Question

Which of the following is the most suitable indicator of sulphur dioxide pollution in the environment
A. Fungi
B. Lichens
C. Conifers
D. Algae

Answer 1

Hint: Sulphur dioxide emissions mainly occur through power plants, refineries, industries, smelters, trains etc. The largest source is fossil fuel combustion. It causes air pollution leading to respiratory illness. Its emissions also contribute to smog and acid rain.

Complete answer: Lichens are a symbiotic association of algae and fungi. Lichens derive their nutrition from the air and are not able to grow in the area having high levels of sulphur dioxide. Because of industrialization, many species of lichens have died and some have gone extinct already. Lichens arise from Cyanobacteria living symbiotically with fungal filaments. Both have a mutualistic association. Different types of lichens are Fruticose that have leafless branches, foliose that has a leaf-like structure and crust-like appearances called Crustose and powder-like called Leprose.
a) Fungi: Eukaryotic organisms include yeasts and moulds. These organisms have a filamentous body except yeast. The cell wall is made up of chitin. Fungi are mainly saprophytic, parasitic or symbiotic.
b) Conifers are gymnosperms. They have vascular tissues. Order Pinales constitute conifers. Conifers are cone-bearing vascular plants and include cedar, junipers, pines, redwood, etc.
c) Algae are photosynthetic eukaryotic organisms. They lack true roots, stems and leaves. They are photosynthetic organisms and range from microscopic diatoms to multicellular kelps.
Hence, the correct answer is option B.

Note: Both algae and fungi are mutually beneficial to each other. Lichens also indicate sulphur dioxide pollution through morphological, anatomical and physiological changes. They also show a sharp decline in growth in high levels of sulphur dioxide.