in Salmonella typhimurium, a bacterium
and a mutant strain of S. typhimurium is resistant to
glyphosphate. This mutant gene was first cloned to E. coli
and then recloned to Agrobacterium tumifaciens via T1
plasmid. Introduction of T1 plasmid with glyphosphate
resistance gene into crop plants like cotton, tobacco, maize
etc. become resistant to this herbicide (glyphosphate).
