The entry of the pollen tube into the ovule through the micropyle is called:

In wheat and rice,pollen grains lose viability within $30$ minutes of their release. In members of the families Rosaceae,Leguminosae,and Solanaceae,the viability is maintained for $...$.

Where does the pollen tube develop?

When the pollen tube enters the ovule through the funiculus or the integuments,it is called:

What acts as a mediator in the pollen-pistil interaction?

$A$: Certain proteins of pollen origin identify the compatible stigma.
$R$: Compatibility proteins are located in the ektexine.