A presentation about plant growth could cover a variety of topics, including the different stages of plant growth, the factors that affect plant growth, and the ways in which plants can be grown and cultivated. The presentation could begin by discussing the basic biology of plants, including their structure and the processes that take place within them. It could then move on to discuss the different stages of plant growth, from germination to maturity, and the factors that affect plant growth, such as light, water, nutrients, and temperature

2. Development of a mature plant from a zygote (fertilised egg)
follow a precise and highly ordered succession of events
The first step in the process of plant growth is seed germination
Growth can be defined as an irreversible permanent increase in size of an organ
or its parts or even of an individual cell. Generally, growth is accompanied by
metabolic processes (both anabolic and catabolic), that occur at the expense of
energy
Plant Growth Generally is Indeterminate
Growth in plants is open, i.e., it can be indeterminate or determinate
form of growth wherein new cells are always being added to the plant body by
the activity of the meristem is called the open form of growth

3. Growth is Measurable
• Growth is, therefore, measured by a variety of
parameters such as increase in….
• Fresh weight
• Dry weight
• Length
• Area
• Volume
• Cell number
• One single maize root apical mersitem can give rise to
more than 17,500 new cells per hour
• Cells in a watermelon may increase in size by upto
3,50,000 times
• Growth of a pollen tube is measured in terms of its
length
• Growth of a leaf is measured in terms of surface area

4. Phases of Growth
Meristematic phase
• Cells in this region are rich in protoplasm, possess
large conspicuous nuclei. Their cell walls are
primary in nature, thin and cellulosic with
abundant plasmodesmatal connections
Phase of elongation
• Increased vacuolation, cell enlargement and new
cell wall deposition are the characteristics of the
cells in this phase
Phase of maturation
• Cells of this zone, attain their maximal size in
terms of cell wall thickening and protoplasmic
modifications

5. Growth Rates
Arithmetic growth is exemplified by
a root elongating at a constant rate
The geometric growth
is a characteristic of living organism
growing in a natural environment

6. Measurement and the comparison of total growth per unit time is
called the absolute growth rate
The growth of the given system per unit time expressed on a
common basis, e.g., per unit initial parameter is called the
relative growth rate
• Water provides the medium for
enzymatic activities & helps in
extension growth of cell
• Oxygen helps in releasing
metabolic energy essential for
growth activities
• Nutrients (macro and micro
essential elements) are required
by plants for the synthesis of
protoplasm and act as source of
energy

7. DIFFERENTIATION, DEDIFFERENTIATION
AND REDIFFERENTIATION
Plasticity
• Plants follow different pathways in response to environment or phases
of life to form different kinds of structures
• Heterophylly in cotton, coriander and larkspur(leaves of the juvenile
plant are different in shape from those in mature plants)
• Buttercup(Leaves inside water and towards air are different)

8. PLANT GROWTH
REGULATORS
• Indole compounds (indole-3-acetic acid, IAA)
• Adenine derivatives (N6 -furfurylamino
purine, kinetin)
• Derivatives of carotenoids (abscisic acid, ABA)
• Terpenes (gibberellic acid, GA3 )
• Gases (ethylene, C2H4)
PGR with growth promoting activity – Auxin, Gibberlin & Cytokinin
PGR with growth inhibiting activity - ABA
Ethylene has both the activity, but it is largely an inhibitor of growth activities

9. PLANT GROWTH REGULATORS-
Functions
• Cell division
• Xylem differentiation
• Herbicide activity(2,4-D)
• Rooting in stem cutting
• Abscission – prevent - young leaves & fruits
Promote - older leaves & fruits
• Parthenocarpy (Tomato)
• Apical dominance
• Pineapple flowering
AUXIN
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10. • Malting process in brewing industry(seed germination)
• Delaying of senescence
• Apple – elongation & shape improvement
• Bolting in rosette plants
• Sugarcane stem elongation(increasing the yield as 20 tonnes per
acre)
• Conifers – fasten maturity period and early seed production
• Lengthening of stalk of grape
GIBBERLIN
Malathi Das applied for BSC L.S
• Gibberellic acid was first isolated from Gibberella fujikuroi
• The ‘bakanae’ (foolish seedling) disease of rice seedlings,
was caused by a fungal pathogen Gibberella fujikuroi
reported by E. Kurosawa
There are more than 100 gibberellins reported from widely different organisms
such as fungi and higher plants

