Biology Activity 1.2 (Koh Yi Wen,Leong Jia Jie,Ng Jun Yuan,Low Ching Yee and Lim Shu Ye)

BIOLOGY PRESENTATION:
1.2 : Meristematic Tissues & Growth

Activity 1.2

Group member

1ST 3RD 5TH
2ND 4TH

Lim Shu Ye Ng Jun Yuan Koh Yi Wen
Low Ching Yee
Leong Jia Jie

Aim:To gather information on the necessity of primary and secondary growth

INTRODUCTION

Meristematic tissue Primary Growth Secondary Growth

Apical meristems Lateral Meristem - begins after germination - Increase in
and it takes place in all circumference or
- Found in - Increase of plants to elongate their diameter of plant stem
stems & roots and root
tips of diameter of
- Apical meristem - Mainly occur in eudicots
roots and stem and - shoot tips, leaf and a small number of
primordia & shoot monocots
shoots root primordia
- root tips, root cap - Lateral meristem
- Contributes - Consist of - vascular cambium,
vascular between phloem &
to extension xylem
cambium - Cork cambium, under
of plant to epidermal layer
and cork
make it * does not happen in non-woody
cambium plants (herbaceous plant)
grow taller

Zone of D ivision
Cell E longation
D ifferentiation
Growth

01Necessity of primary growth

In terms of height , support and transportation

i ) HEIGHT

Allow maximum elongation of plant

-Increase in height come from apical
meristems (at shoot tips and root tips)

-At shoot tips, leaf primordia and shoot
primordia will grow to form new leaves

and shoots.

-enable the plants to absorb sunlight
for photosynthesis

ii）SUPPORT The growth of roots causing the
root to lengthen in the soil.
Primary xylem provides support to
herbaceous or young plants - It anchors the plant firmly to
the soil
- The internal hydrostatic pressure keep
them rigid and resistant to bending

iii）TRANSPORTATION

Primary xylem can transport water
and mineral salt

- From the soil via the roots
to the leaves (transpiration)

Primary phloem can transport products
of photosynthesis

- From the the leaves to
other parts of the plants
(translocation)

02

the need of secondary
growth to increase:

● support
● transportation

Heights (meters) Introduction : secondary growth ● Secondary growth is
important to woody
Unlimited Growth Curve of Perennial Plant plant as they grow
much taller than other
Time (years) plants. Thus, they need
more support in their
stems and roots

● Secondary growth
allow plants continue
living and growing for
many years. So, they
can produce flowers
and seeds season to
increase the chances
of propogation of
species.

The need of secondary growth (SUPPORT) Steps to develop strong
woody plants
Aspect Function
1. Secondary growth starts
Mechanical Support - Increasing diameter of their when vascular cambium
stems and roots give support divides mitotically
to the increasing weight of
aerial growth 2. Cells in cambium ring
divide inward to produce
- Cells of secondary xylem are new xylem, divide outward
thickened with lignin to produce new phloem

Protection - Produces stronger and 3. Xylem is compressed to
thicker bark to prevent form stronger wood layer
excessive water loss,
physical injuries and pathgen 4. Thus, circumference of the
infections stem increases, the
epidermis of stem stretch
and crack

Do You Know?
Aerial Growth: growth happens toward the air

The need of secondary growth
(Transportation)

● Produces more xylem and phloem tissues
to accomodate the increase in demand
for water, mineral and organic nutrients

● Produces xylem and phloem tissues
continuously to replace old and
damaged xylem and phloem tissues

03

IMPORTANCES OF PLANTS UNDERGOING SECONDARY
GROWTH ECONOMICALLY

There many types of plants that undergo
secondary growth and provide several sources
such as timber,resin,fruits and flowers.This products

can be processed to sell and increase the
income of seller as well as boost economic

growth.

(A)Timber/Woods.

(i)Wooden products

-After conducting secondary growth,the woods of plants will become
hard and strong.It is because during secondary growth,the primary
xylem tissues are compressed and the wall of xylem is thickened by
lignin.And thus,the strong wood layer is formed.Besides,the cork
cambium also divides actively to form cork cells on outer side and
cortex in inner side.

