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Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 ScienceBIOLOGYSexual Reproduction in Flowering Plants1 Mark
Question
For two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
  1. Both assertion and reason are true, and reason is the correct explanation of assertion.
  2. Both assertion and reason are true, but reason is not the correct explanation of assertion.
  3. Assertion is true, but reason is false.
  4. Both assertion and reason are false.
Assertion: Mostly in a tetrad, all microspores are free.
Reason: Compound pollen grain and pollinium are formed by grouping of microspores.
✓

Answer

  1. Both assertion and reason are true, but reason is not the correct explanation of assertion.

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Explanation:

Mostly, all the four spores within a tetrad are completely isolated from one another and from the spores in other tetrads of the locale. Usually the microspores separate from one another shortly after meiosis. However, in some plants the spores tend to remain together in tetrads for longer period and develop into compound pollen grains. In many members of Orchidaceae and Asclepiadaceae all the microspores in a sporangium remains together to form what is called a pollinium.

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