Question

Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.

Answer 1

The outbreeding devices in flowering plants which encourage crosspollination are

(i) Dicliny: Flowers are unisexual so that self-pollination is not possible. The plants may be monoecious bearing both male and female flowers (e.g. maize) or dioecious bearing male and female flowers on individual plants (e.g. mulberry, papaya).

(ii) Prepotency: Pollen grains of another flower germinate more rapidly over the stigma than the pollen grains of the same flower. Examples: Apple, grape

(iii) Self-sterility: Pollen grains of a flower do not germinate on the stigma of the same flower because of the presence of similar self-sterile genes. Examples: Tobacco, potato, crucifers