Question

State any two contrivances (structural adaptations)in flowers which favour cross pollination .
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Answer 1

Answer:

When the pollen of a flower pollinates the stigma of another flower located on a different plant, whether of the same kind or not, it is called cross-pollination or allogamy.

Structural contrivances which favor cross-pollination are listed below:

1. Dicliny:

Cross-pollination is the rule among diclinous plants, i.e., those bearing unisexual flowers.

2. Self-sterility:

This is the condition when a flower cannot be fertilized by the pollen of the same flower or, sometimes, from a flower of the same strain of plants.

3. Dichogamy:

When stamens and carpels of a bisexual flower mature at different times, pollination between them becomes ineffective.

4. Herkogamy (herkos = barrier):

In some flowers there may be some physical barrier between the anther and the style so that pollination between them is rendered difficult or even impossible.