Gametes that fertilize an ovum are called the sperms
Explanation
The reproductive cells of an organism are called the gametes or sex cells. Female sex cells are the ova/egg where as male sex cells are the sperms. The sperms are stored in the scrotum after their production in the male testes where as the eggs for females mature in female ovaries. During fertilization, sex cells meet in the Fallopian tube.
If the plants are growing under the ice and the ice is floating above it on the surface of the water and the ice blocks the light from getting to the plant.