Question

Which of the following statements is not correct?

• A. Pollen grains are released from anthers at $2$-celled stage
• B. Sporogenous cell directly behaves as the megaspore mother cell
• C. Megaspore divides twice to form an eight nucleate embryo sac
• D. Egg and synergids always lie near the micropylar end of ovule
• E. Endosperm is triploid

Answer 1

Answer: (C)

The functional megaspore is the first cell of female gametophyte. The cell enlarges and undergoes three free nuclear mitotic divisions. The first division produces two nucleate embryo sac. The two nuclei shift to the two ends and divide twice forming four nucleate and then eight nucleate structure. One nucleus from each side moves to the middle, they are called polar nuclei. The remaining three nuclei form cells at the two ends, 3 celled egg apparatus at the micropylar end and three antipodal cells at the chalazal end. The middle binudeate part organises itself into central cell. Embryo sac developed from a single megaspore is called monsporic.