A Pollen Tube Together with Its Contents of Male Gametes

Question

A pollen tube together with its contents of male gametes constitutes the ____.  
A) male reproductive organ
B) endosperm mother cell
C) mature male sporophyte
D) immature male gametophyte
E) mature male gametophyte

Accepted Answer

A pollen tube is a structure formed by the male gametophyte to transport the male gametes to the female gametophyte. Therefore, the pollen tube together with its contents of male gametes constitutes the mature male gametophyte. Choice A is incorrect because a pollen tube is not a male reproductive organ, but rather a structure formed by it. Choice B is incorrect because the endosperm mother cell is a structure inside the female reproductive organ and has no relation to the pollen tube. Choice C is incorrect because the mature sporophyte is the result of fertilization, which involves the fusion of male and female gametes. The pollen tube and its contents are exclusively male. Choice D is incorrect because the immature male gametophyte is the structure that produces the pollen tube and is located inside the anther of a flower. The pollen tube and its contents have already matured and left the anther when they are transported to the female reproductive organ.