Question

How tapetal cells could become bi-nucleate?

Answer 1

Stamen is the male reproductive part of a flower which is involved in production of pollen grains and consists of 2 parts: 1.Anther:Formation of pollen grains takes place in it. 2.Filament:Stalk-like structure that connects anther to the flower.

Anther consists of microsporangia in which pollen grains are produced. These microsporangia consists of four wall layers:
1.Epidermis(outermost)
2.Endodermis(below epidermis)
3.Middle layer
4.Tapetum

Tapetum is the innermost layer of anther , and it provides nourishment to developing pollen grains . Tapetal cells having a large nucleus will undergo a karyokinesis ( division of nucleus). But in tapetal cells karyokinesis is not followed by cytokinesis. Hence tapetal cells become binucleate.