If the petals of a flower are reduced how is the plant pollinated

The plant is most likely to rely on wind and water for pollination

Explanation:

because of no nectar or reduction of nectar the plan would most like switch to pollination by wind or water

If this fails then the plant may not likely  reproduce

1. Over-hunting
2. A disappearance of a primary food source
3. Drought
4. A more competitive species taking food
5. Different environment conditions that is difficult for the species to survive
6. Something killing off a certain gender of a species
Hope it helps! :)