Effects of long-term seed storage on germination of 13 cactus species from central Argentina

Understanding the effects of long-term seed storage on germination is important to elucidate both soil seed bank dynamics and capacity of seeds to be preserved in ex situ conservation programs. We collected seeds 13 cactus species from central Argentina and conducted the following experiments: germination of freshly collected seeds (2011) and germination of seeds stored for 3 (2014) and 7 years (2018) at ambient temperature. Seeds were germinated in a chamber at 25 °C and a 12 h light/12 h darkness photoperiod. After 3 years, germination decreased in 10 of the species, and only one species did not germinate. After 7 years, germination was null in 10 species, very low in two species and relatively high in only one. Our results suggest that most species might form a short-term persistent seed bank, but not a permanent soil seed bank. From a conservation point of view, our results suggest that seeds of cactus species from central Argentina would need other storage conditions, such as low temperatures. We propose a mechanism to explain why cactus seeds do not have a high longevity.