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

Explanation

(1) Dicliny : It is the condition where one of the two sexes is absent in the flower and the flower becomes a unisexual male or female (diclinous). Such diclinous flowers may be borne either on the same plant or on the two different plants. In such cases, cross pollination is the rule, e.g. maize, cucurbita.
(2) Herkogamy :(Herkos - barrier) It is the condition where the style of the gynoecium extending far beyond the anthers or stamens may face outward or pollens may aggregate into pollinia. In such cases, self pollination is impossible. e.g gloriosa, calotropis.