A pollen grain consists of two cells: the generative cell and the tube cell. Differentiate between the cells?

could you help me answer this question? i also have to know when is the pollen tube formed and what is its function?



Could you help me with the answer or give me a site that has it? thanks

A pollen grain consists of two cells: the generative cell and the tube cell. Differentiate between the cells?
Each pollen grain contains vegetative cells (only one in most flowering plants but several in other seed plants) and a generative cell containing a tube nucleus (that produces the pollen tube) and a generative nucleus (that divides to form the two sperm cells).The group of cells is surrounded by a cellulose cell wall and a thick, tough outer wall made of sporopollenin.



The pollen tube acts as a conduit to transport sperm cells from the pollen grain, which has landed on the stigma, to the ovules at the base of the pistil. The pollen tube germinates from the pollen grain and grows the entire length through the stigma, style and ovules to reach the eggs.

The sperm cells by themselves are not motile and are carried within the tube. As the tip of the tube reaches an egg it bursts and releases two sperm cells leading to a double fertilization. One sperm unites with the ovum (egg) to produce the embryo of a new plant while the second sperm unites with the central cell to produce the endosperm of the seed.
Reply:Inside the pollen wall are two cells. The cell with lots of bluish cytoplasm (filling up the inside of the pollen wall) is the tube cell. The smaller cell (on top of the tube cell) is the generative cell. Notice that both cells have a lavender nucleus and each nucleus has a red nucleolus. The nuclei of the two cells are the same size...the cells differ in the amount of cytoplasm present. The tube cell has much cytoplasm, the generative cell has far less.



The tube cell grows to penetrate the pollen wall and then the stigma and style tissues of the carpel. This penetrating cell is now called the pollen tube. Its growth is chemotropic (grows toward a source of chemicals)...likely toward calcium, boron, and/or auxin. The chemical source is an ovule. The pollen tube's chemotropism results in the tube arriving in a small opening in the ovule's integument...the micropyle.

The pollen tube arrives in the micropyle of the integument of the ovule, and enters the embryo sac.



The synergids of the embryo sac literally put their energies together to burst the end of the pollen tube. Meanwhile, the generative cell has followed the pathway digested by the tube cell. Along the way it has divided to produce two sperm cells. The two sperm cells exit the pollen tube through the burst end.



The pollen tube acts as a conduit to transport sperm cells from the pollen grain, which has landed on the stigma, to the ovules at the base of the pistil. The pollen tube germinates from the pollen grain and grows the entire length through the stigma, style and ovules to reach the eggs.
Reply:ok one is the bit that grows into the tube that the gamete will travel down to meet the ouvle and one is the gamete the generative cell