11. • Chloroplast development in leaves
• Mobilisation of nutrients
• Shoot formation(both lateral & adventitious)
• Tea plantation
• Apical dominance - REVERSAL
• Tissue culture(Both auxin & cytokinin are used in
tissue culture)
High auxin  rooting & High cytokinin  shooting
• Organogenesis(Eg – formation of leaves)
CYTOKININ
CM said to admin, Thanks

12. • F. Skoog and his co-workers observed that from the internodal
segments of tobacco stems the callus (a mass of undifferentiated
cells) proliferated only if, in addition to auxins the nutrients
medium was supplemented with one of the following: extracts of
vascular tissues, yeast extract, coconut milk or DNA
• Miller later identified and crystallised the cytokinesis promoting
active substance that they termed kinetin
Cytokinin that is naturaly occur in plant is zeatin & isolated from
from corn-kernels and coconut milk
H.H. Cousins confirmed the release
of a volatile ethylene from ripened
oranges that hastened the ripening
of stored unripened bananas

13. • Antagonistic to GA
• Resistance to environmental stress
• Abscission
• Dormancy of bud & seed
• Stomatal closure
ABSCISIC ACID
Anti raped a BDS student
All growth inhibitors are antagonistic to gibberlic acid
Inhibitor-B, abscission II and dormin were other names for ABA

14. Growth promoting activity
• Triple response(Horizontal growth of
seedlings, Swelling of the axis and
Apical hook formation)
• Fruit ripening
• Respiratory climactic
• Breaks seed(peanut seeds) and bud
dormancy(sprouting of potato
tubers)
• Promotes rapid internode/petiole
elongation in deep water rice plants
• Root growth and root hair formation
• Initiate flowering and synchronise
fruit-set in pineapples
• Induces flowering in mango
Growth inhibiting activity
• Senescence and abscission
of leaves and flowers
ETHYLENE
Source of ethylene is ethephon.
Ethephon is readily absorbed
and transported within the plant
and releases ethylene slowly
Ethephon hastens fruit ripening
in tomatoes and apples and
accelerates abscission in flowers
and fruits (thinning of cotton,
cherry, walnut)
It promotes female flowers in
cucumbers thereby increasing
the yield

15. • Auxin was 1st identified by F W Went, from coleoptiles
of oat seedling
• It was first isolated from human urine
• In is developing from indole ring od tryptophan
• Natural auxins - Indole acetic acid(IAA)
Indole buteric acid(IBA)
• Synthetic auxins - Naphthalene acetic acid(NAA)
2, 4-dichlorophenoxyacetic(2,4D)
Avinna curvature test on Canary grass
explained by Charles Darwin & Francis
Darwin shows that auxin is
responsible for phototropism

16. PHOTOPERIODISM
Phytochrome is the protein responsible for
photoperiodism
Based on plant response towards photoperiod, they
are of three types
1. Long day plants(Short night plants)
2. Short day plants(Long night plants)
3. Day-neutral plants
The site of perception of light/dark duration are the leaves
There is a hypothetical hormonal substance(s) that is responsible
for flowering. This hormonal substance migrates from leaves to
shoot apices for inducing flowering

17. VERNALISATION
• Some important food plants, wheat, barley, rye
have two kinds of varieties: winter and spring
varieties
• The ‘spring’ variety are normally planted in the
spring and come to flower and produce grain
before the end of the growing season
• Winter varieties, however, if planted in spring
would normally fail to flower or produce mature
grain within a span of a flowering season

18. SEED DORMANCY
Physical reason: Impermeable and hard seed coat
Chemical reason: Abscissic acids, phenolic acids, para-ascorbic acid
Biological reason: Immature embryos
How to overcome seed dormancy ?
Mechanical method: Using knives, sandpaper or vigorous shaking
Chemical methods: Chemicals like gibberellic acid and nitrates
Physical method: Changing light and temperature