The role of pollen in plant reproduction
Pollen grains play a vital role in the reproductive process of flowering plants. The pollen grain may either be transferred through wind or through insects and birds. Their physical structure enables them to be transferred to the female parts of the plant while ensuring that the genetic information within the pollen contents is protected from the damaging effects of solar radiation.
Pollen grains
Pollen grains are the powdery substances which are released from the anthers of flowers at the onset of pollination in seed plants. The anthers are sac-like structures on the top of the flower’s stamens. They vary in grain size from the fine to the coarse and their size can range from 10 to 100 micrometres.
Preserve genetic data
Pollen grains contain the male reproductive cells which need to be transferred to the female reproductive structure of the plant. Solar radiation and dry conditions can damage the male cells. Pollen grain has a hard coating to protect and preserve the genetic data carried in the reproductive cells it contains.
The pollen grain has apertures on the wall which allow dimensional adjustments in response to changes in moisture conditions. The apertures also offer an exit route for the contents of the grain.
Pollination
Pollen grains may be conducted by wind or other organisms like insects and birds. The design and structure of pollen grains is a direct response the mode of pollination. For instance, when pollen is transferred by winds, the plants tend to produce large amounts of pollen which is lightweight so that it can be easily carried by the wind. Some species also have air sacs and winged structures to facilitate transfer. On the other hand, plants pollinated by insects produce sticky and protein-rich pollen. Such plants have conspicuous flowers to attract insects and birds. The amount of pollen produced is less as compared to wind-pollinated plants.
When pollen grains are transferred and received by the female tissue, the pollen germinates to create a pollen tube which transfers the sperm to the ovary.
