HOW TAPETAL CELLS BECOME BINUCLEATE
There could be two reasons :
1)Endomitosis - Endos means inside so in this type of mitotis, the division of nucleus takes place within intact nuclear membrane(without rupturing it) which leads to polyploid nucleus.
2)Multinucleate condition - when the nuclear division is not followed by wall formation (cytokinesis) so the nucleus happens to be binucleate.