Experimental Seed Germination for Ex Situ Conservation of Mexican Podostemaceae

Background: Podostemaceae are extremely susceptible to local extinction by habitat loss. Since ~70 % of the river systems in Mexico show some degree of water contamination, it is relevant to generate information about seed storage and germination behavior to design germplasm conservation strategies ( e.g ., ex situ seed banks) of Mexican podostemads. Hypotheses: Seed germination decreases as seed storage time increases. Further, light quality, temperature and collection site influence similarly the germination response of both species. Studied species: Marathrum foeniculaceum Humb. & Bonpl., Noveloa coulteriana (Tul.) C. Philbrick Study site and years of study: 13 different seeds collections (1996-2013), at four locations in the rivers Horcones and Arroyo del Rincon Jalisco, México. Methods: A germination chamber experiment was performed to evaluate the effect of temperature, light quality and storage time on the germination of both species. Results: Seeds lose viability after nine years of storage. In both species, the time to reach the highest Accumulated Germination Percentage (AGP) was faster in seeds of one-two yr compared to seeds of six-seven yr. N. coulteriana have significant differences in Final Germination Percentage (FGP) between collection rivers. Storage time affects AGP of N. coulteriana more than in M. foeniculaceum. Conclusions: Both species can form ex situ seed banks up to 8 yr age in paper bags storage. N. coulteriana is more susceptible to variation in storage conditions compared to M. foeniculaceum . Collection site affect seed germination after storing. Long-term conventional ex situ seed germination storage is not a viable strategy to conserve germplasm of Podostemaceae.