plant growth and development

2. Growth: in living organisms may be
defined as an irreversible increase in
the number and size of a cell, organ
or whole organism ,related to change
in size & mass .
Development:refering to the sum of
all changes that an organism
undergo through its life cycle from
seed germination ,and through
growth,maturation ,flowering,and
senescence .

3. Growth
Growth is regarded as one of the most fundamental
and conspicuous characteristics of a living being.
Generally, growth is accompanied by metabolic
processes (both anabolic and catabolic), that occur
at the expense of energy. Therefore, for example,
expansion of a leaf is growth.

4. Types of Growth-
Classified by Developmental Stages
Primary growth:
Apical meristems extend
roots and shoots by giving
rise to the primary plant
body
Secondary growth:
Lateral meristems add
girth by producing secondary
vascular tissue and
periderm.

6. MEASUREMENT OF GROWTH
It can be measured in terms of:
 Increase in length or growth – in case of
stem and root.
 Increase in area or volume – in case of leaves
and fruits.
 Increase in the number of cells – in algae,
yeast and bacteria.

7. Types of Growth & Development
 Vegetative Phase
– Carbohydrate Utilization
Reproductive Phase
– Accumulation or storage of
carbohydrates

8. Vegetative Phase
 • From seed germination through growth of the
 primary supportive structure
 • Three important processes:
 – Cell division
 – Cell enlargement
 – Cell differentiation (initial stages)

9. Reproductive Growth Phase
 Maturation of tissues manufactured during
 vegetative phase
 Production of growth regulators
 Development of flower buds, flowers, fruit
 and seed, or the development of storage
 organs
 Relatively little cell division occurs
 Most of the carbohydrates are accumulated
 in the fruit, seed or storage organs

10. Phases of Growth
 Meristematic: both at the root apex and the shoot apex,
represent the meristematic phase of growth.
Meristematic Cells (Stem Cells)
Primary
Shoot Apical Meristem (SAM)
Root Apical Meristem (RAM)
Secondary
Axillary Buds
Vascular Cambium
Cork Cambium
Pericycle (root)

11.  Elongation:The size of individual cell increases after cell division
due to increase in the volume of its protoplasm.
 Adjacent to Meristems
 Internode growth - Shoot
 Zone of Elongation – Root
 Turgor Pressure
 H2O Uptake
 Cell Wall Loosening
 new cell walls

12.  Maturation(differenciation) :In this stage, structure of
the cells changes to perform specific functions. And
similar type of cells having same functions form a
group, which is known as tissue.
 Secondary cell walls
 Xylem - Vascular tissue
 Fibers
 Epidermal cells
 root hairs
 leaf hairs
 guard cells
 Leaves, Flowers
 Fruit, Tubers, Bulbs, etc

13. Growth Rates
The increased growth per unit time is termed as growth rate.
Thus, rate of growth can be expressed mathematically. An
organism, or a part of the organism can produce more cells in
a variety of ways.
Two types of growth rates :
 In arithmetic growth, following mitotic cell division, only one
daughter cell continues to divide while the other differentiates
and matures. The simplest expression of arithmetic growth is
exemplified by a root elongating at a constant rate.
 In geometrical growth ,both the progency cells following
mitotic cell divide and continue to do so .
 During the the development of an embryo ,both types of
growth rates are involved .this transforms asingle cell zygote
into a multicellular organisms .

15. GROWTH CURVE
The rate of growth of a plant or plant part is not always the same
during its life span.
Sometimes it is slow and at other times rapid. If we plot the
increase in cell number (growth rate) against time, a typical S-
shape curve is obtained. This is called growth curve or
sigmoid curve.
This curve has three phases of growth.
(i) Lag Phase – This is the initial phase of growth when the rate
of growth is
very slow.
(ii) Log Phase – It shows rapid growth and is maximum for the
entire life span.
(iii) Stationary Phase – Here the rate of growth starts
decreasing and finally it
stops.

16. GROWTH CURVE

17. Growth Requirements
 Nutrients
 Water
 Temperature (Heat)
 Light
 Growth Substances (Hormones)

18. Types of Growth:
Growth is of two types
Indefinite or unlimited growth exhibited by
root, stem and their branches,
 Definite or limited growth exhibited by
leaves, flowers, fruits, etc.

19. Development is the sum of two processes: growth and
differentiation. To begin with, it is essential and sufficient
to know that the development of a mature plant from a
zygote (fertilised egg) follow a precise and highly ordered
succession of events. During this process a complex body
organisation is formed that produces roots, leaves,
branches, flowers, fruits, and seeds, and eventually they
die.