Xylem tissues which compressed Cork cambium which divides actively
and thickened by lignin through mitosis and produce cork
cells,.cortex

-Due to its strong and thick structure,they can been produced into
several wooden products such as furniture,houseboats,fences and also
doors which have high quality

door

houseboats

Furniture

fences

(ii)Decorative items

-For woods which have beautiful and obvious annual ring
can been processed into decorative items.
-Cambium activities is influenced by season.
-Temperate plants undergo secondary growth at
different rate in each season.
-Growth of plant suitable in spring so secondary xylem
formed is bigger and the wall is thinner resulting brighter
colour ring as less colour concentrated.
-Growth of plant unsuitable in summer,causing the
secondary xylem formed is smaller and the wall is thicker
resulting darker colour ring as more colour concentrated.
-The continuous layer of brighter and darker ring formed
annual ring.We can count the annual ring to know the
age of a plant.

-The beauty of annual ring on the tree make the wood
suitable to make as decorative items.

plates

clock Decorative cabinet.

(B)Resin and oil. Resin on tree.

-Wood of some plants not only can make
wooden product and decorative items,they can
also produce resin and oil.
-Resin is known as a type of fluid which function
in trees by rapidly sealing over wounds to
invade insects and fungal disease agents move
into tree.The organisms that try to enter tree
via the wound can be flushed out and
overcome by resin’s toxicity.Resin can also
lower the amount of water lost.
-Resin usually stored in ducts or blisters,when
they oozes out through bark,it will harden when
exposed to air through oxidation process.

-So,this resin Perfume
and oil can be
processed into
varnish,adhesive
substances,
perfume and
also medicine.

(C)Fruits. Examples of tropical fruits

-Through undergoing secondary
growth,several plants able to
produce out fruits.
-For example,some examples of
tropical fruits such as
banana,durian,pineapple,papaya
and avocado can been exported
out to Europe as europe's
weather not suitable for tropical
fruits to grow.
-and then we can gain income
through selling the tropical fruits.

(D)Flowers.

-Through secondary
growth,some plants
able to produce
flower
-so,the flower can
made as decorative
products and also gift
to give others people

Conclusion

What we learned via this activity?

Conclusion

Just as human who undergoing baby,
child, puberty, teenager stages to be
an adult, plants will also undergo
primary and secondary growth to be
mature.

Conclusion

All of the growth processes are efforts to Just like we have family, plants have too. We
carry out reproduction and offspring should respect and love the lives. We
continuation of their variety. shouldn’t take the beauty of nature mother
for granted. Gratitude should be expressed
via action to show the honour of lives.

Conclusion

From the study of plant growth, we will
be surprised by amazement of lives.
They undergo cell division, elongation,
differentiation, evolution and even
mutation among the history, just to
demonstrate themselves and the variety
of the world.

Colour Shape Dimension

Life is fantastic

「Life has no the feature that it ‘should be’ 」

- Koh Yi Wen

Option 1 Option 2

Or Tree……

t

You can do more than you think

Reference

Book reference :

1. Biology Form 5 textbook
2. Spotlight A+ Biology Form 4 & 5

Video reference :

1. https://www.youtube.com/watch?v=jtuX7H05tmQ

Reference

Internet reference :

1. https://online.fliphtml5.com/ffzny/qtne/#p=25
2. https://news.sina.cn/2018-02-05/detail-ifyreuzn3425771.d.html
3. https://www.52zzl.com/zhiwu/31646.html
4. https://www.photophoto.cn/tupian/zhiwushengchangjieduan-

32146390.html
5. https://www.tga.gov.au/blogs/tga-topics/too-much-good-thing-health-

risks-human-growth-hormone
6. https://qsstudy.com/formation-annual-ring/
7. https://www.thoughtco.com/what-are-tree-resins-1343409
8. https://study.com/academy/lesson/secondary-growth-in-plants-lesson-

quiz.html

The End

After this activity, my teammates and I fully comprehend the
precious of lives. Hope you guys too !