AP BIOLOGY

Detailed explanation-1: -Step one: After pollen has landed on the stigma, it grows a pollen tube down through the style to the ovary. Step two: The nucleus of the pollen grain travels down the pollen tube and fertilises the nucleus in the ovule. Step three: The fertilised ovule develops into a seed.

Detailed explanation-2: -Once the pollen grain lands on the stigma at the top of the pistil, pollen tubes from the grain elongate toward the ovule. Fusion of the two gametes is required for seed formation. The male gametophyte is the pollen grain and the female gametophyte is the embryo sac 3.

Detailed explanation-3: -The pollen tube invades the pistil, growing between the walls of the stigmatic cells, then traveling through an extracellular matrix within the transmitting tissue of the style. The pollen tube finally arrives at the ovary, where it is attracted to an ovule that contains an egg cell.

Detailed explanation-4: -Fertilization is the next step after pollination. During fertilization, the male gametes from the pollen join with the female gametes in the egg. The egg, or eggs, are found inside the stigma.