effects of air pollutants Effects of air pollutants on plants air polluion and control

1. Effects of air pollutants on
Plants
Ravi Kumar GARRE

2. Contents covered
• Introduction
• Structure of leaf
• Forms of damage to leaves
• Effects of various pollutants

3. Introduction
• Air pollution has long been known to have
adverse effects on plants.
• At first, the sulphur dioxide and fluorine have
more and dangerous effects on plants.
• Now a days, various pesticides and industries
causing dangerous injuries to plants.
Sometimes, vegetation over 150km away from
the source of pollutant has been found to be
affected.

4. Structure of a leaf

5. Structure of leaf

6. Structure of leaf
Epidermis:
• Forms a boundary between the plant and the
external environment.
• It protects against water loss, regulates gas
exchange, collects metabolic compounds and
especially in roots absorbs water and mineral
nutrients.

7. Structure of leaf
Palisade:
• Palisade cells contains number of chloropalsts in
plant leaves.
• These are well positioned to absorb light energy
required for photosynthesis.
• It converts light into chemical/ organic energy.
Parenchyma:
• Parenchyma cells are alive at maturity.
• They function in storage, photosynthesis.

8. Structure of leaf
Stomata:
• Stomata are the entrances in the leaf at top and
bottom.
• They can be closed/ opened by leaf itself.
• Through stomata air can enter in or exit from leaf.
• Most plants close their stomata at night.
• Therefore plants are much more resistant during
night.

9. Forms of damage to leaves
• Necrosis – killing/ collapse of tissue
• Chlorosis – loss/ reduction of chlorophyll
• Abscission – dropping of leaves
• Epinasty – downward curvature of leaf due to
higher rate of growth on the upper surface.

10. Phytotoxicants
• Phytotoxicant is the name given to plant
damaging substances.
• Various phytotoxicants are – sulphur dioxide,
fluorine, hydrogen fluoride, ozone, chlorine,
hydrogen chloride, oxides of nitrogen,
ammonia, ethylene, PAN.

11. Effects of air pollutants on plants
Sulphur dioxide:
• It is phytotoxicant above 0.2ppm.
• It causes leaching leaves, necrosis.
• If less than 0.4ppm, it get absorbed by leaf
and get oxidised.
• It affects photosynthesis and reacts with
moisture in tree.

12. Effects of air pollutants on plants
Fluorine
• Fluorine is phytotoxicant above 0.3µg/m3.
• It causes damages to fruits and flowers.
• Lowers the value of crop.
• It causes necrosis at leaf tip.

13. Effects of air pollutants on plants
Hydrogen fluoride:
• It causes similar effects with sulphur dioxide. But
it is 10 times effective than sulphur dioxide.
• It causes leaching leaves, necrosis.
• It get absorbed by leaf and get oxidised.
• It affects photosynthesis and reacts with moisture
in tree.
• However the recovery of effects of hydrogen
fluoride from plants is much slower than that of
sulphur dioxide.

14. Effects of air pollutants on plants
Ozone:
• Above 0.2ppm, it is a phytotoxicant.
• It causes lesions on upper surface of leaf,
premature aging, suppressed growth, collapse
of leaf.
• It also causes necrosis and bleaching.

15. Effects of air pollutants on plants
Chlorine:
• Damage to vegetation caused by chlorine is very
rare.
• It causes marginal lesions and inter-venial lesions
Hydrogen chloride:
• It causes necrosis and chlorotic margin.
• At higher concentrations lesions also formed.
(above 10ppm)

16. Effects of air pollutants on plants
Oxides of Nitrogen:
• Nitric acid is harmful to plants.
• Nitric acid and oxides of nitrogen absorbed by
plants causes lesions on leaves.
• Causes suppressed growth of leaf, bleaching of
leaf.
• Also causes brown margins and brownish black
spots on the leaves.
• If its concentration above 25ppm, causes these
effects.

17. Effects of air pollutants on plants
Ammonia:
• It causes necrosis and chlorotic margin.
• At higher concentrations lesions also formed.
Ethylene:
• Ethylene causes injury to leaves of sensitive
plants.
• The effects are epinasty, curling, chlorosis, leaf
abscission and growth retardation.

18. Effects of air pollutants on plants
PAN:
• Bronzing of lower leaf surface(Upper leaf
surface is normal).
• Causes suppressed growth.
• Especially attacks young leaves.

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