PAPER OF PLANT PHYSIOLOGY
PLANTH GROWTH AND DEVELOPMENT
GROUP 6
1.
ELLA EKA PUTRI
2.
RADILA
WIDAYATI
BIOLOGY MAJOR
MATHEMATIC AND SCIENCE FACULTY
PADANG STATE UNIVERSITY
2014
PLANTH GROWTH AND DEVELOPMENT
A. Growth
and Development Concept
Growth is a process that is irreversible increase
in volume (irreversible), and is due to the increase in the number of cells and enlargement of
each cell. In
normal growth process
is accompanied by a change in shape. Growth
can be measured and expressed quantitatively. The development is the process to
adulthood. The process of development runs parallel to the growth.
In contrast to the growth, development is a process that can not be measured. In other words, the development of a qualitative nature, can
not be expressed numerically.
In plants, the growth started from seed germination process.
Germination can occur
when the water content in the seeds of higher due
to the influx of water into the seed
through imbibition process. If the process
is optimal imbibition, germination begins. The structure of the first to appear, which tore the lining of seeds
is radicle who
are candidates for primary roots.
Radicle is part
of the hypocotyl. At the upper end there
epikotil (candidate stem). Based on the
location of kotiledonnya, there
are two types of germination is epigeal
type, and the
type hipogeal.
Hipogeal
germination
Epigeal germination
In general, developments in plant
growth and begins
to stage the
embryo is fertilized by the male female
sex cells. Cleavage of the zygote produces meristem
tissue will continue to divide
and differentiate. Differentiation is the
change of state of a number of cells, forming
organs have different
structures and functions. Seeds that have germinated will soon be followed by
primary growth because of the shoot and root tip meristematic there
are network (always
splitting). Elongation of the root tip and the
tip of the rod is called the
primary growth. In dicotyledonous plants are
cambium tissue which
is a secondary meristem will cause secondary
growth (enlarged). Cambium will cleave
to the outward form
of bark (phloem), and splitting the
direction in shaping wood (xylem). In monocots
no cambium so
that only primary growth alone. Primary
and secondary growth continues
during the plant
life. There are two
kinds of growth, namely:
1. Primary Growth
Occur as a result of cell division-cell primary meristem tissue. Takes place in the embryo, part of the ends of the plants such as roots and stems.
Occur as a result of cell division-cell primary meristem tissue. Takes place in the embryo, part of the ends of the plants such as roots and stems.
The embryo has three important
parts:
a. embryonic stem that is a candidate stems and leaves
b. embryonic roots are roots candidate
c. cotyledons ie food reserves
Plant growth can be measured with an instrument called auksanometer.
a. embryonic stem that is a candidate stems and leaves
b. embryonic roots are roots candidate
c. cotyledons ie food reserves
Plant growth can be measured with an instrument called auksanometer.
Regional growth in roots and stems divided
based activities into 3 regions
a. Area division cells in this region actively dividing (meristematic)
b. Elongation area. Is behind the cleavage area.
c. Regional differentiation. Rearmost part of the growth area. Cells undergo differentiation to form the actual roots and young leaves and lateral buds will be a branch.
a. Area division cells in this region actively dividing (meristematic)
b. Elongation area. Is behind the cleavage area.
c. Regional differentiation. Rearmost part of the growth area. Cells undergo differentiation to form the actual roots and young leaves and lateral buds will be a branch.
2. Secondary Growth
Is the activity
of the cells of the secondary meristem cambium and cork cambium. This growth is
found in dicotyledonous plants, gymnosperms and causes enlargement of the plant size (diameter). First cambium is only found in the vascular
bundles, called cambium Vasis or cambium intravasikuler. Its function is to
form the primary xylem and phloem. Next parenchyma
root / stem that lies between the vascular bundles, be called the cambium
intervasis cambium.
Cambium intravasis and intervasis circle year:
concentric shape. Cambium which is located next to the skin tissue that serves
as protector. Formed as a result of an imbalance between the xylem and phloem
permbentukan faster than the growth of the skin.
Into forming feloderm: living cells
Outward form felem: dead cells
Into forming feloderm: living cells
Outward form felem: dead cells
Factors affecting the growth and
development. Growth in plants is influenced by two factors, namely:
a. External factors
External factors are material or things that are outside of the plants that have an impact on the plants, either directly or indirectly. Belong to the external factors are light, temperature, water, mineral salts, climate, Earth's gravity, and others.
a. External factors
External factors are material or things that are outside of the plants that have an impact on the plants, either directly or indirectly. Belong to the external factors are light, temperature, water, mineral salts, climate, Earth's gravity, and others.
1. Nutrition
Plants need a certain amount of mineral elements. Elements are required in large quantities called macro elements, while the elements required in small amounts called micronutrients.
2. Light
Light is absolutely needed by all green plants to perform photosynthesis, but its influence on the growth of plants is to inhibit germination, because light can lead to the disintegration of auxin that can inhibit growth. It can be proved if we put two sprouts, which is one in a dark place and the other in the light. In the same period, the sprouts in a dark place to grow faster but not normal. Very rapid growth in the dark is called etiolation.
Plants need a certain amount of mineral elements. Elements are required in large quantities called macro elements, while the elements required in small amounts called micronutrients.
2. Light
Light is absolutely needed by all green plants to perform photosynthesis, but its influence on the growth of plants is to inhibit germination, because light can lead to the disintegration of auxin that can inhibit growth. It can be proved if we put two sprouts, which is one in a dark place and the other in the light. In the same period, the sprouts in a dark place to grow faster but not normal. Very rapid growth in the dark is called etiolation.
