Format: ORAL

Beln Albertos1, Giuseppe Tilocca2,4, Carlos Eced1, Aleksandra Ruzic1, Ricardo Garilleti1, Francisco Lara3 Daniel Ballesteros1,4

1 Universitat de València. Spain 2 University of Natural Resources and Life Sciences. Vienna. Austria 3 Universidad Autónoma de Madrid. Spain 4 Royal Botanic Gardens, Kew. UK.

Bryophyte spores offer enormous potential for biological studies and conservation. As unicellular model for stress tolerance studies, they can provide essential information on how the land was conquered. Being key elements in reproduction and dispersal, they play important part in the biology and biogeography of the species. And for our efforts in preserving biodiversity, they can be used for efficient ex-situ conservation in spore banks. Bryophyte spores are usually unicellular, although some species produce multicellular spores because of an endosporic germination. Most bryophyte spores have fully developed chloroplasts at maturity, and our results show that they can be highly lipidic. This is a unique combination of characters in land plants propagules, as seeds and fern spores containing chlorophyll often show low storage lipids. Bryophytes have proved to be long term survivors, growing from soil banks after a century (e.g.,Bruchia vogesiaca,Physcomitrium eurystomum). However, our comparative studies suggest that they are generally short lived at room or experimentally controlled conditions. This may be related to the unique combination of spore characters mentioned above. To improve our knowledge on these structures we should learn about their physiology (e.g., type of storage lipids, contents of chlorophyll, other pigments, and antioxidants), ecology (e.g., relationship between desiccation tolerance and xerocastic/hygrochastic dispersal) and biogeographic implications (e.g., how differences concerning spore features justify differing distribution patterns in related taxa). Finally, for the purpose of ex-situ conservation, we should experimentally understand the storage conditions that preserve their maximum longevity. Moreover, we must decipher the parameters for the optimal spore germination and protonemal growth in a large and diverse number of species. We aim to offer a brief overview of current knowledge and future perspectives of this line of research because, despite their importance, our knowledge of bryophyte spores is still fragmentary and sometimes contradictory.