Mention two strategies evolved to prevent self-pollination in flowers.

(N/A) Self-pollination involves the transfer of pollen from the stamen to the pistil of the same flower. Two strategies that have evolved to prevent self-pollination in flowers are as follows:
$1$. Self-incompatibility: In certain plants,the stigma has the capability to prevent the germination of pollen grains from the same flower or other flowers of the same plant,thereby preventing the growth of the pollen tube. This is a genetic mechanism to prevent self-pollination.
$2$. Dichogamy: In some plants,the gynoecium and androecium mature at different times. If the gynoecium matures before the androecium,it is called protogyny. If the androecium matures before the gynoecium,it is called protandry. This temporal separation prevents the pollen from coming in contact with the receptive stigma of the same flower.