In the conservation of endangered plant species, seed banks are a key ex-situ method to maintain biodiversity. To ensure long-term preservation, the storage environment must be carefully controlled and the viability of the collection must be regularly monitored.
Which of the following describes the correct scientific basis for the standard storage conditions of orthodox seeds and the method used to monitor their viability over time?
Seeds are dried to approximately 5–8%5\text{--}8\%5–8% moisture content and frozen at −20∘C-20^\circ\text{C}−20∘C to minimise metabolic rate and prevent fungal decay; viability is monitored by periodic germination tests on representative samples.
Seeds are stored in a highly humid, oxygen-rich environment at 4∘C4^\circ\text{C}4∘C to support continuous slow growth of the embryo; viability is monitored by measuring the heat released from cellular respiration.
Seeds are instantly freeze-dried and stored in liquid nitrogen at −196∘C-196^\circ\text{C}−196∘C to preserve cellular structure; viability is monitored using chlorophyll fluorescence of the seed coat.
Seeds are completely dehydrated to 0%0\%0% moisture content and kept in an airtight vacuum to eliminate all respiration; viability is monitored by measuring mass loss of the entire storage batch over time.