Assertion: Tapetal cells usually possess dense cytoplasm and never more than one nucleus.
Reason: Tapetal cells undergo mitosis which generally involves division of nucleus but cytokinesis does not happen.
Tapetum is the innermost layer of the anther wall. They provide nourishment to developing pollen grains. Its cells called tapetal cells contain dense cytoplasm generally along with more than one nucleus. Hence, the assertion is incorrect.
This polynucleate condition arises since nuclear division is not followed by cytokinesis. Hence, the reason is correct.