How does Air Pollution Affect Plants – PPTs

Air Pollution and Plants – PPTs

Effects of Air Pollution on Plants

Here is the list of 5 air pollutants those effect plants.

Effect of Ozone on Plants

  • Ozone is the main pollutant in the oxidant smog complex. it is the triplet molecule of oxygen (O). Ozone in the stratosphere is beneficial for the humans as it protects from ultra violet (UV light), which is harmful for skin and plant burning. However, ground level ozone is not supportive for life on earth. it is dangerous either it is plant or animal.
  • Its effect on plants was first observed in the Los Angeles in 1944.
  • In the Los Angeles, USA, the white beans (sensitive) were observed for the first time as an indicator of damage.
  • Ozone injury occurs on the leaf upper surface those are highly exposed.
  • It causes bronzing or bleaching of the leaf tissues
  • The youngest leaves are resistant.
  • With expansion, they become susceptible
  • at middle and basal portions.

Bronzing: Do you know what is bronzing?

Leaf die at tips or margin

  • Sensitive species include; Cucumber, Grape, green bean, Lettuce, Onion
  • Resistant species include pear and apricot.

Effects of Sulfur Dioxide on Plants

a) Acute injury in plants is caused by absorption of high concentrations of sulfur dioxide in a relatively short time.

The symptoms appear as bifacial lesions that usually occur between the veins. The colour of the necrotic area can vary from a light tan or near white to orange-red or brown.

Expanded leaves usually are the most sensitive to acute sulfur dioxide injury, the very youngest and the oldest being somewhat more resistant.

b) Chronic injury is caused by long-term absorption of sulfur dioxide at sub-lethal concentrations. The symptoms appear as a yellowing or chlorosis of the leaf, and occasionally as a bronzing on the under surface of the leaves.

Susceptible Crops; Alfalfa, barley, buckwheat, clover, oats, pumpkin, radish, spinach, squash and tobacco.

Resistant crop; Asparagus, cabbage, celery, corn, onion and potato.

Effects of Fluorides on Plants

Fluorides absorbed by leaves are conducted towards the margins of broad leaves (grapes) and to the tips of monocotyledonous leaves (gladiolus). The margins or the tips of the leaves build up injurious concentrations.

The injury starts as a gray water-soaked lesion, which turns tan to reddish-brown.

With continued exposure the necrotic areas increase in size, spreading inward to the midrib on broad leaves and downward on monocotyledonous leaves.

Sensitive crops; Apricot, blueberry, peach (fruit), gladiolus

Resistant plants; Asparagus, beans, cabbage, carrot etc

Effects of Ammonia on Plants

Grasses often show reddish, inter-veinal necrotic streaking or dark upper surface discolouration.
Flowers, fruit and woody tissues usually are not affected, and in the case of severe injury to fruit trees, recovery through the production of new leaves can occur.

Sensitive species; Apple, beans, radish, raspberry and soybean.

Resistant species; Beet, carrot, corn, cucumber, eggplant, onion.

Effect of Particulate Matter (PM)

Particulate Matter is one of the greatest threat to the survival of plants. Particulate matter such as cement dust, magnesium-lime dust and carbon soot deposited on stomata of plants leaf can inhibit the normal respiration and photosynthesis mechanisms. they block the passage of air through the stomata.

Which condition, Moist or Dry PM (Particulate Matter) is the most damaging?

In moist conditions, cement dust may cause chlorosis and death of leaf tissue by the combination of a thick crust and alkaline toxicity. Thus, the moist condition is more chronic than the dry condition.
The dust coating (Figure) may also affect the normal action of chemicals applied as sprays.
Accumulation of alkaline dusts in the soil can increase soil pH to levels adverse to crop growth.

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