What type of growth is observed in the pollen tube?

After penetrating the stigmatic and stylar tissues,the pollen tube usually grows down towards the egg because:

What does the filiform apparatus do at the entrance into the ovule?

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

$A$: Initial growth of the pollen tube takes place at the expense of food present in the stigma and style.
$R$: The pollen tube travels intracellularly and chemotactically.

$A$ long pollen tube is found in $.......$.