Question

What is pollen pistil interaction?

Answer 1

POLLEN PISTIL INTERACTION

1. After pollination, the pollen grain gets deposited on the stigma.
2. It is two-celled having a larger tube cell and smaller generative cell.
3. The sugary secretions produced on the stigma stimulate the germination of the pollen grain.
4. The inner covering intine produces a pollen tube which comes out through a germ pore.
5. The tube nucleus enters the pollen tube first, followed by generative nucleus.
6. Soon, the tube cell disintegrates, while the generative nucleus divides by mitosis to produce two haploid male gametes.
7. The pollen tube with its contents, i.e. tube nucleus, cytoplasm and two male gametes is called male gametophyte.
8. The pollen tube bores its way through the stigma and passes down though the style towards the ovary.
9. After reaching the ovary, the pollen tube enters the ovule through the micropyle (Porogamy) and then enters one of the synergids through the filiform apparatus.
10. The extensive infoldings of the wall in the synergids at the micropylar end is called the  filiform apparatus. It plays an important role in attracting the pollen tube.
11. All the sequence of events from the deposition of pollen on the stigma till the entry of pollen tube in the ovule together is referred to as ‘Pollen Pistil interaction’.

Image Source: 

1. http://jxb.oxfordjournals.org/content/early/2010/02/24/jxb.erq021/F1.expansion.html

Answer 2

The ability of the pistil to recognise the pollen followed by its acceptance or rejection is the result of a continuous dialogue between pollen grain and the pistil