Testing seed germination from herbaria: Application of seed quality enhancement techniques and implication for plant resurrection and conservation

Herbaria are an important source of data and material useful in many fields, including plant conservation. Seeds preserved in herbarium specimens may have the potential to germinate, although few studies focused on this topic. Here, the first systematic assessment of six techniques, including priming techniques and melatonin application, aimed at improving the germination of seeds from herbarium specimens is presented. Seed germination of 26 species common in Europe, some of which congeneric to extinct species, collected in herbaria and in the wild (20,549 seeds in total, including 19,509 from 297 herbarium specimens from 8 different herbaria) was tested with the following treatments: exogenous melatonin addition to the germination medium, priming with melatonin, osmopriming, hydropriming for 24 and 48 hours, standard soil, heat sterilization and gibberellins addition. More than 85% of the fresh seeds and 1% of the seeds collected in herbaria germinated, including seeds older than 50 years. Data show that treatment with exogenous melatonin had a positive effect on the germination of fresh seeds, but a negative effect on the germination of herbarium-derived seeds. Furthermore, osmopriming treatment had a slightly positive effect on the germination of herbarium-derived seeds. Osmopriming and exogenous melatonin addition seem to be promising techniques that need further investigation and improvement and might be useful for the development of an optimal germination protocol for old and herbarium-derived seeds. The germination of seeds from herbaria could be an important tool in plant conservation, with the aim of reversing the extinction trend of many species through de-extinction, safeguarding biodiversity, and genetic variability. This study provides preliminary data for the development of germination protocols, especially for old seeds of species of conservation interest, to maximise the chance of recovering lost genetic diversity and leading to the first de-extinction ever.