Tag: botany

Questions Related to botany

Which of the following helps in respiration of lichens?

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Isidia

  2. Soredia

  3. Cyphella

  4. Cephalodia

Show answer
Correct Option: C
Explanation:

Cyphella are aerating organs in the form of organised breaks, which occur in the lower cortex and appear as concave circular depression where white medulla is exposed.

Which are sensitive to sulphur dioxide pollution?

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Algae

  2. Mosses

  3. Lichens

  4. Ferns

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Correct Option: C
Explanation:

The correct answer is 'lichens'

lichens are the most sensitive indicators of sulphur dioxide pollution as their growth is inhibited due to its presence. Sulphur gets accumulated in them destroying chlorophyll and inhibiting photosynthesis.

There exists a close association between the algae and the fungus within a lichen. The fungus

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Fixes the atmospheric nitrogen for the alga.

  2. Provides protection, anchorage and absorption for the alga.

  3. Provides food for the alga.

  4. Releases oxygen for the alga.

Show answer
Correct Option: B
Explanation:

The photobiont supplies the association of organic carbon from photosynthesis, and the mycobiont ensures protection, and regulates the supply of minerals and water. The nutritional exchange between partners is probably much more complex than exchange of water and minerals for organic carbon.

A teacher was explaining about a constant physical contact involving almost equal physiological interdependence in two different thalloid forms. He was trying to explain, which one of the following?

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Mycorrhizal association

  2. Establishment of heterothallism

  3. Operation of heterothallism

  4. Advent of lichen formation

Show answer
Correct Option: D
Explanation:

The teacher was explaining the advent of lichen formation. A lichen is made up of a simple photosynthesising organism, usually green algae or cyanobacteria, surrounded by filaments of a fungus. Generally, most of lichens bulk is made of interwoven fungal filaments, although in filamentous and gelatinous lichens this is not the case. The fungus is called as a mycobiont. The photosynthesizing organism is called as a photobiont. Algal photobionts are called as phycobionts. Cyanobacteria photobionts are called as cyanobionts. The part of a lichen that is not involved in reproduction, the "body" or vegetative tissue" of a lichen, is called as the thallus. The thallus form is very different from any form, where the fungus or alga are growing separately. The thallus is made up of filaments of the fungus called as hyphae. The filaments grow by branching then rejoining to create a mesh, which is called being. The mesh of fungal filaments may be dense or loose.

Thus, the correct answer is option D.

Lichens are well known combination of an alga and a fungus where fungus has

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. A parasitic relationship with the alga.

  2. A symbiotic relationship with the alga.

  3. A saprophytic relationship with the alga.

  4. An epiphytic relationship with the alga.

Show answer
Correct Option: B
Explanation:

Lichen is a stable symbiotic association between a fungus and algae. The combined life form has properties that are very different from the properties of its component organisms. Lichens come in many colors, sizes, and forms. The properties are sometimes plant-like, but lichens are not plants. 

Lichens grow at a very slow rate (1 mm per year). In how many years, a lichen matures?

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. 1 - 4 years

  2. 4 - 8 years

  3. 100 years

  4. 20 - 25 years

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Correct Option: B
Explanation:

Lichens usually reach maturity and produce ascocarps at 4-8 years of age. The age of some lichens in alpine-arctic area is 1000-4500 years. Their longevity can be partially attributed to their ability to survive long periods of drought unharmed.

Thus, the correct answer is option B.

In majority of lichens, there is association of

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Green algae and ascomycetes

  2. Green algae and basidiomycetes

  3. Blue green algae and ascomycetes

  4. Blue green algae and basidiomycetes

Show answer
Correct Option: C
Explanation:

The lichen fungi (kingdom Fungi-ascomycetes) cultivate partners that manufacture food by photosynthesis. Sometimes, the partners are algae (kingdom Protista), other times cyanobacteria (kingdom Monera), formerly called as blue-green algae.

Thus, the correct answer is option C.

Which of the following can photosynthesis at low temperature (-20$^{0}$C) ______________.

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Bacteria

  2. Lichen

  3. Yeast

  4. Batrachospermum

Show answer
Correct Option: B
Explanation:

Lichen's can photosynthesis at a very low temperature.
i.e.,−20C−240C

So the correct option is B.

A harmful lichen is

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Lobaria

  2. Cladonia

  3. Usnea

  4. Rocel!a

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Correct Option: C
Explanation:

In hot season, Usnea get dry and become highly inflammable. It easily catches fire and causes forest fire.

Which of the following structure helps in the respiration of lichens _____________.

botany adaptations to different ecosystems lichen lichens lichens ( the nature's pioneers )

  1. Soredia

  2. Cyphella

  3. Isoidia

  4. Cephalodia

Show answer
Correct Option: B
Explanation:
The cyphellae are small circular depressions and are found irregularly scattered on the underside of some lichens such as Sticta. They have a definite rim made of spherical thin walled cells and open into the medulla of the lichen. 
So, the correct answer is 'Cyphella'