|0.15| °C in defined time windows, and that RH affected the shape of these thermal fingerprints. We demonstrated that IRT can also be used to assess the viability of the lichens Lobaria pulmonaria, Pseudevernia furfuracea and Peltigera leucophlebia. No clear relationship between aerobic metabolism and the shape of thermal fingerprints was found. Conclusions Infrared thermography appears to be a promising method for the diagnosis of viability of desiccation-tolerant tissues at early stages of water uptake. For seeds, it is possible to diagnose viability within the first hours of rehydration, after which time they can still be re-dried and stored until further use. We envisage our work as a baseline study for the use of IR imaging techniques to investigate physiological heterogeneity of desiccation tolerant life forms such as lichens, which can be used for biomonitoring, and for sorting live and dead seeds, which is potentially useful for the seed trade."/>
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Table 1 Summary of treatments, materials and atmospheric conditions used for the different experiments

From: Non-invasive diagnosis of viability in seeds and lichens by infrared thermography under controlled environmental conditions

Experiment Description Type of material Atmosphere Sample specification
Exp. 1 Effects of relative humidity on the thermal fingerprints of Pisum sativum seeds Seed (P. sativum) Normoxia, 30% RH "Live": germinated (n = 20)
“Dead”: non-germinated (n = 10)
Normoxia, 100% RH "Live": germinated (n = 20)
“Dead”: non-germinated (n = 10)
Exp. 2 Effects of imbibition with water vapour and liquid water, and oxygen, on the thermal fingerprints of L. pulmonaria thallus discs Lichen (L. pulmonaria) Normoxia, 100% RH "Live": untreated (n = 15)
"Dead": microwaved (n = 15)
Anoxia, 100% RH "Live": untreated (n = 15)
"Dead": microwaved (n = 15)
Exp. 3 Thermal fingerprints of the fungal tissue in the lower cortex of L. pulmonaria discs Lichen (L. pulmonaria) “upside down” Normoxia, 100% RH "Live": untreated (n = 14)
"Dead": microwaved (n = 14)
Exp. 4 Effects of controlled deterioration on the thermal fingerprints of L. pulmonaria, P. furfuracea and P. leucophlebia thallus discs upon imbibition Lichens (L. pulmonaria, P. furfuracea and P. leucophlebia) Normoxia, 100% RH "Live": untreated (n = 14)
"Stressed": 0.3 < Fv/Fm < 0.4 after CD (n = 14)
"Dead": Fv/Fm ≤ 0.2 after CD (n = 14)
Exp. 5 Thermal fingerprints of low- and high-molecular-weight carbohydrates upon hydration Carbohydrate standards Normoxia, 100% RH Starch (n = 8)
Glucose (n = 8)
Mannitol (n = 8)
Ribitol (n = 8)
  1. Numbers of replicates are shown in brackets