Question

Difference between gametangial contact and gametangial copulation

Answer 1

Gametangial contact and gametangial copulation are  both different forms of sexual reproduction amongst organisms.

In gametangial contact, only the male nuclei enter the female gametangium, through the development of a pore and a tube while in gametangial copulation, the entire protoplasm of the male gametangium enters the female gametangium. 
Gametangial contact can be seen in oomycetes and ascomycetes while gametangial copulation occurs in organisms like trichomycetes and zygomycetes.

Answer 2

In gametangial contact, male and female gametangia never fuse with each other. As a result, they do not lose their identities during the sexual act.

In gametangial copulation, male and female gametangia come in close contact with each other and get fused. Because of this, the contents of both the types get mixed with each other.