Osmoregulation in Plants

1. Integrated Science
M2*U5*L6(b)
BEGINBEGIN

2. CREDITS OBJECTIVES
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Objectives
You should be able to:
1.define osmoregulation.
2.describe the four types of plants based on their adaptations for
osmoregulation.
3.state the importance to plants of conserving/storing water.
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NOTE: For the activities in this slide show, you will be asked to type your
responses in boxes.
To do so, you must be in Slide Show View. You can insert and delete text in
the box in Slide Show View.

3. CREDITS OBJECTIVES
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Introduction
The protoplasm of living organisms has a high percentage of water,
so without water, living organisms would die.
Plants living in water, or those in hot, arid conditions where water is
not readily available all the time, or in which there is a high
concentration of solutes such as occurs in/near sea water, must
adapt their structure and/or their various functions – or both - to
ensure the conservation of needed water and prevent the upset of
the osmotic balance of cell contents.
Without the right osmotic balance – the plant dies!Without the right osmotic balance – the plant dies!
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4. CREDITS OBJECTIVES
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Surviving the salt
These Mangroves grow in wet,
muddy soil at the sea -water's
edge. If you look at the leaves,
salt crystals are excreted on to
their surfaces, and if you taste
the sap – it’s very salty!
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How can they live with so much salt?

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Surviving the salt
Most trees cannot
survive in water that has
too much salt in it, but
mangrove trees have a
unique adaptation for
dealing with the sea's
salinity.
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Some mangroves are almost covered by salty sea water!
Read the ‘One ingenious plant’ to the end of ‘Roots that Multitask’ at:
http://www.amnh.org/explore/science-bulletins/bio/documentaries/mangroves-the-roots-o
http://images.all-free-download.com/images/graphiclarge/grass_trees_hd_picture_165975.jpg

6. CREDITS OBJECTIVES
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Surviving the salt
Now, read the first four paragraphs at >
http://www.naturia.per.sg/buloh/plants/mangrove_trees.htm
When they’re submerged in sea water, warty growths on mangrove
roots filter out most of the salt as they take water in through their
roots.
Some mangroves concentrate extra salt in old leaves (which turn
yellow and die), and some are able to get rid of the salt by secreting
it through the pores of special glands.
Source: http://wiki.answers.com/Q/Why_mangroves_live_in_salt_water?
#slide=5
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7. CREDITS OBJECTIVES
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Surviving drought
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How do they survive?
In contrast to mangroves,
plants, such as these
cacti and Acacia that
live in places like along the
Palisadoes strip or in the
Hellshire area, grow in
limited, dry, sandy
soil, with little
rainfall, a very high
temperature and a
hot, dry wind.
There is little soil moisture.

8. CREDITS OBJECTIVES
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Some water-conservation methods
Look at the Cactus stem and those leaves.
Do they help you to answer that question?
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Succulent leaves of Sesuvium &
Aloe
Succulent plant stem
(Cactus)
Succulent plant stem
(Cactus)
How do they survive?

9. CREDITS OBJECTIVES
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Osmoregulatory adaptations
The plants shown on the previous slides have adaptations that
ensure osmoregulation.
Osmoregulation is the active regulation of the osmotic pressure
of an organism’’s fluids to maintain the homeostasis (or constant
unchanging balance) of the organism’s water content; that is, it
keeps the organism's fluids from becoming too diluted or too
concentrated.
Think and recall what you learned about osmosis in term 1.
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Source: http://en.wikipedia.org/wiki/Osmoregulation

10. CREDITS OBJECTIVES
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Osmoregulatory adaptations
Plants such as mangroves
develop structural and
physiological
adaptations to regulate
the osmotic balance of
their cell contents – i.e.
To carry out osmoregulation.
The cacti and other plants
living along the hot, dry
scrubland of the Palisadoes
strip also develop special
adaptive features for
osmoregulation.
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11. CREDITS OBJECTIVES
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Osmoregulatory adaptations – Types of plants
Depending on their habitat, plants can be grouped into four different
types according to the osmoregulatory adaptations that they show
either in their structure, functions, or both.
Groups are as follows:
1. Halophytes
2. Hydrophytes
3. Xerophytes
4. Mesophytes
Read the section on ‘Osmoregulation in Plants’ at >
http://en.wikipedia.org/wiki/Osmoregulation
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12. CREDITS OBJECTIVES
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Activity
1. When you open this video, click pause each time text appears
so that you can read it properly >
http://www.youtube.com/watch?v=lBzHYzXjdTo
Play it twice if necessary!
2. In which group would you place the following plants?
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a. Mangrove = halophyte
b. Cactus = xerophyte
c. Ackee tree = mesophyte
d. Water lily = hydrophyte
Groups:
1. Halophytes
2. Hydrophytes
3. Xerophytes
4. Mesophytes
CHECKCHECK

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Activity: Hydrophytes
3. What adaptations do these water lilies show for living in water?
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The leaves float on the water surface and
numerous stomata are present on the upper
surface of the leaves facing the atmosphere to
promote loss of water. The surface area of these
leaves is very large to enable excessive water
loss by transpiration.
CHECKCHECK

14. CREDITS OBJECTIVES
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Feedback to Activity
FEEDBACK.
2. (a) mangrove = halophyte
(b) Catus = xerophyte
(c ) an ackee tree = mesophyte
(d) water lily = hydrophyte
3. The leaves float on the water surface and numerous stomata are
present on the upper surface of the leaves facing the atmosphere to
promote loss of water. The surface area of these leaves is very large
to enable excessive water loss by transpiration
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15. CREDITS OBJECTIVES
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Why is osmoregulation important to plants?
the habitat is dry, hot and desert-like.
sandy/rocky soil does not hold much water.
rainfall is scarce or only at certain times.
adequate water is not available for photosynthesis and
hydration of the cell contents.
habitat is completely aquatic.
salinity of the habitat is high.
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1. Enables the plant to grow, develop, carry on respiration,
photosynthesis and survive, even if:
2. It regulates and balances the uptake and loss of water and
solutes so maintains homeostasis.

16. CREDITS OBJECTIVES
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Credits
 http://www.mangrove.at/images/mangrove/forests/overwashed/overwashed
%20mangrove%20forest.jpg
 http://images.all-free-
download.com/images/graphiclarge/grass_trees_hd_picture_165975.jpg
 http://www.palmislandestates.org/images/environmental/mangroves.jpg
 http://scienceray.com/biology/botany/the-desert-saguaro/
 http://www.cbd.int/doc/world/jm/jm-nbsap-01-p4-en.pdf
 http://keetsa.com/blog/wp-content/uploads/2009/06/aloe-vera-plant.jpg
 http://commons.wikimedia.org/wiki/File:Avicennia_germinans-salt_excretion.jpg
 http://wiki.answers.com/Q/Why_mangroves_live_in_salt_water?#slide=5
 http://www.shutterstock.com/pic-141931372/stock-photo-lotus-flower-in-thailand.html?
src=pp-photo-61336477-vmC5123JqUfb8rxqG8USKw-2
 http://www.shutterstock.com/pic-172736525/stock-photo-victoria-regia-the-largest-
water-lily-in-the-world.html?src=vmC5123JqUfb8rxqG8USKw-5-35
 Sesuvium sp.- http://dspace.mona.uwi.edu
 Slide 14: Aloe vera - http://waterconservationwise.com.au/water-efficient-plants
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