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.

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.

Which of the following helps in ascent of sap?

• Root pressure

• Transpiration

• Capillarity

• All of these

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

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

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.

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.

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.

Companion cell in plants are associated with

• vessels

• sieve elements

• sperms

• guard cells

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