Question

As a pollen tube grows into the female organ, the nucleus that enters the synergid first is called the:
A) Sperm nucleus
B) Generative nucleus
C) Tube nucleus
D) Pollen nucleus

Answer 1

Hint: The tube nucleus is the first nucleus to enter a synergid. One of the two nuclei created by the mitotic division of a microspore during the creation of a pollen grain is known as the tube nucleus, and it is retained to regulate the expansion of the pollen and not divide once more.


Step by step solution:
The vegetative cell is another name for the tube nucleus. It doesn't participate in plant fertilisation and starts to deteriorate as soon as the pollen tube begins to germinate on the stigma.
The DNA in the sperm nucleus has a distinctive chromatin structure that is severely compressed and linked to certain proteins called protamines. It is a transcriptionally dormant cell that is not dividing.
The pollen grain's generative cell nucleus divides before the tube reaches the ovule, producing two sperm nuclei that are then released into the ovule for fertilisation.
One of the two male nuclei of seed plants that go through fertilisation is the generative nucleus. The nucleus of the pollen tube directs the development of the pollen tube inside the pistil. The main distinction between the generative nucleus and the pollen tube nucleus is thus this.
Hence, option C is the correct answer.

Note:
A pollen grain has a generative nucleus and a tube nucleus as its two nuclei. In the pollen tube, the generative nucleus splits into two male gametes. Eventually, the tube nucleus breaks down.