Assertion : Long distance flow of photoassimilates in plants occu

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 Multiple Choice QuestionsMultiple Choice Questions

171.

Assertion: Movement of materials inside phloem is bidirectional i.e. it can be both upwards or downwards.

Reason: Movement of molecules inside xylem is unidirectional i.e. always upwards.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


172.

Assertion: Light is one of the important factor in transpiration.

Reason: It induces stomatal opening and closing. Therefore, transpiration increases in light and
decreases in dark.

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


173.

Which of the following helps in ascent of sap?

  • Root pressure

  • Transpiration

  • Capillarity

  • All of these


174.

Grafting is successful in dicots but not in monocots because the dicots have

  • vascular bundles arranged in a ring

  • cambium for secondary growth

  • vessels with elements arranged end to end

  • cork cambium


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175.

In the sieve elements, which one of the following is the most likely function of P-proteins

  • Deposition of callose on sieve plates

  • Providing energy for active translocation

  • Autolytic enzymes

  • Sealing mechanism on wounding


176.

A scion is grafted to a stock. The quality of fruits produced will be determined by the genotype of

  • stock

  • scion

  • both stock and scion

  • neither stock nor scion.


177.

Assertion: When the ambient temperature is high and soil contains excess of water, the plants tend to lose water in the form of droplets from lenticels.

Reason: Root pressure regulates the rate of loss of water form lenticels

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


178.

Assertion: In angiosperms the conduction of water is more efficient because their xylem has vessels.

Reason: Conduction of water by vessel elements is an active process with energy supplied by xylem parenchyma rich in mitochondria

  • If both assertion and reason are true and reason is the correct explanation of assertion

  • If both assertion and reason are true but reason is not the correct explanation of assertion

  • If assertion is true but reason is false

  • If both assertion and reason are false.


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179.

Companion cell in plants are associated with

  • vessels

  • sieve elements

  • sperms

  • guard cells


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180.

Assertion : Long distance flow of photoassimilates in plants occurs through sieve tubes.

Reason : Mature sieve tubes have parietal cytoplasm and perforated sieve plates.

  • If both Assertion and Reason are true and the reason is the correct explanation of the assertion

  • If both Assertion and Reason are true but the reason is not the correct explanation of the assertion

  • If Assertion is true statement but Reason is false

  • If both Assertion and Reason are false statements


A.

If both Assertion and Reason are true and the reason is the correct explanation of the assertion

The main function of sieve tube is the transport of food products from green and storage organs of the plant to other organs of the plant. The sieve clements are sieve tubes arranged one above the other and have sieve plates (obligue or transverse perforated septa) on their end walls. The cytoplasm occur in the form of a thin living layer along the inner side of cellulose wall. The nucleus disappears in mature sieve elements.


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