Pollen Viability, Storage in Liquid Nitrogen, Pollen Allergy and Pollen Products
Biology · Sexual Reproduction in Flowering Plants · NEET
After a pollen grain is shed, it stays alive (viable) only for a limited time and must reach the stigma before it dies. In rice and wheat, pollen loses viability in just 30 minutes; in some members of Rosaceae, Leguminosae and Solanaceae it stays alive for months. Pollen can be stored for years in liquid nitrogen at -196C, forming a "pollen bank" for crop breeding. Memory hook: "Rice and Wheat rush in 30 minutes; R-L-S families relax for months; -196 is the deep freeze."
Pollen stays viable only for a short time after being shed (30 minutes in rice and wheat), but months in Rosaceae, Leguminosae and Solanaceae. For long-term use, pollen is frozen in liquid nitrogen at -196C to form a pollen bank for crop breeding.
Your doubts, answered
How long do pollen grains stay viable after they are shed?
It depends on the species, temperature and humidity. In cereals like rice and wheat, pollen loses viability within 30 minutes of release. But in some members of Rosaceae, Leguminosae and Solanaceae, pollen stays viable for months. This is a very common NEET matching point.
Why is pollen stored in liquid nitrogen and at what temperature?
Liquid nitrogen has a temperature of -196C. At this deep-freeze temperature, pollen of many species can be stored for years without losing viability. This stored pollen is used later in crop breeding programmes, so such stores are called pollen banks. NEET has directly asked the value -196C.
What is a pollen bank?
A pollen bank is a store of viable pollen kept in liquid nitrogen (-196C) so that it can be used later. It works like a seed bank. Plant breeders use it to cross plants that flower at different times or grow in different places, which helps crop breeding.
Does pollen cause allergy? Which pollen is a common allergen?
Yes. The exaggerated response of the immune system to certain antigens (allergens) in the environment is called allergy, and pollen is a common allergen causing sneezing, wheezing and breathing trouble. In many places Parthenium (carrot grass) pollen is a well-known cause of pollen allergy. This links to the immune system, so it can appear in mixed questions.
What are pollen products or pollen tablets?
Pollen grains are rich in nutrients. So pollen tablets and syrups are sold as food supplements. Their intake is claimed to increase performance in athletes and race horses. This is NCERT line content and is sometimes tested as a fact.
Is pollen viability the same as pollen germination?
No. Viability means the pollen is still alive and able to germinate. Germination is the actual growth of the pollen tube after landing on a compatible stigma. Pollen must reach the stigma while still viable, otherwise it cannot germinate and fertilisation fails.
⚠️ The NEET trap ✗ Choosing any option that contains Poaceae (rice, wheat) as a family whose pollen stays viable for months. ✓ Poaceae (rice/wheat) LOSES viability in 30 minutes. Only Rosaceae, Leguminosae and Solanaceae keep pollen viable for months. Any option with Poaceae is wrong. 🧠 The family list is the trap NTA loves.
Real NEET questions
2018
Pollen grains can be stored for several years in liquid nitrogen having a temperature of
A · -196C ✓
B · -80C
C · -120C
D · -160C
Solution: Pollen of many species can be stored for years in liquid nitrogen at -196C, forming pollen banks used in crop breeding. The other values are distractors. NCERT: it is possible to store pollen grains for years in liquid nitrogen (-196C).
2021
In some members of which of the following pairs of families, pollen grains retain their viability for months after release?
A · Poaceae ; Solanaceae
B · Rosaceae ; Leguminosae ✓
C · Poaceae ; Rosaceae
D · Poaceae ; Leguminosae
Solution: Pollen viability is variable: in rice and wheat (Poaceae) it is lost within 30 minutes, but in Rosaceae, Leguminosae and Solanaceae it lasts for months. Only Rosaceae; Leguminosae pairs two long-viability families; every option with Poaceae is eliminated.
2023
In which of the following sets of families, the pollen grains are viable for months?
A · Rosaceae, Liliaceae and Poaceae
B · Leguminosae, Solanaceae and Rosaceae ✓
C · Solanaceae, Poaceae and Liliaceae
D · Brassicaceae, Liliaceae and Poaceae
Solution: Pollen stays viable for months only in Rosaceae, Leguminosae and Solanaceae. Option 2 is the only set containing all three of these families. Sets with Poaceae, Liliaceae or Brassicaceae are wrong.
Solved Sexual Reproduction in Flowering Plants NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
At what temperature is pollen stored in liquid nitrogen?
At -196C, which is the temperature of liquid nitrogen. Pollen can be kept viable for years at this temperature.
Which families keep pollen viable for months?
Some members of Rosaceae, Leguminosae and Solanaceae keep pollen viable for months. Rice and wheat (Poaceae) lose viability in 30 minutes.
What is the use of a pollen bank?
A pollen bank stores viable pollen in liquid nitrogen for later use in crop breeding programmes, similar to how seed banks store seeds.
Which pollen commonly causes allergy in India?
Parthenium or carrot grass pollen is a common allergen. Pollen allergy can cause sneezing, wheezing and breathing problems.
What are pollen tablets used for?
Pollen is rich in nutrients, so pollen tablets and syrups are sold as food supplements. Their intake is claimed to improve performance in athletes and race horses.
