$A$ : Growth of male gametophyte is completed over the female reproductive organ.
$R$ : $2-$celled stage of partial male gametophyte is developed in-situ.
Assertion and Reason both are correct and also correct explanation.
Assertion and Reason both are correct but not explanation of assertion.
Assertion is correct, but Reason is incorrect.
Both Assertion and Reason are incorrect.
Pollens have two prominent walls which are ... $A$... and ... $B$ .... Here $A$ and $B$ refers to
The microspore tetrad of angiosperm at the time of formation, are surrounded by a callose wall. Breakdown of this wall is brought about by the enzyme callase synthesized by the
The two-celled stage of mature pollen grain consists of
An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is