Importance of Pollen Storage:
Pollen storage is crucial for plant breeding and genetic resource conservation. It enables asynchronous crossing between plants flowering at different times or from distant locations. Stored pollen also maintains genetic diversity for future research and breeding programs, especially for endangered species and those with short flowering periods.

Methods of Pollen Storage:
Pollen is stored using various methods. Short-term storage involves drying pollen with desiccants (e.g., silica gel) and maintaining cool temperatures (4-10°C), extending viability for days to weeks. Long-term storage (Cryopreservation) is highly effective. Pollen is dehydrated then stored in liquid nitrogen (-196°C). Ultra-low temperatures halt metabolic activity, preserving viability for many years.

Test Tube Fertilization:
Test tube fertilization, or in vitro fertilization (IVF), in plants, involves bringing male and female gametes together in an artificial culture medium outside the plant body. This technique overcomes in vivo fertilization barriers like pollen-stigma incompatibility or inhibited pollen tube growth in wide crosses. Pollen is germinated in vitro, and ovules (or isolated egg cells) are cultured. Pollen tubes are then guided to the ovules, facilitating fertilization under controlled lab conditions, leading to zygote formation and subsequent embryo development.