20. Development is associated with morphogenesis and
differentiation. Morphogenesis :is the process of
development of shape and structure of an organism.
When a cell loses the capacity to divide, it leads to
differentiation. Differentiation results in development
of structures that is commensurate with the function
the cells finally has to perform. General principles for
differentiation for cell, tissues and organs are similar. A
differentiated cell may dedifferentiate and then
redifferentiate. Since differentiation in plants is open,
the development could also be flexible, i.e., the
development is the sum of growth and differentiation.

22. Plant exhibit plasticity in development.ants follow
different pathways in response to environment or
phases of life to form different kinds of structures.
This ability is called plasticity.

23. Control of growth and development
Thus, growth, differentiation and development are very closely
related events in the life of a plant. Broadly, development is
considered as thesum of growth and differentiation.
Development in plants (i.e., both growth and differentiation)
is under the control of:
1- Inter cellular controls :Involves in changes in gene
expression that infleunces cellular activeties through altering
the kind of protiens in the cell.
2-Intra cellular controls: focus on hormones(phytohormones)
and their role the activities of groups of cells .
3-Extra cellular controls :they originate outside the organism
and information about the
Any change in the environmental conditions that may adversely
affect the growth or development in plants is called biological
stress. This stress occurs mainly due to temperature, water,
salt, shade, light, and various pollutants.

24. Acomparative of plant growth regulatorson plant development
Auxin GA cytokini
ne
ABA Ethylen
e
Root
developm
ent
+ + + _ +
Extension
growth
+ + + + +
juvenility + + _ _ _
Flowering + + + + +
Fruiting
developm
ent
+ + + + +
senescenc
e
+ + + _ +
dormancy _ + + + +

25. Patterns of Early Growth
and Development
Seed germination
Dependent on
Temperature
Moisture
Oxygen
Daylight hours
Imbibition
Coat ruptures
Seed swells from H2O
update

26. Growth vs Development
Growth
Quantitative
Number, size, and
volume increase
Development
Qualitative
Emergence of
specialized body
parts

27. MEASUREMENT OF GROWTH
It can be measured in terms of:
 Increase in length or growth – in case of
stem and root.
 Increase in area or volume – in case of leaves
and fruits.
 Increase in the number of cells – in algae,
yeast and bacteria.

28. Types of Growth & Development
 Vegetative Phase
– Carbohydrate Utilization
Reproductive Phase
– Accumulation or storage of
carbohydrates

29. There are 6 plant processes that effect
growth which are….
Photosynthesis
Respiration
Absorption
Transpiration
Translocation
Reproduction

30. Growth Processes
• Photosynthesis
– Creating carbohydrates (stored energy) from CO2 +
water + sunlight in the presence of chlorophyll.
• Respiration
– An energy releasing reaction; chemical energy
originating through photosynthesis is used for growth
and development.
• Net Photosynthesis
– Total Photosynthesis – Total Respiration
– Net Photosynthesis = Biological Yield
• Increasing Total Photosynthesis or Decreasing
Respiration
will Increase Biological Yield

31. As a plant germinates and matures, it
undergoes the processes of growth and
development. Growth arises from the
addition of new cells and the increase
in their size. Development is the result
of cells differentiating into a diversity of
tissues that make up organs such as
roots, shoots, leaves, and flowers. Each
of these organs has specialized
functions coordinated to enable the
individual plant to complete its cycle in
the spiral of life.

32. As the plant grows, the stem elongates
at the internodes, which is the space
between the nodes (where the leaves
attach).
This allows the plant to grow taller and
spread out the leaves and flowers so
they are in the best position to do their
jobs.
Stems also allow food, water, and
minerals to move throughout the
plant.

33. the growth and development
of plants is not just limited to an embryonic
or juvenile period, but occurs throughout
the life of the plant.
– At any given instance, a typical plant
consists
of embryonic organs, developing organs,
and mature organs.

34. Plant development
 seed structure and development
 Seed germination
 Shoot development
 Root development
 Flower evocation and development
 Flower and fruit development

35. Germination and seedling development in bean

36.  The shoot apical meristem repetitively forms
 units known as phytomeres. Each phytomere consists of
 one or more leaves, the node at which the leaves are
 attached, the internode immediately below the leaves, and
 one or more buds in the axils of the leaves.

37. Root development

38.  Dormancy is the state where a plant stops growing.
 Breaking dormancy involves exposure to certain
temperatures and hormones.
 Plants have biological clocks that make daily and seasonal
adjustments in patterns of growth, development and
reproduction

39. Senescence:A program in which the
function of organ or whole plant
naturally declines to death. This is an
essential phase of the growth and
development in plant .Senescence is
an active developmental process that
is controlled by the plant’s genetic
program and initiated by specific
environmental or developmental
cues. 。