Discuss the various types of pollen tube entry into ovary with the help of diagrams.

Explanation

Pollen tube enters into the ovule by any one of the three ways.
1) Porogamy : Pollen tube enters into ovule through Micropyle and then enters into embryosac by destroying one of the synergids.
E.g. : Ottelia, Hibiscus.
2) Chalazagamy : Pollen tube enters into ovule through chalaza.
E.g. : Casuarina.
3) Mesogamy : Pollen tube enters into ovule through the integuments.
E.g. : Cucurbita,