Characterizing non-lethal damage within dry seeds may allow us to detect early signs of ageing and accurately predict longevity. We compared RNA degradation and viability loss in seeds exposed to stressful conditions to quantify relationships between degradation rates and stress intensity or duration. We subjected recently harvested (‘fresh’) ‘Williams 82’ soya bean seeds to moisture, temperature and oxidative stresses, and measured time to 50% viability (P50) and rate of RNA degradation, the former using standard germination assays and the latter using RNA Integrity Number (RIN). RIN values from fresh seeds were also compared with those from accessions of the same cultivar harvested in the 1980s and 1990s and stored in the refrigerator (5°C), freezer (−18°C) or in vapour above liquid nitrogen (−176°C). Rates of viability loss (P50−1) and RNA degradation (RIN⋅d−1) were highly correlated in soya bean seeds that were exposed to a broad range of temperatures [holding relative humidity (RH) constant at about 30%]. However, the correlation weakened when fresh seeds were maintained at high RH (holding temperature constant at 35°C) or exposed to oxidizing agents. Both P50−1 and RIN⋅d−1 parameters exhibited breaks in Arrhenius behaviour near 50°C, suggesting that constrained molecular mobility regulates degradation kinetics of dry systems. We conclude that the kinetics of ageing reactions at RH near 30% can be simulated by temperatures up to 50°C and that RNA degradation can indicate ageing prior to and independent of seed death.

中文翻译：

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与正统种子衰老和死亡相关的压力-反应关系：一项比较大豆 (Glycine max) cv 中的活力和 RNA 完整性的研究。威廉姆斯 82

表征干燥种子中的非致命损伤可能使我们能够检测到衰老的早期迹象并准确预测寿命。我们比较了暴露于压力条件下的种子的 RNA 降解和活力损失，以量化降解率和压力强度或持续时间之间的关系。我们对最近收获的（“新鲜”）“Williams 82”大豆种子进行水分、温度和氧化应激，并测量达到 50% 活力 (P50) 的时间和 RNA 降解率，前者使用标准发芽试验，后者使用RNA 完整性编号 (RIN)。还将新鲜种子的 RIN 值与 1980 年代和 1990 年代收获并储存在冰箱（5°C）、冷冻室（-18°C）或液氮上方的蒸汽（-176°）中的同一品种的 RIN 值进行比较C）。活力丧失率 (P50-1) 和 RNA 降解 (RIN⋅d-1) 在暴露于广泛温度范围的大豆种子中高度相关[保持相对湿度 (RH) 恒定在约 30%]。然而，当新鲜种子保持在高相对湿度（保持温度恒定在 35°C）或暴露于氧化剂时，相关性减弱。两者都是 P50-1和 RIN·d-1参数在 50°C 附近表现出 Arrhenius 行为的中断，表明受限的分子迁移率调节了干燥系统的降解动力学。我们得出结论，可以通过高达 50°C 的温度来模拟 RH 接近 30% 时的老化反应动力学，并且 RNA 降解可以表明在种子死亡之前和独立于种子死亡的老化。