Question

when pollen tube enters by integument then the process is called

Answer 1

In seed plants, after pollination, a pollen grain germinates, and a pollen tube grows and penetrates the ovule through a tiny pore called a micropyle. The sperm are transferred from the pollen through the pollen tube

Answer 2

When ‘pollen tube’ enters the ovule through integument it is called as Mesogamy.

Depending upon the path of entry of the ‘pollen’ into the ‘ovule’ the process is divided into distinct types that is the Progamy, Chalazogamy and the Mesogamy.

In progamy the pollen enters through the micropyle, in chalazogamy the pollen enters through the “chalazal end”.  Mesogamy is a process through which the pollens enters the ovules through its ‘middle part’ or through an integument.