Stored seed and viability
Lichens and many seeds survive long periods of dormancy by tolerating drying. The mechanisms are not currently known, but the seed-bank industry would benefit from the ability to estimate how long seeds could remain dry. The EU-funded MELISSA (Measurement of lichen and seed-survival through non-invasive assessment of metabolic activity) project developed new techniques for the purpose. Hence the team was able to assess cell viability of desiccation-tolerant plant tissues, and to match such information with changes in cell metabolites. Work also disentangled metabolic and biophysical mechanisms responsible for tolerance to desiccation. During the first year, work mostly focused on lichens. During the second year, the focus was primarily on seeds. MELISSA developed a chamber allowing control of internal environmental conditions, used for recording of thermal fingerprints during rehydration of lichens and seeds. Work also yielded techniques for artificial ageing. The techniques were developed for lichens, yet used on seeds. The team was able to non-invasively diagnose viability of plant tissues using a method involving assessment of thermal fingerprints during water uptake. The consortium further developed a method of monitoring volatile organic compounds emitted by seeds or lichens during ageing. Researchers also investigated molecular mobility in lichens, proving the absence of enzymatic reactions during the "glassy state" of severe dehydration. MELISSA helped improve the operation of seed banks, having impacts in both agriculture and conservation. The techniques supported warning of viability loss in stored seeds.
Keywords
Lichen, seed, survival, MELISSA, desiccation, metabolism
