Male gametes in double fertilisation enter the embryo sac through synergid cells even in chalazogamy i.e. when polen tube enters the ovule through chalazal end. Regarding the fact that compatibility reaction has already taken place (i.e. they are the right gametes) after pollination then why male gametes doesn't enter through antipodal cells? Is it just because of filiform apparatus that affiliates the entry of male gametes through only synergid cells or is there something else as a reason?