Algae

Botany phycology

1. NAME: NADIA IMDAD
SUBMITTED TO: M,AM RABIA LIAQAT
DEPARTMENT: BOTANY
COURSE TITLE: PLANT PHYSIOLOGY
COURSE CODE: BOT-306
U O G

2. TOPIC
ROLE OF ALGAE IN PLANTS

3. ALGAE

4. Algae - What are they?
•Primitive plants
•No true roots, only attachment
structures (Holdfasts)
•Produce spores (not seeds)–
motile or non-motile
•Most have sexual and asexual
reproduction
•Non-vascular, do not possess
an internal transport system.

5. Characteristics Of Algae
•Vary in size from
nanoplankton (< 2 µm
cyanobacteria ) to Giant kelps
(> 70 m long). Possess a cell
wall.
•Contain pigments
•chlorophylls a, and many
often have another
chlorophyll, like b, c, or d
and accessory red, blue
and brown photosynthetic
pigments

6. Classification Of Algae
•Cyanophyta: Blue-green or Cyanobacteria.
Prokaryotic,Marine,and terrestrial.
•Pyrrophyta, Chrysophyta, Euglenophyta: Marine
and phytoplankton – Photosynthetic Protists.
KINGDOM PLANTAE:
•Rhodophyta: Red algae. Mostly marine.
•Phaeophyta: Brown algae. Mostly marine.
•Chlorophyta: Green algae. Marine, and
terrestrial.

7. The role of these pigments is to absorb
light
- In water the problem is that red and violet wavelengths do not
penetrate the vertical column very well. So Chlorophylls do not
work well at greater depths. Algae that inhabit greater depths do so
with the help of accessory pigments, these algae take on a variety of
colours.

8. -Chlorophyta – Contain
Chlorophyll a + b. So green
wavelengths reflect. They store
their products of photosynthesis
as starch.
- Phaeophyta – Contain
Chlorophylls a + c as well as an
accessory pigment Fucoxanthin.
So yellow and brown
wavelengths reflect. Store food
as starch and as oil.
Rhodophyta - Contain
Chlorophyll a + (d) as well as
accessory pigment Phycobillins.
These phycobillins are
specialized for absorbing blue
light, which allows them to
inhabit the deepest depths.

9. Morphology Of Algae
1. Unicellular algae
2. Colonies
3. Filaments
4. Multicellular

10. Unicellular algae
•‘Microalgae’ - some may form colonies

11. Colonies
e.g. Chlorophyta: Volvox

- 500-5000 cells per colony.
- Colonies spherical up to 1.5 mm diameter.
- Individual cells surrounded by a mucilaginous sphere
- marine and freshwater

12. Filamentous algae
•Unbranched filaments
•Branched filaments
•Different branches can have different
morphologies:

13. MULTICELLULAR - Macroscopic

14. Where do Algae live?
Marine habitats:
•seaweeds, phytoplankton
Freshwater habitats:
•streams, rivers, lakes
and ponds
Terrestrial habitats:
•stone walls, tree bark,
leaves, in lichens, on
snow

15. Marine Biomes

16. Freshwater habitats

17. Terrestrial habitats

18. How do algae function?
Photoautotrophs: 6C0
2
+ 6H
2
0 
C
6
H
12
0
6
+ O
2

•use carbon, light, and water
•produce chemical energy
(carbohydrates) and produce O
2 as
a by-product.
•Basic storage products:
carbohydrates as starch or
converted to fats as oil
•Require nutrients: N, P and
minerals.

19. Why are ALGAE important?
Ecological importance of algae
a) Production of Oxygen as ‘by-
product’ of photosynthesis:
•All aerobic heterotrophic
organisms require O2,
•e.g. fungi and animals need O2, to
run cellular respiration to stay alive
b) Production of biomass:
•autotrophic organisms
- represent the base of the food
chain/web,
particularly in aquatic
environments.

20. Why are algae important?
•Primary producers, basis of food webs,
“FORESTS/GRASSES OF THE SEA”
•Pioneer Species: on rocky shores, mudflats,
hot springs, lichen communities, 'snow algae'
•O2 production and carbon fixation in aquatic
habitats.
•Rare autotrophic organisms in extreme
habitats.

21. Examples of ecological importance
•Red tides, other algal blooms
•Hot springs
•Kelp forests
•Rocky shore ecology
•Aquaculture

22. Cyanobacterial bloom

23. Extreme halophytes

24. Uses of Seaweeds
•Present
•Food
•Hydrocolloids and some
chemical substances
•Fertilizers
•Potential
•Source of
energy/compost by
digestion
•Waste-water treatment

25. Algae as human food
•Annual value is about US$6 billion
•Main market and production area is Asia
•“Mariculture” has become very important
•Main high-value species are ‘Nori’, ‘Kombu’ and
‘Wakame’ (Porphyra, Laminaria and Undaria)
•Mainly used as a subsidiary food: adding relish, taste
and 'feel' to food
•European and North American market presently very
small but has potential