Q.(a) Explain the modern methods of seed storage. OR

(a) Modern seed storage relies on dried low-moisture gene banks and liquid-nitrogen cryopreservation; (b) five common medicinal plants and the plant part/use each contributes.

(a) Modern methods of seed storage

Conserving crop germplasm (genetic diversity) for future breeding use relies on modern, controlled seed-storage methods:

1. Seed (gene) banks: orthodox seeds (those that tolerate drying and low temperature) are first dried down to a low moisture content (about 5-7%) to slow their metabolism, then stored in sealed containers under refrigerated (low, often sub-zero, e.g. around -18 degC) and low-humidity conditions, which can preserve seed viability for years to decades. National and international gene banks (e.g. India's National Bureau of Plant Genetic Resources, NBPGR, New Delhi, and the global Svalbard Global Seed Vault) maintain such long-term collections.
2. Cryopreservation: for ultra-long-term (potentially indefinite) conservation, or for germplasm that cannot be stored as dry seed (recalcitrant seeds, pollen, shoot tips/meristems, embryos), material is stored at extremely low temperature in liquid nitrogen at about -196 degC, which halts virtually all metabolic and biochemical deterioration.
3. In vitro (tissue-culture) gene banks: germplasm can also be conserved as slow-growth tissue cultures maintained under controlled, growth-retarding conditions, useful for vegetatively propagated species and for material difficult to store as seed.

(b) Medicinal uses of the named plants