Seeds are increasingly being stored in seed banks for ex situ conservation, food security, and restoration reserves. Although it is hypothesized that seeds of many species can survive the dry, freezer conditions (−20°C) of seed banks for many years, shelf life is unknown for many species. In particular, changes to dormancy and germination requirements following freezer storage have not yet been studied extensively. To improve our understanding of how seed dormancy and germination respond to seed banking conditions, we evaluated seed of six restoration-priority species in the southwestern United States, which is a region of increasing restoration need. Germination tendencies of seeds that were and were not exposed to a −20°C treatment for 4–6 months were evaluated under 22 cold-moist stratification and incubation treatments to broadly assess changes to dormancy and germination requirements and speed. Direct or indirect (via interactions with stratification and/or incubation treatments) differences in dormancy breaking and germination were observed in seeds for four of the six species studied. Specifically, storage temperature accounted for differences in the final germination proportion, germination during stratification, and/or rate of germination in five of the six species. Notably, seeds of the one species that exhibit a combination of physiological and physical dormancy showed significant differences in all germination measures. However, while significant differences were found between seeds exposed to short-term seed bank storage and those that were not, these differences were small and may not be biologically meaningful, indicating that seed banking these species should not change how they are used for restoration or reintroduction purposes.

中文翻译：

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暴露于短期种子库条件 (-20°C) 后原产于美国西南部的杂草的发芽行为

种子越来越多地储存在种子库中异地保护、粮食安全和恢复储备。尽管假设许多物种的种子可以在种子库的干燥冷冻条件（-20°C）下存活多年，但许多物种的保质期是未知的。特别是，冷冻储存后休眠和发芽要求的变化尚未得到广泛研究。为了提高我们对种子休眠和发芽如何响应种子库条件的理解，我们评估了美国西南部六种恢复优先物种的种子，这是一个恢复需求不断增加的地区。在 22 种冷湿分层和孵化处理下评估了暴露于 -20°C 处理 4-6 个月和未暴露于 -20°C 处理的种子的发芽趋势，以广泛评估休眠和发芽要求和速度的变化。在所研究的六个物种中的四个的种子中观察到直接或间接（通过与分层和/或孵化处理的相互作用）休眠破坏和发芽的差异。具体而言，储存温度解释了最终发芽比例、分层期间发芽和/或六个物种中五个物种的发芽率的差异。值得注意的是，表现出生理和物理休眠相结合的一个物种的种子在所有发芽测量中都表现出显着差异。然而，虽然暴露于短期种子库储存的种子与未暴露的种子之间存在显着差异，但这些差异很小，可能没有生物学意义，