Assertion: Nuclear endosperm is formed by subsequent nuclear divi

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 Multiple Choice QuestionsMultiple Choice Questions

131.

Upon fertilization, what structure develops from carpel?

  • Testa

  • Tegmen

  • Pericarp

  • Perisperm


132.

Assertion: In some species of asteraceae and poaceae seeds are formed without fertilization.

Reason: Formation of fruit without fertilization is called parthenocarpy.

  • 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.


133.

Even after killing the generative cell with a laser beam, the pollen grain of a flowering plant germinates and produces normal pollen tube because

  • laser beam stimulates pollen germination and pollen tube growth

  • the laser beam does not damage the region from which pollen tube emerges

  • the contents of killed generative cell permits germination and pollen tube growth

  • the vegetative cell has not been damaged


134.

Assertion : Protandry and protogyny ensures cross fertilization.

Reason : Cross fertilization introduces variation in progeny.

  • 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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135.

Assertion : Pollen mother cells (PMCs) are the first male gametophytic cells.

Reason : Each PMC gives rise to two pollens.

  • 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


136.

Which one of the following pairs of plant structures has haploid number of chromosomes

  • Nucellus and antipodal cells

  • Egg nucleus and secondary nucleus

  • Megaspore mother cell and antipodal cells

  • Egg cell and antipodal cells


137.

Assertion : Emasculation prevents self- pollination in flowers.

Reason : Emasculation is the removal of anthers from a bisexual flower.

  • 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.


138.

Assertion: Maize is an albuminous seed. 

Reason: Endosperm is completely absorbed by its growing embryo

  • 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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139.

Apomixis is

  • formation of seeds by fusion of gametes

  • formation of seeds without syngamy and meiosis

  • formation of seeds with syngamy but no meiosis

  • none of the above


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140.

Assertion: Nuclear endosperm is formed by subsequent nuclear division without wall formation.

Reason: Coconut is an example of such endosperm, where the endosperm remains nuclear throughout the development of the fruit

  • 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.


C.

If assertion is true but reason is false

In nuclear endosperm, first and further divisions of primary endosperm nucleus arc not followed by cytokinesis or wall formation and thus these free nuclear divisions lead to formation of a large number of free nuclei in embryo sac. At maturity, centripetal wall formation may occur to make the tissue partly cellular. Endosperm of coconut is unique in sense that it is both nuclear and cellular. Here the primary endosperm nucleus undergoes a number of free nuclear divisions. When the fruit is about 50 mm long the embryo sac remains filled with a watery fluid or milk containing free nuclei and fine cytoplasmic particles. At a later stage when the fruit becomes about 100mm in length the liquid shows in addition to free nuclei, several cells each enclosing variable number of nuclei. Thus coconut has multicellular endosperm (called coconut meat) in the outer part and free


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