In which type of flowers, the pollen grains are ribbon like without exine?

Which flower exhibits turn pipe mechanism of pollination?

The phenomenon of pollen grains of other flowers germinate rapidly on stigma than the pollen grains of same flower is …………

Inhibition of germination of pollen on stigma of same flower is ………

The stigma provides ……………… for germination of pollen on it.

For successful artificial hybridization, these processes are essential.

Continued self-pollination results in ………

Heterostyly : Primula flowers : : Herkogamy: ?

The substance having key role in recognition and compatibility of pollen in pollen – pistil interaction is …………

This is NOT a type but variation in endosperm.