Pollen Viability and Storage

Pollen grains are exceptionally rich in nutrients. Their composition includes:

Pollen as a Food Supplement:

• In recent years, it has become fashionable to use pollen tablets and syrups as food supplements.
• In Western countries, a large number of pollen products (tablets, syrups, creams, energy shakes) are available commercially.
• Pollen consumption has been claimed to increase the performance of athletes and race horses.

Viability is the ability of pollen grains to germinate and bring about fertilisation after being shed from the anther.

Once shed, pollen grains must land on the stigma before they lose viability. If they lose viability before reaching the stigma, fertilisation cannot occur.

Factors Affecting Viability:

The period for which pollen grains remain viable depends on:

1. Prevailing Temperature - Higher temperatures generally reduce viability faster.
2. Humidity - Excess moisture or extreme dryness shortens the viability period.

Viability Duration:

Need for Long-Term Storage:

Some species lose pollen viability within minutes. For crop breeding programmes, artificial hybridisation, and biodiversity research, there is a critical need to store pollen for extended periods.

Method- Cryopreservation:

Cryopreservation is the technique of storing biological material at ultra-low temperatures to preserve its viability indefinitely.

• Pollen grains of a large number of species can be stored for years in liquid nitrogen at −196°C.
• At this temperature, all metabolic activity ceases, and the pollen remains viable until needed.

A Pollen Bank is a facility where pollen grains of various plant species are stored under cryopreservation conditions (liquid nitrogen, −196°C) for future use — similar to Seed Banks that store plant seeds for preservation.

Uses and Importance of Pollen Banks:

1. Viability = ability of pollen to germinate and cause fertilisation after being shed.
2. Pollen must reach the stigma before losing viability, otherwise fertilisation fails.
3. Viability depends on temperature and humidity — varies greatly by species.
4. Rice & Wheat pollen loses viability within 30 minutes of release.
5. Rosaceae, Leguminosae, Solanaceae pollen stays viable for several months.
6. Pollen can be stored for years in liquid nitrogen at −196°C (cryopreservation).
7. Stored pollen is kept in Pollen Banks — similar to seed banks.
8. Pollen banks are used in crop breeding programmes and biodiversity conservation.