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Grasses fling clouds of light pollen to the wind; bright flowers bribe bees with nectar. Each plant has a strategy to get its pollen delivered.
- Pollination depends on external agents called pollinators — wind, water, insects or birds.
- Wind : light pollen and feathery stigmas (wheat, maize, rice); water : currents carry pollen (Vallisneria, Hydrilla).
- Insects : bright, scented, nectar-rich flowers with sticky pollen (sunflower, hibiscus, marigold); birds : some flowers are pollinated by sunbirds and the Indian white-eye.
In this Activity, we will find out how two pollination strategies compare by analysing pollen and seed data in Table 11.3.
- Study the data on pollen production and seed formation for two pollination strategies (Table 11.3).
- Compare the two strategies for their pollen-to-seed ratio.
- Compare their efficiency of pollination and seed formation.
- Explain why producing a very large number of pollen grains can still be an effective strategy.
| Pollination strategy | Approximate pollen grains released per flower | Estimated average number of seeds formed |
|---|---|---|
| Wind-pollinated grasses (e.g., maize, wheat) | 5,00,000–10,00,000 | 50–200 |
| Insect-pollinated plants (e.g., sunflower) | 20,000–40,000 | 800–1,000 |
P. Maheshwari , known as the ‘Father of Indian Embryology’, was a leading scientist in the study of plant reproductive organs. He developed the technique of in-vitro fertilisation in flowering plants by fusing an egg and male gamete in a test tube to create new hybrid plants, and grew plant embryos on artificial nutrient media. His book, An Introduction to the Embryology of Angiosperms (1950), is still widely used.
