Question

Match the pair and explain growth of pollen tube towards ovule brainly

Answer 1

Pollen tube enters in the ovary at that time, ovules become mature. Inside the ovary obturators guide the passage of pollen tube towards the micropyle. A mature ovule in which embryo sac has also matured, has three paths for the entry of pollen tube -

I) POROGAMY - In this, pollen tube enters into the ovule through micropyle. It is found in most of the angiosperms.

II) CHALAZOGAMY - In this, pollen tube enters into the ovule through the chalaza.
Eg- Cassuarina, Betula, Walnut

III) MESOGAMY - In this, pollen tube enters into the ovule either through the integuments (Cucurbita) or through funiculus (Pistacia and Populus).

After the entrance inside the ovule, it grows towards the egg apparatus because synergid cells secrete the chemicals with the help of filiform apparatus which attract the pollen tube and guide the pollen tube. It means pollen tube shows chemotropic movement in ovary.