Question

when maturation time of reproductive parts in a flower is different

Answer 1

when maturation time of reproductive parts in a flower is different, it is called Dichogamy

Answer 2

It is called dichogamy. In bisexual flowers of the plants, when stamen and carpel do not mature at the same time it is called dichogamy.
It is of two types :
1) protandry: when anther mature earlier than carpels. Eg: salvia, cotton.
2) protogyny: when carpels mature earlier than stamen. Eg: ficus species.