In plants, there is a pigment called phytochrome, which serves
to control the growth and development of chloroplasts, chlorophyll synthesis, formation
of plant hormones (eg gibberellins), and
setting the position of the leaves
to sunlight. Additionally, phytochrome also affect photoperiodism, namely the
influence of the length of the
lighting effect on the growth
and flower formation.
Based on the length and intensity of exposure, plants are grouped into three types, namely:
• Plant for days shorter (shortday plant): Flowering and fruiting when the irradiation period is shorter than the critical period. For example: strawberry, dahlias, daisies, and krisatinum.
• Plant for days long (longday plant): flowering and fruiting when the irradiation period is longer than the critical period. Examples: spinach lettuce, wheat, and potatoes.
• Plant neutral (dayneutral plant): Not influenced by the length of the period of irradiation. Example: roses, anyer, and sunflower.
3. Temperature
In general, the temperature will affect the action of the enzyme. When the temperature is too high, the enzyme will be broken, and if the temperature is too low enzyme becomes inactive.
4. The moisture or water content
Up to certain limits, the higher the water content, growth will accelerate. As more moisture is absorbed and evaporated fewer, will lead to the unfolding of the cells, so the cells more rapidly reaches its maximum size.
Based on the length and intensity of exposure, plants are grouped into three types, namely:
• Plant for days shorter (shortday plant): Flowering and fruiting when the irradiation period is shorter than the critical period. For example: strawberry, dahlias, daisies, and krisatinum.
• Plant for days long (longday plant): flowering and fruiting when the irradiation period is longer than the critical period. Examples: spinach lettuce, wheat, and potatoes.
• Plant neutral (dayneutral plant): Not influenced by the length of the period of irradiation. Example: roses, anyer, and sunflower.
3. Temperature
In general, the temperature will affect the action of the enzyme. When the temperature is too high, the enzyme will be broken, and if the temperature is too low enzyme becomes inactive.
4. The moisture or water content
Up to certain limits, the higher the water content, growth will accelerate. As more moisture is absorbed and evaporated fewer, will lead to the unfolding of the cells, so the cells more rapidly reaches its maximum size.
b. Internal factors
In addition to genetic factors, which include
factors in are
the hormones involved in plant growth. Hormones are substances produced
by plants, usually
in very small amounts in physiological functioning to control the direction and speed of growing
parts of the plant.
B.
Curve of Plant Growth
During
the life cycle, the plant will experience growth and development. Growth is the
addition of weight and volume or size of the plant due to the addition of
elements - a new structural element.
The
pattern of growth of an organ or whole plant form sigmoid growth, is the slow growth in the
initiation phase and then the next phase of growth will be faster
exponentially. Further growth will be slowed and eventually will be
approximately constant, so will makes
growth curve that resembles the letter "S". This is consistent with
the literature Tjitrosomo (1991) which states that plant growth was slow at
first, then gradually fade faster until a maximum is reached, eventually the
rate of growth decreases. If depicted in the graph in a given time will form a
sigmoid curve (form S).
On
plant growth slow at first, then gradually faster until a maximum is reached,
eventually the rate of growth decreases. According to Franklin P Gardner
(1991), is a sigmoid curve along a generation of growth pattern is typically
characterized by a function of growth. Sigmoid curve shape for all the plants
more or less fixed, but deviations may occur as a result of variations in the
environment. The final size, appearance and shape of the plant is determined by
the combined influence of heredity and environment (Tjitrosomo, 1999). In
addition, the age of the leaves can also affect the growth of plants as they
relate to the level of the rate of photosynthesis. The ability of leaves to
photosynthesize increased in the early development of the leaves, but then
began to fall, sometimes before the leaves are fully developed (fully
developed). The leaves began having senencene is yellow and lost its ability to
photosynthesize because reshuffle chlorophyll and loss of function of
chloroplasts (Lakitan, 1995).
Fig.
15.2 GROWTH CURVE- GROWTH PLOTTED AGAINST TIME
Plants
will experience growth and development as long as the phase of life. The
development of plants is very diverse, as well as developments in the leaves
that have a variety of shapes. Outward ongoing development through division,
both periklinal and anticlinal, at the end of the primordial (aspect / distal
end). Then when the leaves are about - about 1mm size, meristematic activity
began to occur in all parts of prolonged. In dicotyledonous plants leaves, most
of the cell division had long stopped before the leaves develop fully, often
when the leaves reach less than half the size of the end. In the logarithmic
phase, size (V) increases exponentially with time (t), which means slower growth
rate initially running, but then continues to rise, the linear phase, increase
the size of the constant breaks, usually at the maximum rate for some time.
Constant growth rate is shown by a constant slope on the top of a high curve
and the flat part of plant growth rate curve at the bottom, and the aging phase
is characterized by a fixed rate of growth or even decline when growth reached
a constant maturity (Dwidjoseputro. 1986) . Aging phase is
characterized by the growth rate decreases when the plant has reached maturity
and aging (Salisbury and Ross, 1992).
BIBLIOGRAPHY
Devlin, Robert M. 1993. Plant
Physiology. California : Wadsworth Publishing
Company.
Dwidjoseputro.
1986. Pengantar Fisiologi Tumbuhan. Jakarta : Gramedia.
Lakitan,
Benyamin. 1995. Dasar-Dasar Fisiologi
Tumbuhan. Jakarta : Gramedia.
Ritchie, Donald D. 1979. Biology
. New York : Addison Wesley Publishing Company.
Salisbury, F.B
dan C.W. Ross., 1992. Fisiologi Tumbuhan Jilid
Tiga Edisi Keempat.
Bandung : ITB.
Tjitrosomo,
G. 1999. Botani umum 2. Bandung : Angkasa.
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